{
  "spore": "profile",
  "id": "as4-3501-6",
  "spore_version": "0.2",
  "family": "carbon-epoxy",
  "name": "Hexcel AS4/3501-6 carbon-epoxy",
  "abbreviation": "AS4/3501-6",
  "role": "structural composite laminate (graphite/epoxy facesheets in a sandwich)",
  "category": "composites",
  "type": "carbon-fiber-reinforced",
  "summary": "Hexcel AS4/3501-6 is a graphite/epoxy composite. It uses AS4 PAN-based carbon fibre woven as 8-harness satin fabric of 3K tows, in a 3501-6 epoxy resin. NASA Marshall tested it as the facesheet material of the Space Shuttle solid rocket booster composite nose cap. In the NASA lamina tests at 75 °F, the warp tensile strength averaged 111.6 ksi and the A-basis value was 98.0 ksi. The glass transition temperature of the unconditioned laminate was 386 °F by DMA and 380 °F by DSC.\n",
  "best_for": "Flight-heritage structural laminates where a 350 °F service range is needed (NASA tested warp tensile strength at 350 °F and 480 °F)",
  "weakest_at": "Strength and stiffness fall steeply above 350 °F and near 600 °F. Moisture lowers the glass transition temperature (NASA)",
  "identity": {
    "formula": "Woven 8H harness AS4 carbon fibre (PAN-based, 3K tows, 94.0% carbon) in a 3501-6 epoxy resin matrix; the resin chemistry is not printed in the sources read",
    "designations": [],
    "source": "nasa-tm-2000-210252",
    "where": "Section 2.1 (Materials and Processing), which names the AS4/3501-6 8H harness fabric of 3K tows; carbon content from the Hexcel AS4 datasheet, Carbon Content row"
  },
  "tags": {
    "environments": [],
    "stresses": [
      "moisture",
      "high-temperature"
    ],
    "applications": [
      "structures",
      "heat-shields"
    ]
  },
  "properties": [
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Warp tensile strength, lamina, average",
      "value": 111.6,
      "bound": "exact",
      "unit": "ksi",
      "scope": "material",
      "conditions": {
        "orientation": "warp (0 degree)",
        "form": "8H harness fabric of 3K tows, graphite/epoxy lamina",
        "temperature": "75 °F",
        "basis": "average of lots as summarised in the table",
        "test": "ASTM D 3039 (tensile), per the report Table 1"
      },
      "method": "Lamina tensile average as printed in the NASA lamina summary table",
      "status": "ground",
      "source": "nasa-tm-2000-210252",
      "where": "Table 6 (report page 18), Lamina Level Tests, Warp Tensile stress (ksi), 75 °F Average column",
      "source_detail": {
        "title": "Mechanical Property Allowables Generated for the Solid Rocket Booster Composite Nose Cap (NASA/TM-2000-210252)",
        "id": "NASA/TM-2000-210252 (A.J. Hodge, Marshall Space Flight Center, May 2000)",
        "url": "https://ntrs.nasa.gov/api/citations/20000060843/downloads/20000060843.pdf",
        "year": 2000,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Warp tensile strength, lamina, A-basis",
      "value": 98,
      "bound": "exact",
      "unit": "ksi",
      "scope": "material",
      "conditions": {
        "orientation": "warp (0 degree)",
        "form": "8H harness fabric of 3K tows, graphite/epoxy lamina",
        "temperature": "75 °F",
        "basis": "A-basis statistical allowable as printed by NASA"
      },
      "method": "A-basis lamina allowable as printed in the NASA lamina summary table",
      "status": "ground",
      "source": "nasa-tm-2000-210252",
      "where": "Table 6 (report page 18), Lamina Level Tests, Warp Tensile stress (ksi), 75 °F A-Basis column",
      "source_detail": {
        "title": "Mechanical Property Allowables Generated for the Solid Rocket Booster Composite Nose Cap (NASA/TM-2000-210252)",
        "id": "NASA/TM-2000-210252 (A.J. Hodge, Marshall Space Flight Center, May 2000)",
        "url": "https://ntrs.nasa.gov/api/citations/20000060843/downloads/20000060843.pdf",
        "year": 2000,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Fill tensile strength, lamina, average",
      "value": 104.6,
      "bound": "exact",
      "unit": "ksi",
      "scope": "material",
      "conditions": {
        "orientation": "fill (90 degree)",
        "form": "8H harness fabric of 3K tows, graphite/epoxy lamina",
        "temperature": "75 °F",
        "basis": "average of lots as summarised in the table"
      },
      "method": "Lamina tensile average as printed in the NASA lamina summary table",
      "status": "ground",
      "source": "nasa-tm-2000-210252",
      "where": "Table 6 (report page 18), Lamina Level Tests, Fill Tensile stress (ksi), 75 °F Average column",
      "source_detail": {
        "title": "Mechanical Property Allowables Generated for the Solid Rocket Booster Composite Nose Cap (NASA/TM-2000-210252)",
        "id": "NASA/TM-2000-210252 (A.J. Hodge, Marshall Space Flight Center, May 2000)",
        "url": "https://ntrs.nasa.gov/api/citations/20000060843/downloads/20000060843.pdf",
        "year": 2000,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Warp tensile strength at 350 °F (after heating to 600 °F)",
      "value": 93.9,
      "bound": "exact",
      "unit": "ksi",
      "scope": "material",
      "conditions": {
        "orientation": "warp (0 degree)",
        "temperature": "350 °F",
        "pre_treatment": "initially heated to 600 °F, then cooled to 350 °F (the report marks these samples with an asterisk)",
        "basis": "average"
      },
      "method": "Lamina tensile average as printed in the NASA lamina summary table",
      "status": "ground",
      "source": "nasa-tm-2000-210252",
      "where": "Table 6 (report page 18), Lamina Level Tests, Warp Tensile stress (ksi), 350 °F* Average column; the report defines the asterisk in the Table 6 footnotes and Section 5",
      "source_detail": {
        "title": "Mechanical Property Allowables Generated for the Solid Rocket Booster Composite Nose Cap (NASA/TM-2000-210252)",
        "id": "NASA/TM-2000-210252 (A.J. Hodge, Marshall Space Flight Center, May 2000)",
        "url": "https://ntrs.nasa.gov/api/citations/20000060843/downloads/20000060843.pdf",
        "year": 2000,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Warp tensile strength at 550 °F",
      "value": 74.8,
      "bound": "exact",
      "unit": "ksi",
      "scope": "material",
      "conditions": {
        "orientation": "warp (0 degree)",
        "temperature": "550 °F",
        "basis": "average"
      },
      "method": "Lamina tensile average as printed in the NASA lamina summary table",
      "status": "ground",
      "source": "nasa-tm-2000-210252",
      "where": "Table 6 (report page 18), Lamina Level Tests, Warp Tensile stress (ksi), 550 °F Average column",
      "source_detail": {
        "title": "Mechanical Property Allowables Generated for the Solid Rocket Booster Composite Nose Cap (NASA/TM-2000-210252)",
        "id": "NASA/TM-2000-210252 (A.J. Hodge, Marshall Space Flight Center, May 2000)",
        "url": "https://ntrs.nasa.gov/api/citations/20000060843/downloads/20000060843.pdf",
        "year": 2000,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Warp tensile strength at 480 °F",
      "value": 74.6,
      "bound": "exact",
      "unit": "ksi",
      "scope": "material",
      "conditions": {
        "orientation": "warp (0 degree)",
        "temperature": "480 °F",
        "basis": "average"
      },
      "method": "Lamina tensile average as printed in the NASA lamina summary table",
      "status": "ground",
      "source": "nasa-tm-2000-210252",
      "where": "Table 6 (report page 18), Lamina Level Tests, Warp Tensile stress (ksi), 480 °F Average column",
      "source_detail": {
        "title": "Mechanical Property Allowables Generated for the Solid Rocket Booster Composite Nose Cap (NASA/TM-2000-210252)",
        "id": "NASA/TM-2000-210252 (A.J. Hodge, Marshall Space Flight Center, May 2000)",
        "url": "https://ntrs.nasa.gov/api/citations/20000060843/downloads/20000060843.pdf",
        "year": 2000,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Warp tensile modulus, lamina, average",
      "value": 9.8,
      "bound": "exact",
      "unit": "Msi",
      "scope": "material",
      "conditions": {
        "orientation": "warp (0 degree)",
        "form": "8H harness fabric of 3K tows, graphite/epoxy lamina",
        "temperature": "75 °F",
        "basis": "average (standard deviation 0.4 Msi printed alongside)"
      },
      "method": "Lamina modulus average as printed in the NASA lamina summary table",
      "status": "ground",
      "source": "nasa-tm-2000-210252",
      "where": "Table 6 (report page 18), second lamina table, Warp Tensile modulus (Msi), 75 °F Average column",
      "source_detail": {
        "title": "Mechanical Property Allowables Generated for the Solid Rocket Booster Composite Nose Cap (NASA/TM-2000-210252)",
        "id": "NASA/TM-2000-210252 (A.J. Hodge, Marshall Space Flight Center, May 2000)",
        "url": "https://ntrs.nasa.gov/api/citations/20000060843/downloads/20000060843.pdf",
        "year": 2000,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Fill tensile modulus, lamina, average",
      "value": 9.7,
      "bound": "exact",
      "unit": "Msi",
      "scope": "material",
      "conditions": {
        "orientation": "fill (90 degree)",
        "form": "8H harness fabric of 3K tows, graphite/epoxy lamina",
        "temperature": "75 °F",
        "basis": "average (standard deviation 0.4 Msi printed alongside)"
      },
      "method": "Lamina modulus average as printed in the NASA lamina summary table",
      "status": "ground",
      "source": "nasa-tm-2000-210252",
      "where": "Table 6 (report page 18), second lamina table, Fill Tensile modulus (Msi), 75 °F Average column",
      "source_detail": {
        "title": "Mechanical Property Allowables Generated for the Solid Rocket Booster Composite Nose Cap (NASA/TM-2000-210252)",
        "id": "NASA/TM-2000-210252 (A.J. Hodge, Marshall Space Flight Center, May 2000)",
        "url": "https://ntrs.nasa.gov/api/citations/20000060843/downloads/20000060843.pdf",
        "year": 2000,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "compressive_strength",
      "label": "Warp compressive strength, lamina, average",
      "value": 82.9,
      "bound": "exact",
      "unit": "ksi",
      "scope": "material",
      "conditions": {
        "orientation": "warp (0 degree)",
        "form": "8H harness fabric of 3K tows, graphite/epoxy lamina",
        "temperature": "75 °F",
        "basis": "average"
      },
      "method": "Lamina compression average as printed in the NASA lamina summary table (ASTM D 695 per Table 1)",
      "status": "ground",
      "source": "nasa-tm-2000-210252",
      "where": "Table 6 (report page 18), Lamina Level Tests, Warp Compr. stress (ksi), 75 °F Average column",
      "source_detail": {
        "title": "Mechanical Property Allowables Generated for the Solid Rocket Booster Composite Nose Cap (NASA/TM-2000-210252)",
        "id": "NASA/TM-2000-210252 (A.J. Hodge, Marshall Space Flight Center, May 2000)",
        "url": "https://ntrs.nasa.gov/api/citations/20000060843/downloads/20000060843.pdf",
        "year": 2000,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "compressive_modulus",
      "label": "Warp compressive modulus, lamina, average",
      "value": 8.7,
      "bound": "exact",
      "unit": "Msi",
      "scope": "material",
      "conditions": {
        "orientation": "warp (0 degree)",
        "form": "8H harness fabric of 3K tows, graphite/epoxy lamina",
        "temperature": "75 °F",
        "basis": "average (standard deviation 0.7 Msi printed alongside)"
      },
      "method": "Lamina modulus average as printed in the NASA lamina summary table",
      "status": "ground",
      "source": "nasa-tm-2000-210252",
      "where": "Table 6 (report page 18), second lamina table, Warp Compr. modulus (Msi), 75 °F Average column",
      "source_detail": {
        "title": "Mechanical Property Allowables Generated for the Solid Rocket Booster Composite Nose Cap (NASA/TM-2000-210252)",
        "id": "NASA/TM-2000-210252 (A.J. Hodge, Marshall Space Flight Center, May 2000)",
        "url": "https://ntrs.nasa.gov/api/citations/20000060843/downloads/20000060843.pdf",
        "year": 2000,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "in_plane_shear_strength",
      "label": "In-plane shear strength, +45 degree lamina, average",
      "value": 13.3,
      "bound": "exact",
      "unit": "ksi",
      "scope": "material",
      "conditions": {
        "orientation": "+45 degree (balanced biaxial laminate)",
        "form": "8H harness fabric of 3K tows, graphite/epoxy lamina",
        "temperature": "75 °F",
        "basis": "average"
      },
      "method": "Lamina in-plane shear average as printed in the NASA lamina summary table (ASTM D 3518 per Table 1)",
      "status": "ground",
      "source": "nasa-tm-2000-210252",
      "where": "Table 6 (report page 18), Lamina Level Tests, 45 In-Plane shear (ksi), 75 °F Average column",
      "source_detail": {
        "title": "Mechanical Property Allowables Generated for the Solid Rocket Booster Composite Nose Cap (NASA/TM-2000-210252)",
        "id": "NASA/TM-2000-210252 (A.J. Hodge, Marshall Space Flight Center, May 2000)",
        "url": "https://ntrs.nasa.gov/api/citations/20000060843/downloads/20000060843.pdf",
        "year": 2000,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "shear_modulus",
      "label": "In-plane shear modulus, +45 degree lamina, average",
      "value": 730.5,
      "bound": "exact",
      "unit": "ksi",
      "scope": "material",
      "conditions": {
        "orientation": "+45 degree (balanced biaxial laminate)",
        "form": "8H harness fabric of 3K tows, graphite/epoxy lamina",
        "temperature": "75 °F",
        "basis": "average (standard deviation 56.0 ksi printed alongside)"
      },
      "method": "Lamina shear modulus average as printed in the NASA lamina summary table",
      "status": "ground",
      "source": "nasa-tm-2000-210252",
      "where": "Table 6 (report page 18), second lamina table, 45 Shear modulus (ksi), 75 °F Average column",
      "source_detail": {
        "title": "Mechanical Property Allowables Generated for the Solid Rocket Booster Composite Nose Cap (NASA/TM-2000-210252)",
        "id": "NASA/TM-2000-210252 (A.J. Hodge, Marshall Space Flight Center, May 2000)",
        "url": "https://ntrs.nasa.gov/api/citations/20000060843/downloads/20000060843.pdf",
        "year": 2000,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "interlaminar_shear_strength",
      "label": "Warp interlaminar shear strength, average",
      "value": 7040,
      "bound": "exact",
      "unit": "psi",
      "scope": "material",
      "conditions": {
        "orientation": "warp (0 degree)",
        "form": "8H harness fabric of 3K tows, graphite/epoxy lamina",
        "temperature": "75 °F",
        "basis": "average (ASTM D 3846 per Table 1)"
      },
      "method": "Lamina interlaminar shear average as printed in the NASA lamina summary table",
      "status": "ground",
      "source": "nasa-tm-2000-210252",
      "where": "Table 6 (report page 18), Lamina Level Tests, Warp Interlaminar shear (psi), 75 °F Average column",
      "source_detail": {
        "title": "Mechanical Property Allowables Generated for the Solid Rocket Booster Composite Nose Cap (NASA/TM-2000-210252)",
        "id": "NASA/TM-2000-210252 (A.J. Hodge, Marshall Space Flight Center, May 2000)",
        "url": "https://ntrs.nasa.gov/api/citations/20000060843/downloads/20000060843.pdf",
        "year": 2000,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "poissons_ratio",
      "label": "Warp Poisson's ratio, lamina",
      "value": 0.06,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "orientation": "warp (0 degree)",
        "form": "8H harness fabric of 3K tows, graphite/epoxy lamina",
        "temperature": "75 °F",
        "basis": "printed in the 75 °F column of the lamina table; the column is not labelled average or A-basis"
      },
      "method": "Value printed in the NASA lamina summary table",
      "status": "ground",
      "source": "nasa-tm-2000-210252",
      "where": "Table 6 (report page 18), Lamina Level Tests, Warp Poisson's ratio row",
      "source_detail": {
        "title": "Mechanical Property Allowables Generated for the Solid Rocket Booster Composite Nose Cap (NASA/TM-2000-210252)",
        "id": "NASA/TM-2000-210252 (A.J. Hodge, Marshall Space Flight Center, May 2000)",
        "url": "https://ntrs.nasa.gov/api/citations/20000060843/downloads/20000060843.pdf",
        "year": 2000,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "poissons_ratio",
      "label": "Fill Poisson's ratio, lamina",
      "value": 0.07,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "orientation": "fill (90 degree)",
        "form": "8H harness fabric of 3K tows, graphite/epoxy lamina",
        "temperature": "75 °F",
        "basis": "printed in the 75 °F column of the lamina table; the column is not labelled average or A-basis"
      },
      "method": "Value printed in the NASA lamina summary table",
      "status": "ground",
      "source": "nasa-tm-2000-210252",
      "where": "Table 6 (report page 18), Lamina Level Tests, Fill Poisson's ratio row",
      "source_detail": {
        "title": "Mechanical Property Allowables Generated for the Solid Rocket Booster Composite Nose Cap (NASA/TM-2000-210252)",
        "id": "NASA/TM-2000-210252 (A.J. Hodge, Marshall Space Flight Center, May 2000)",
        "url": "https://ntrs.nasa.gov/api/citations/20000060843/downloads/20000060843.pdf",
        "year": 2000,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "glass_transition_temperature",
      "label": "Glass transition temperature, unconditioned, DMA",
      "value": 386,
      "bound": "exact",
      "unit": "°F",
      "scope": "material",
      "conditions": {
        "state": "unconditioned ambient laminate",
        "method_detail": "dynamic mechanical analyzer (DMA)"
      },
      "method": "Measured by DMA as printed in Section 2.3 (Moisture Conditioning) of the NASA report",
      "status": "ground",
      "source": "nasa-tm-2000-210252",
      "where": "Section 2.3 (Moisture Conditioning), Tg paragraph; the paragraph says the ambient samples had Tg values of 386 and 380 °F from DMA and DSC",
      "source_detail": {
        "title": "Mechanical Property Allowables Generated for the Solid Rocket Booster Composite Nose Cap (NASA/TM-2000-210252)",
        "id": "NASA/TM-2000-210252 (A.J. Hodge, Marshall Space Flight Center, May 2000)",
        "url": "https://ntrs.nasa.gov/api/citations/20000060843/downloads/20000060843.pdf",
        "year": 2000,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "glass_transition_temperature",
      "label": "Glass transition temperature, unconditioned, DSC",
      "value": 380,
      "bound": "exact",
      "unit": "°F",
      "scope": "material",
      "conditions": {
        "state": "unconditioned ambient laminate",
        "method_detail": "dynamic scanning calorimeter (DSC)"
      },
      "method": "Measured by DSC as printed in Section 2.3 (Moisture Conditioning) of the NASA report",
      "status": "ground",
      "source": "nasa-tm-2000-210252",
      "where": "Section 2.3 (Moisture Conditioning), Tg paragraph",
      "source_detail": {
        "title": "Mechanical Property Allowables Generated for the Solid Rocket Booster Composite Nose Cap (NASA/TM-2000-210252)",
        "id": "NASA/TM-2000-210252 (A.J. Hodge, Marshall Space Flight Center, May 2000)",
        "url": "https://ntrs.nasa.gov/api/citations/20000060843/downloads/20000060843.pdf",
        "year": 2000,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "glass_transition_temperature",
      "label": "Glass transition temperature, dry, DMA",
      "value": 398,
      "bound": "exact",
      "unit": "°F",
      "scope": "material",
      "conditions": {
        "state": "dried for 24 hr at 250 °F before test (the report calls this the initial dry Tg)",
        "method_detail": "dynamic mechanical analyzer (DMA)"
      },
      "method": "Measured by DMA as printed in Section 2.3 (Moisture Conditioning) of the NASA report",
      "status": "ground",
      "source": "nasa-tm-2000-210252",
      "where": "Section 2.3 (Moisture Conditioning), Tg paragraph",
      "source_detail": {
        "title": "Mechanical Property Allowables Generated for the Solid Rocket Booster Composite Nose Cap (NASA/TM-2000-210252)",
        "id": "NASA/TM-2000-210252 (A.J. Hodge, Marshall Space Flight Center, May 2000)",
        "url": "https://ntrs.nasa.gov/api/citations/20000060843/downloads/20000060843.pdf",
        "year": 2000,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "fiber_volume_fraction",
      "label": "Fibre volume of the cured graphite/epoxy laminate",
      "value": 59.9,
      "value_high": 62.7,
      "bound": "range",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "laminate": "6-, 8- and 10-ply AS4/3501-6 laminates (per-laminate values 59.9, 62.7 and 61.6 percent)",
        "method_detail": "acid digestion of the matrix, ASTM D 3171 Procedure A (nitric acid)"
      },
      "method": "Measured by acid digestion and reported as printed in the NASA report",
      "status": "ground",
      "source": "nasa-tm-2000-210252",
      "where": "Section 2.1 (Materials and Processing), acid digestion paragraph",
      "source_detail": {
        "title": "Mechanical Property Allowables Generated for the Solid Rocket Booster Composite Nose Cap (NASA/TM-2000-210252)",
        "id": "NASA/TM-2000-210252 (A.J. Hodge, Marshall Space Flight Center, May 2000)",
        "url": "https://ntrs.nasa.gov/api/citations/20000060843/downloads/20000060843.pdf",
        "year": 2000,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "fabric_areal_weight",
      "label": "Areal weight of the 8H AS4/3501-6 fabric",
      "value": 370,
      "bound": "exact",
      "unit": "g/m2",
      "scope": "material",
      "conditions": {
        "form": "AS4 3K tow 8H harness fabric, as used for the SRB nose cap"
      },
      "method": "Value printed in the NASA report",
      "status": "ground",
      "source": "nasa-tm-2000-210252",
      "where": "Section 2.1 (Materials and Processing), acid digestion paragraph (fabric aerial weight, printed as 370 g/m2)",
      "source_detail": {
        "title": "Mechanical Property Allowables Generated for the Solid Rocket Booster Composite Nose Cap (NASA/TM-2000-210252)",
        "id": "NASA/TM-2000-210252 (A.J. Hodge, Marshall Space Flight Center, May 2000)",
        "url": "https://ntrs.nasa.gov/api/citations/20000060843/downloads/20000060843.pdf",
        "year": 2000,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "AS4 carbon fibre tow tensile strength (fibre, not laminate)",
      "value": 4433,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "form": "HexTow AS4 carbon fibre tow, PAN-based, 3K, 6K and 12K counts",
        "basis": "typical fibre property; printed as 643 ksi (4,433 MPa)",
        "test": "not printed on the datasheet"
      },
      "method": "Typical fibre property from the Hexcel AS4 product data sheet (fibre, not the laminate)",
      "status": "ground",
      "source": "hexcel-as4-datasheet",
      "where": "Typical Fiber Properties table, Tensile Strength row",
      "source_detail": {
        "title": "HexTow AS4 Carbon Fiber Product Data Sheet (Hexcel Corporation, March 2010), copy hosted by Rockwest Composites",
        "id": "Hexcel HexTow AS4 Product Data, March 2010",
        "url": "https://www.rockwestcomposites.com/on/demandware.static/Sites-RWC-Site/Sites-rwc-master-catalog/-/wysiwyg/AS4.pdf",
        "year": 2010,
        "kind": "datasheet",
        "license": "supplier document, linked not reproduced"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "AS4 carbon fibre tow tensile modulus (fibre, not laminate)",
      "value": 231,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "form": "HexTow AS4 carbon fibre tow",
        "basis": "typical fibre property; printed as 33.5 Msi (231 GPa), chord 6000-1000"
      },
      "method": "Typical fibre property from the Hexcel AS4 product data sheet (fibre, not the laminate)",
      "status": "ground",
      "source": "hexcel-as4-datasheet",
      "where": "Typical Fiber Properties table, Tensile Modulus (Chord 6000-1000) row",
      "source_detail": {
        "title": "HexTow AS4 Carbon Fiber Product Data Sheet (Hexcel Corporation, March 2010), copy hosted by Rockwest Composites",
        "id": "Hexcel HexTow AS4 Product Data, March 2010",
        "url": "https://www.rockwestcomposites.com/on/demandware.static/Sites-RWC-Site/Sites-rwc-master-catalog/-/wysiwyg/AS4.pdf",
        "year": 2010,
        "kind": "datasheet",
        "license": "supplier document, linked not reproduced"
      }
    },
    {
      "benchmark": "elongation",
      "label": "AS4 carbon fibre tow ultimate elongation (fibre, not laminate)",
      "value": 1.8,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "form": "HexTow AS4 carbon fibre tow"
      },
      "method": "Typical fibre property from the Hexcel AS4 product data sheet",
      "status": "ground",
      "source": "hexcel-as4-datasheet",
      "where": "Typical Fiber Properties table, Ultimate Elongation at Failure row",
      "source_detail": {
        "title": "HexTow AS4 Carbon Fiber Product Data Sheet (Hexcel Corporation, March 2010), copy hosted by Rockwest Composites",
        "id": "Hexcel HexTow AS4 Product Data, March 2010",
        "url": "https://www.rockwestcomposites.com/on/demandware.static/Sites-RWC-Site/Sites-rwc-master-catalog/-/wysiwyg/AS4.pdf",
        "year": 2010,
        "kind": "datasheet",
        "license": "supplier document, linked not reproduced"
      }
    },
    {
      "benchmark": "density",
      "label": "AS4 carbon fibre density (fibre, not laminate)",
      "value": 1.79,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "form": "HexTow AS4 carbon fibre",
        "basis": "printed as 0.0647 lb/in3 (1.79 g/cm3)"
      },
      "method": "Typical fibre property from the Hexcel AS4 product data sheet",
      "status": "ground",
      "source": "hexcel-as4-datasheet",
      "where": "Typical Fiber Properties table, Density row",
      "source_detail": {
        "title": "HexTow AS4 Carbon Fiber Product Data Sheet (Hexcel Corporation, March 2010), copy hosted by Rockwest Composites",
        "id": "Hexcel HexTow AS4 Product Data, March 2010",
        "url": "https://www.rockwestcomposites.com/on/demandware.static/Sites-RWC-Site/Sites-rwc-master-catalog/-/wysiwyg/AS4.pdf",
        "year": 2010,
        "kind": "datasheet",
        "license": "supplier document, linked not reproduced"
      }
    },
    {
      "benchmark": "cte",
      "label": "AS4 carbon fibre coefficient of thermal expansion (fibre, not laminate)",
      "value": -0.63,
      "bound": "exact",
      "unit": "ppm/ºC",
      "scope": "material",
      "conditions": {
        "form": "HexTow AS4 carbon fibre yarn",
        "basis": "printed as -0.35 ppm/ºF (-0.63 ppm/ºC)",
        "direction": "not stated on the datasheet"
      },
      "method": "Typical yarn property from the Hexcel AS4 product data sheet",
      "status": "ground",
      "source": "hexcel-as4-datasheet",
      "where": "Yarn/Tow Characteristics table, Coefficient of Thermal Expansion row",
      "source_detail": {
        "title": "HexTow AS4 Carbon Fiber Product Data Sheet (Hexcel Corporation, March 2010), copy hosted by Rockwest Composites",
        "id": "Hexcel HexTow AS4 Product Data, March 2010",
        "url": "https://www.rockwestcomposites.com/on/demandware.static/Sites-RWC-Site/Sites-rwc-master-catalog/-/wysiwyg/AS4.pdf",
        "year": 2010,
        "kind": "datasheet",
        "license": "supplier document, linked not reproduced"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "label": "AS4 carbon fibre thermal conductivity (fibre, not laminate)",
      "value": 6.83,
      "bound": "exact",
      "unit": "W/m-ºK",
      "scope": "material",
      "conditions": {
        "form": "HexTow AS4 carbon fibre yarn",
        "basis": "printed as 3.95 Btu/hr-ft-ºF (6.83 W/m-ºK)"
      },
      "method": "Typical yarn property from the Hexcel AS4 product data sheet",
      "status": "ground",
      "source": "hexcel-as4-datasheet",
      "where": "Yarn/Tow Characteristics table, Thermal Conductivity row",
      "source_detail": {
        "title": "HexTow AS4 Carbon Fiber Product Data Sheet (Hexcel Corporation, March 2010), copy hosted by Rockwest Composites",
        "id": "Hexcel HexTow AS4 Product Data, March 2010",
        "url": "https://www.rockwestcomposites.com/on/demandware.static/Sites-RWC-Site/Sites-rwc-master-catalog/-/wysiwyg/AS4.pdf",
        "year": 2010,
        "kind": "datasheet",
        "license": "supplier document, linked not reproduced"
      }
    },
    {
      "benchmark": "specific_heat",
      "label": "AS4 carbon fibre specific heat (fibre, not laminate)",
      "value": 0.27,
      "bound": "exact",
      "unit": "cal/g-°C",
      "scope": "material",
      "conditions": {
        "form": "HexTow AS4 carbon fibre yarn",
        "basis": "printed as 0.279 Btu/lb-°F (0.27 cal/g-°C)"
      },
      "method": "Typical yarn property from the Hexcel AS4 product data sheet",
      "status": "ground",
      "source": "hexcel-as4-datasheet",
      "where": "Yarn/Tow Characteristics table, Specific Heat row",
      "source_detail": {
        "title": "HexTow AS4 Carbon Fiber Product Data Sheet (Hexcel Corporation, March 2010), copy hosted by Rockwest Composites",
        "id": "Hexcel HexTow AS4 Product Data, March 2010",
        "url": "https://www.rockwestcomposites.com/on/demandware.static/Sites-RWC-Site/Sites-rwc-master-catalog/-/wysiwyg/AS4.pdf",
        "year": 2010,
        "kind": "datasheet",
        "license": "supplier document, linked not reproduced"
      }
    },
    {
      "benchmark": "electrical_resistivity",
      "label": "AS4 carbon fibre electrical resistivity (fibre, not laminate)",
      "value": 0.0017,
      "bound": "exact",
      "unit": "ohm-cm",
      "scope": "material",
      "conditions": {
        "form": "HexTow AS4 carbon fibre yarn",
        "basis": "printed as 5.6 x 10-5 ohm-ft (1.7 x 10-3 ohm-cm)"
      },
      "method": "Typical yarn property from the Hexcel AS4 product data sheet",
      "status": "ground",
      "source": "hexcel-as4-datasheet",
      "where": "Yarn/Tow Characteristics table, Electrical Resistivity row",
      "source_detail": {
        "title": "HexTow AS4 Carbon Fiber Product Data Sheet (Hexcel Corporation, March 2010), copy hosted by Rockwest Composites",
        "id": "Hexcel HexTow AS4 Product Data, March 2010",
        "url": "https://www.rockwestcomposites.com/on/demandware.static/Sites-RWC-Site/Sites-rwc-master-catalog/-/wysiwyg/AS4.pdf",
        "year": 2010,
        "kind": "datasheet",
        "license": "supplier document, linked not reproduced"
      }
    },
    {
      "benchmark": "filament_diameter",
      "label": "AS4 carbon filament diameter",
      "value": 7.1,
      "bound": "exact",
      "unit": "microns",
      "scope": "material",
      "conditions": {
        "form": "HexTow AS4 carbon fibre filament",
        "basis": "printed as 0.280 mil (7.1 microns)"
      },
      "method": "Typical fibre property from the Hexcel AS4 product data sheet",
      "status": "ground",
      "source": "hexcel-as4-datasheet",
      "where": "Typical Fiber Properties table, Filament Diameter row",
      "source_detail": {
        "title": "HexTow AS4 Carbon Fiber Product Data Sheet (Hexcel Corporation, March 2010), copy hosted by Rockwest Composites",
        "id": "Hexcel HexTow AS4 Product Data, March 2010",
        "url": "https://www.rockwestcomposites.com/on/demandware.static/Sites-RWC-Site/Sites-rwc-master-catalog/-/wysiwyg/AS4.pdf",
        "year": 2010,
        "kind": "datasheet",
        "license": "supplier document, linked not reproduced"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Transverse tensile strength, unidirectional lamina, 22 °C, dry, high strain rate",
      "value": 59.3,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "orientation": "transverse (90 degree)",
        "form": "unidirectional AS4/3501-6 graphite/epoxy, not the 8H fabric",
        "temperature": "22 °C (72 °F)",
        "moisture": "0 %",
        "strain_rate": "high"
      },
      "method": "Average transverse tensile strength as printed in NASA CR-187229 Table 5.1",
      "status": "ground",
      "source": "nasa-cr-187229",
      "where": "Table 5.1, Average transverse tensile properties for unidirectional AS4/3501-6, Transverse Tensile Strength row, High strain rate, 0% moisture 22 C column (printed as 59.3 MPa with 8.60 ksi)",
      "source_detail": {
        "title": "Environmental and Strain Rate Effects on Graphite/Epoxy Composites (NASA CR-187229)",
        "id": "NASA CR-187229, Konstantinos Peimandis, Northwestern University, October 1991 (NTRS 19920011242)",
        "url": "https://ntrs.nasa.gov/api/citations/19920011242/downloads/19920011242.pdf",
        "year": 1991,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Transverse tensile strength, unidirectional lamina, 22 °C, 1% moisture, high strain rate",
      "value": 40.8,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "orientation": "transverse (90 degree)",
        "form": "unidirectional AS4/3501-6 graphite/epoxy, not the 8H fabric",
        "temperature": "22 °C (72 °F)",
        "moisture": "1 %",
        "strain_rate": "high"
      },
      "method": "Average transverse tensile strength as printed in NASA CR-187229 Table 5.1",
      "status": "ground",
      "source": "nasa-cr-187229",
      "where": "Table 5.1, Average transverse tensile properties for unidirectional AS4/3501-6, Transverse Tensile Strength row, High strain rate, 1% MOISTURE 22 C column (printed as 40.8 MPa with 5.92 ksi)",
      "source_detail": {
        "title": "Environmental and Strain Rate Effects on Graphite/Epoxy Composites (NASA CR-187229)",
        "id": "NASA CR-187229, Konstantinos Peimandis, Northwestern University, October 1991 (NTRS 19920011242)",
        "url": "https://ntrs.nasa.gov/api/citations/19920011242/downloads/19920011242.pdf",
        "year": 1991,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Transverse tensile modulus E22, unidirectional lamina, 22 °C, dry, high strain rate",
      "value": 11.9,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "orientation": "transverse (90 degree)",
        "form": "unidirectional AS4/3501-6 graphite/epoxy, not the 8H fabric",
        "temperature": "22 °C (72 °F)",
        "moisture": "0 %",
        "strain_rate": "high"
      },
      "method": "Average transverse tensile modulus as printed in NASA CR-187229 Table 5.1",
      "status": "ground",
      "source": "nasa-cr-187229",
      "where": "Table 5.1, Average transverse tensile properties, Transverse Modulus E22 row, High strain rate, 0% moisture 22 C column (printed as 11.9 GPa with 1.73 Msi)",
      "source_detail": {
        "title": "Environmental and Strain Rate Effects on Graphite/Epoxy Composites (NASA CR-187229)",
        "id": "NASA CR-187229, Konstantinos Peimandis, Northwestern University, October 1991 (NTRS 19920011242)",
        "url": "https://ntrs.nasa.gov/api/citations/19920011242/downloads/19920011242.pdf",
        "year": 1991,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Transverse tensile modulus E22, unidirectional lamina, 22 °C, dry, low strain rate",
      "value": 10,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "orientation": "transverse (90 degree)",
        "form": "unidirectional AS4/3501-6 graphite/epoxy, not the 8H fabric",
        "temperature": "22 °C (72 °F)",
        "moisture": "0 %",
        "strain_rate": "low"
      },
      "method": "Average transverse tensile modulus as printed in NASA CR-187229 Table 5.1",
      "status": "ground",
      "source": "nasa-cr-187229",
      "where": "Table 5.1, Average transverse tensile properties, Transverse Modulus E22 row, Low strain rate, 0% moisture 22 C column (printed as 10.0 GPa with 1.45 Msi)",
      "source_detail": {
        "title": "Environmental and Strain Rate Effects on Graphite/Epoxy Composites (NASA CR-187229)",
        "id": "NASA CR-187229, Konstantinos Peimandis, Northwestern University, October 1991 (NTRS 19920011242)",
        "url": "https://ntrs.nasa.gov/api/citations/19920011242/downloads/19920011242.pdf",
        "year": 1991,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "moisture_absorption",
      "label": "Equilibrium moisture content, [90s] unidirectional specimen, in water at 49 °C",
      "value": 1.41,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "orientation": "[90s] unidirectional",
        "form": "unidirectional AS4/3501-6 graphite/epoxy",
        "environment": "immersion in water at 49 °C (120 °F)",
        "basis": "equilibrium value as stated by the report; the report says the absorption curves had not reached equilibrium in its test"
      },
      "method": "Moisture weight gain of the embedded-gauge specimen, reported as equilibrium moisture content in NASA CR-187229 section 5.1.1",
      "status": "ground",
      "source": "nasa-cr-187229",
      "where": "Section 5.1.1, Moisture Absorption Evaluation Results, text for the [90s] specimen (equilibrium moisture content of 1.41 %), Figure 5.2 data",
      "source_detail": {
        "title": "Environmental and Strain Rate Effects on Graphite/Epoxy Composites (NASA CR-187229)",
        "id": "NASA CR-187229, Konstantinos Peimandis, Northwestern University, October 1991 (NTRS 19920011242)",
        "url": "https://ntrs.nasa.gov/api/citations/19920011242/downloads/19920011242.pdf",
        "year": 1991,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "moisture_absorption",
      "label": "Equilibrium moisture content, [0s] unidirectional specimen, in water at 49 °C",
      "value": 1.34,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "orientation": "[0s] unidirectional",
        "form": "unidirectional AS4/3501-6 graphite/epoxy",
        "environment": "immersion in water at 49 °C (120 °F)",
        "basis": "equilibrium value as stated by the report; the report says the absorption curves had not reached equilibrium in its test"
      },
      "method": "Moisture weight gain of the embedded-gauge specimen, reported as equilibrium moisture content in NASA CR-187229 section 5.1.1",
      "status": "ground",
      "source": "nasa-cr-187229",
      "where": "Section 5.1.1, Moisture Absorption Evaluation Results, text for the [0s] specimen (equilibrium moisture content of 1.34%), Figure 5.2 data",
      "source_detail": {
        "title": "Environmental and Strain Rate Effects on Graphite/Epoxy Composites (NASA CR-187229)",
        "id": "NASA CR-187229, Konstantinos Peimandis, Northwestern University, October 1991 (NTRS 19920011242)",
        "url": "https://ntrs.nasa.gov/api/citations/19920011242/downloads/19920011242.pdf",
        "year": 1991,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Moist heat: 180 °F and 93% relative humidity (the test-coupon conditioning the NASA report used)",
      "headline": "Moisture lowers the glass transition temperature of AS4/3501-6, mostly within the first 10 days of exposure at 180 °F and 93% RH.",
      "effect": "The NASA report says the major loss in Tg occurs in the first 10 days at 180 °F and 93% RH, and that Tg begins to plateau after about 20 days. The Tg values for the conditioned laminate are shown in the report figures only. The unconditioned dry Tg was 398 °F by DMA. The report says all AS4/3501-6 test coupons were conditioned for 10 days at 180 °F and 93% RH, and that this exposure was sufficient.",
      "rating": "moderate",
      "conditions": {
        "exposure": "180 °F and 93% relative humidity",
        "time": "10 days (major Tg loss) to about 20 days (plateau), per the report text",
        "laminate": "six-ply composite for the Tg-versus-time test"
      },
      "source": "nasa-tm-2000-210252",
      "where": "Section 2.3 (Moisture Conditioning), Tg paragraph and Figure 4; Section 6 (Conclusions)"
    },
    {
      "environment": "Moisture uptake at 180 °F and 93% RH (predicted 10-day soak)",
      "headline": "The report predicts a 10-day soak at 180 °F and 93% RH gives 0.9%, 0.75% and 0.6% moisture gain for 6-, 8- and 10-ply laminates.",
      "effect": "These weight gains are predicted from a diffusion model and checked against conditioned test specimens. The report says the measured weight gains matched the predicted gains, and that beach exposure panels gained less weight than the test specimens.",
      "rating": "moderate",
      "conditions": {
        "exposure": "180 °F and 93% relative humidity",
        "time": "10 days",
        "laminates": "6-, 8- and 10-ply AS4/3501-6, values as printed",
        "basis": "predicted in the report from the diffusion model (printed as should result in)"
      },
      "source": "nasa-tm-2000-210252",
      "where": "Section 2.3 (Moisture Conditioning), paragraph after Figure 6; Section 6 (Conclusions)"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "The Hexcel AS4 product data sheet tells users to obtain, read and understand the safety data sheet before use. No safety data sheet for AS4/3501-6 was read for this profile, so no GHS or hazard classification is stated here.",
        "ghs": [],
        "source": "hexcel-as4-datasheet",
        "where": "Safety Information section"
      }
    ],
    "failure_risks": [
      {
        "mode": "Loss of glass transition temperature after moisture uptake",
        "trigger": "Exposure to 180 °F and 93% relative humidity",
        "consequence": "Tg falls with moisture uptake, with most of the loss in the first 10 days, so the usable high-temperature limit drops. The report says the moisture-conditioned composite would also change with exposure time at 600 °F, which is well above the Tg.",
        "severity": "moderate",
        "source": "nasa-tm-2000-210252",
        "where": "Section 2.3 (Moisture Conditioning) and the discussion of baking at 600 °F in Section 4"
      },
      {
        "mode": "Fibre misalignment in fabrication",
        "trigger": "Lot 2 prepreg, identified during tensile testing",
        "consequence": "Some specimens had fill misalignment as high as 6 degrees on as many as half the plies. This misalignment affected the high-temperature tensile fill results and gave large scatter in strength and modulus between panels.",
        "severity": "moderate",
        "source": "nasa-tm-2000-210252",
        "where": "Section 5 (Test Results), first paragraph"
      },
      {
        "mode": "Moisture lowers transverse tensile strength of unidirectional AS4/3501-6",
        "trigger": "1% moisture content at 22 °C (72 °F), high strain rate",
        "consequence": "In NASA CR-187229 Table 5.1, high strain rate transverse tensile strength at 22 °C fell from 59.3 MPa at 0% moisture to 40.8 MPa at 1% moisture. The unidirectional tape values are kept separate from the 8H fabric values.",
        "severity": "moderate",
        "source": "nasa-cr-187229",
        "where": "Table 5.1, Average transverse tensile properties for unidirectional AS4/3501-6"
      },
      {
        "mode": "Notch sensitivity of tape laminates",
        "trigger": "Open-hole tension on the multi-angle tape laminates tested, with one hole size",
        "consequence": "NASA CR-4610 states that the tape laminates showed some notch sensitivity. Table 3.1 gives unnotched and open-hole tension strengths for the laminate layups, which are not the 8H fabric in the rows above.",
        "severity": "moderate",
        "source": "nasa-cr-4610",
        "where": "Section 3 (tension) text on notch sensitivity, and Table 3.1 Laminate Longitudinal Tension Properties"
      },
      {
        "mode": "Delamination from low through-thickness strength",
        "trigger": "Geometric or material discontinuities in the laminate, and impact (Figure 2 is a compression-after-impact result)",
        "consequence": "NASA/TM-2010-216869 states that composites have low through-thickness strength, so delaminations can start and grow, and that delaminations degrade the strength of the laminate. Its Figure 2 gives compression-after-impact strength for AS4/3501-6 from NASA Langley test data.",
        "severity": "moderate",
        "source": "nasa-tm-2010-216869",
        "where": "Body text on delamination, and the Figure 2 caption naming AS4/3501-6"
      }
    ],
    "side_effects": [],
    "handling": [
      {
        "text": "Condition wet test coupons at 180 °F and 93% RH for 10 days. The NASA report found this exposure sufficient for the moisture absorption of the composite.",
        "source": "nasa-tm-2000-210252",
        "where": "Section 6 (Conclusions)"
      },
      {
        "text": "For spacecraft use, screen the laminate in vacuum outgassing. NASA's outgassing database reports total mass loss and collected volatile condensable material from the ASTM E 595 test. No AS4/3501-6 record was read in this run.",
        "source": "nasa-outgassing-guide",
        "where": "User guide, description of the test method and of the database sections"
      }
    ],
    "mitigations": [
      {
        "text": "The report notes that the Hypalon coating tried as a moisture barrier was ineffective: the coated specimens gained about the same moisture as the uncoated composite. Material properties therefore had to be developed in the wet state.",
        "source": "nasa-tm-2000-210252",
        "where": "Section 2.3 (Moisture Conditioning)"
      }
    ]
  },
  "uses": [
    {
      "application": "structures",
      "device": "Space Shuttle solid rocket booster composite nose cap (NASA and USBI development, to replace a metallic TPS-coated nose cap)",
      "example": "Two facesheets of AS4/3501-6 graphite/epoxy encapsulate a core of Scotch-Core SC350G syntactic foam, cocured in an autoclave for 4 hr at 375 °F and 85 psig.",
      "source": "nasa-tm-2000-210252",
      "where": "Section 1 (Introduction) and Section 2.1 (Materials and Processing)"
    },
    {
      "application": "structures",
      "device": "Woven, prepregged, wound or braided composite parts made from HexTow AS4 fibre (general product use)",
      "example": "Hexcel suggests HexTow AS4 for weaving, prepregging, filament winding, braiding and pultrusion. This is the fibre product use, not a use specific to the 3501-6 resin.",
      "source": "hexcel-as4-datasheet",
      "where": "Product description paragraph, first page"
    }
  ],
  "supply": [
    {
      "subject": "PAN-based carbon fibre (AS4 tow)",
      "abundance": "Not applicable: a synthetic fibre made from a polyacrylonitrile (PAN) precursor, so no crustal abundance applies",
      "producers": [],
      "critical_lists": [],
      "recycling": "Not found in the sources read for this profile.",
      "substitutes": [],
      "source": "hexcel-10k-fy2024",
      "where": "Item 1 Business, Raw Materials and Production Activities; Research and Technology, Patents and Know-How (Salt Lake City sentence)"
    },
    {
      "subject": "Acrylonitrile (primary raw material for the PAN precursor)",
      "abundance": "Not found in the sources read for this profile.",
      "producers": [],
      "critical_lists": [],
      "recycling": "Not found in the sources read for this profile.",
      "substitutes": [],
      "source": "hexcel-10k-fy2024",
      "where": "Item 1 Business, Raw Materials and Production Activities"
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "Mechanical Property Allowables Generated for the Solid Rocket Booster Composite Nose Cap (NASA/TM-2000-210252)",
      "type": "report",
      "url": "https://ntrs.nasa.gov/api/citations/20000060843/downloads/20000060843.pdf",
      "year": 2000
    },
    {
      "title": "HexTow AS4 Carbon Fiber Product Data Sheet (Hexcel, March 2010), copy hosted by Rockwest Composites",
      "type": "datasheet",
      "url": "https://www.rockwestcomposites.com/on/demandware.static/Sites-RWC-Site/Sites-rwc-master-catalog/-/wysiwyg/AS4.pdf",
      "year": 2010
    },
    {
      "title": "Hexcel Corporation Form 10-K for fiscal year 2024 (SEC filing)",
      "type": "report",
      "url": "https://www.sec.gov/Archives/edgar/data/717605/000095017025014412/hxl-20241231.htm",
      "year": 2025
    },
    {
      "title": "Environmental and Strain Rate Effects on Graphite/Epoxy Composites (NASA CR-187229)",
      "type": "report",
      "url": "https://ntrs.nasa.gov/api/citations/19920011242/downloads/19920011242.pdf",
      "year": 1991
    },
    {
      "title": "A Comparison of Graphite/Epoxy Tape Laminates and 2-D Braided Composites, Mechanical Properties (NASA CR-4610)",
      "type": "report",
      "url": "https://ntrs.nasa.gov/api/citations/19940033071/downloads/19940033071.pdf",
      "year": 1994
    },
    {
      "title": "Comparison of Requirements for Composite Structures for Aircraft and Space Applications (NASA/TM-2010-216869)",
      "type": "report",
      "url": "https://ntrs.nasa.gov/api/citations/20110003478/downloads/20110003478.pdf",
      "year": 2010
    }
  ],
  "gaps": [
    "No composite density, resin density or laminate CTE for AS4/3501-6 was found in the sources read for this profile. Only the fibre density and CTE were found.",
    "No 3501-6 resin datasheet from Hexcel was found. A reseller page (Knowde) gave Tg figures and an amine-cure description in a search result, but the page could not be read in this run, so none of those values are used here.",
    "No cure schedule for the 3501-6 resin alone was found. The only cure cycle is the NASA nose-cap cocure (4 hr at 375 °F, 85 psig), which is for a sandwich.",
    "No UV, atomic oxygen, outgassing, vacuum or low Earth orbit test result for AS4/3501-6 was found in the sources read. The NASA report has no space-environment data.",
    "No flight data beyond the Space Shuttle SRB nose cap development was found in the sources read. The report describes development and ground testing, not flight results.",
    "No safety data sheet for AS4 or 3501-6 was read. The Hexcel SDS result found in search covers a sized HexTow family that is not AS4-specific, so it was not used.",
    "No CAS number, UNS, EN or other designation for AS4/3501-6 or the 3501-6 resin was printed in the sources read.",
    "Compressive strength, in-plane shear strength, interlaminar shear strength and compressive modulus are not in the property canon. They are stored under snake_case names (compressive_strength, in_plane_shear_strength, interlaminar_shear_strength, compressive_modulus) and need a canon entry or a mapping at import.",
    "The fill compressive strength and modulus at 75 °F and 240 °F in Table 6 are not used, because the scan text was ambiguous and the numbers were not clearly readable in the rendered page.",
    "The Tg-versus-moisture curve is shown only in report figures, which were not read as numbers. NASA CR-187229 reports equilibrium moisture content for unidirectional specimens, but says its absorption curves had not reached equilibrium, so those values are used with that caveat. No Tg value at moisture equilibrium was found. Transverse values from CR-187229 are for unidirectional tape, so they are kept apart from the fabric values.",
    "The Rockwest AS4 sheet also prints HexPly 8552 composite values (0-degree tensile 320 ksi, etc.). These are for a different resin, so they are not used for AS4/3501-6.",
    "Eight sources are cited. The Hexcel AS4D datasheet was fetched but not used, because the AS4D is a 12K fibre with different strength values. A NASA textile-composite ageing paper was fetched but not used, because it covers AS4/E905L rather than AS4/3501-6. A NASA LDEF surface study was read but not used, because it does not name AS4/3501-6.",
    "No producer share by country and no critical-mineral listing was found for PAN-based carbon fibre or the 3501-6 resin. The Hexcel FY2024 10-K names Hexcel as the carbon fibre maker and acrylonitrile as the PAN raw material, without shares.",
    "The NASA outgassing database itself was not queried for this grade. Only its user guide was read, so the TML and CVCM outgassing values for AS4/3501-6 are unquantified.",
    "No uses beyond the SRB composite nose cap and general AS4 fibre processing were found for 3501-6 in the sources read.",
    "Hazard and handling data beyond the Hexcel sentence telling users to read the SDS were not found in the sources read for this profile.",
    "The Wikipedia article is used only for the composition sentence (carbon fibre reinforcement in a polymer matrix, usually epoxy). It gives no numeric value, and its history lines are not used."
  ],
  "story": {
    "why": "Hexcel AS4/3501-6 is a graphite/epoxy composite with a long record in US space hardware. It is the material NASA Marshall chose for the facesheets of the Space Shuttle solid rocket booster composite nose cap, a sandwich with a syntactic foam core. The nose cap was developed to replace a metallic nose cap coated with thermal protection. The report calls the composite's strength-to-weight advantage and the removal of a debris hazard the reasons for the change. The properties below are the lamina values NASA printed for the 8H fabric and the fibre values from the Hexcel datasheet.",
    "uses": [
      {
        "where": "Space Shuttle SRB composite nose cap",
        "line": "NASA and USBI built a composite nose cap for the Space Shuttle solid rocket booster, a sandwich of two AS4/3501-6 facesheets around a SC350G syntactic foam core. The report says the composite sandwich structure removes the thermal protection system that the metallic nose cap needed."
      },
      {
        "where": "Composite parts made from AS4 fibre",
        "line": "Hexcel suggests HexTow AS4 for weaving, prepregging, filament winding, braiding and pultrusion. This describes the fibre product, not the 3501-6 resin specifically."
      }
    ],
    "can_do": [
      {
        "label": "Warp tensile strength",
        "line": "At 75 °F the average warp tensile strength of the 8H AS4/3501-6 lamina was 111.6 ksi, and the A-basis value was 98.0 ksi, per NASA Table 6.",
        "benchmark": "ultimate_tensile_strength",
        "scope": "material",
        "value": "111.6 ksi"
      },
      {
        "label": "Warp tensile strength at 350 °F",
        "line": "After samples were heated to 600 °F and cooled to 350 °F, the average warp tensile strength was 93.9 ksi, per NASA Table 6.",
        "benchmark": "ultimate_tensile_strength",
        "scope": "material",
        "value": "93.9 ksi"
      },
      {
        "label": "Glass transition",
        "line": "The unconditioned laminate had a glass transition temperature of 386 °F by DMA and 380 °F by DSC. A dry sample measured 398 °F by DMA, per NASA Section 2.3.",
        "benchmark": "glass_transition_temperature",
        "scope": "material",
        "value": "386 °F"
      },
      {
        "label": "Fibre strength",
        "line": "The AS4 carbon fibre tow has a typical tensile strength of 4,433 MPa (643 ksi), per the Hexcel AS4 datasheet. This is a fibre value, not a laminate value.",
        "benchmark": "ultimate_tensile_strength",
        "scope": "material",
        "value": "4433 MPa"
      }
    ],
    "compare": "NASA CR-4610 (1994) compares AS4/3501-6 unidirectional tape laminates with 2-D braided composites. It reports that the braided material had a severe unnotched transverse strength reduction compared with the tape laminates, and that the braids showed no notch sensitivity at the single hole size tested. The NASA nose cap report compares the composite with the metallic nose cap it replaced only in terms of strength-to-weight and debris. The lamina values above are the basis for the compare table, which uses the same measurement names as the other profiles.",
    "compare_rows": [
      {
        "label": "Warp tensile strength",
        "benchmark": "ultimate_tensile_strength",
        "scope": "material"
      },
      {
        "label": "Glass transition",
        "benchmark": "glass_transition_temperature",
        "scope": "material"
      },
      {
        "label": "Warp tensile modulus",
        "benchmark": "elastic_modulus",
        "scope": "material"
      }
    ],
    "handling": [
      "Read the supplier safety data sheet before handling. No hazard classification for AS4/3501-6 was found in the sources read.",
      "Keep moisture out of the laminate. Moisture lowers the glass transition temperature, mostly in the first 10 days at 180 °F and 93% RH.",
      "For wet test coupons, use the NASA conditioning of 10 days at 180 °F and 93% RH."
    ],
    "good_for": [
      "Flight-heritage structural laminates. NASA used it for the facesheets of the Space Shuttle solid rocket booster composite nose cap.",
      "Strength at moderate temperature. The warp tensile strength is 111.6 ksi at 75 °F and 93.9 ksi at 350 °F after a 600 °F excursion, per NASA Table 6."
    ],
    "watch_out": [
      "Moisture. The glass transition temperature falls with moisture uptake, mostly in the first 10 days at 180 °F and 93% RH.",
      "High temperature. Warp tensile strength falls to 74.8 ksi at 550 °F and to 74.6 ksi at 480 °F (warp, average), per NASA Table 6.",
      "Fibre misalignment in fabrication. The NASA report saw up to 6 degrees of fill misalignment in lot 2 prepreg.",
      "Notches and transverse loads. NASA CR-4610 reports that tape laminates show some notch sensitivity. NASA CR-187229 Table 5.1 shows transverse tensile strength falling with 1% moisture."
    ],
    "verdict": "AS4/3501-6 is a well-documented ground-test laminate with NASA lamina data at temperatures from 75 °F to 550 °F. The sources read here do not cover space-environment exposure or resin-level data, so those gaps should be closed before it is used beyond the nose-cap heritage.",
    "recipe": {
      "line": "AS4/3501-6 is a graphite/epoxy composite. Its reinforcement is Hexcel AS4, a PAN-based carbon fibre woven as 8-harness satin fabric from 3K tows, and its matrix is a 3501-6 epoxy resin. In the NASA nose cap the laminate was cocured in an autoclave for 4 hr at 375 °F and 85 psig, with a ramp of 2 to 3 °F per minute and cooling of 1 to 2 °F per minute.",
      "parts": [
        {
          "name": "Carbon fibre (AS4, PAN-based)",
          "symbol": "C",
          "role": "Carries the load. The fibre sets the tensile strength and stiffness of the laminate in the fibre direction."
        },
        {
          "name": "3501-6 epoxy resin",
          "role": "Holds the fibres together, transfers load between them and sets the glass transition temperature (about 380 to 398 °F in the NASA tests)."
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "No safety data sheet for AS4/3501-6 was read, so this profile does not give a hazard classification. The Hexcel AS4 datasheet tells users to read the safety data sheet before use.",
        "points": [
          {
            "label": "Before use",
            "line": "Read the supplier safety data sheet for the exact prepreg or fibre before handling. The NASA report does not list hazard data for the resin."
          }
        ],
        "level": 0,
        "verdict": "No hazard classification found in the sources read"
      },
      {
        "title": "If the laminate overheats or stays wet",
        "lead": "These effects come from the NASA material tests, not from incidents.",
        "points": [
          {
            "label": "Moisture",
            "line": "At 180 °F and 93% relative humidity the glass transition temperature falls, mostly in the first 10 days. The dry value is 398 °F by DMA and the unconditioned value is 386 °F by DMA."
          },
          {
            "label": "Above the glass transition",
            "line": "The NASA report says a moisture-conditioned laminate would change with exposure time at 600 °F, which is well above the glass transition temperature."
          }
        ]
      },
      {
        "title": "Handling and storage",
        "points": [
          {
            "label": "Coupon conditioning",
            "line": "NASA conditioned all wet test coupons at 180 °F and 93% relative humidity for 10 days, and found this sufficient for the moisture absorption of the composite."
          },
          {
            "label": "Fabrication",
            "line": "In the NASA lot 2 prepreg, fibre misalignment as high as 6 degrees on as many as half the plies gave large scatter in high-temperature fill tensile results."
          }
        ]
      }
    ]
  },
  "updated": "2026-11-01",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 35,
    "unreachable": 0,
    "caveats": 3,
    "note": "Written by an AI assistant on 2026-11-01 from the NASA TM 2000-210252 report (Table 6 read from the rendered page) and the Rockwest copy of the Hexcel AS4 datasheet. Eight sources cited, including NASA CR-187229 (unidirectional transverse and moisture values), NASA CR-4610 (notch sensitivity), NASA/TM-2010-216869 (delamination), the Hexcel FY2024 10-K (supply) and the NASA outgassing user guide (test method only). The Hexcel AS4D datasheet was fetched but not used for values."
  },
  "sources": {
    "nasa-tm-2000-210252": {
      "title": "Mechanical Property Allowables Generated for the Solid Rocket Booster Composite Nose Cap (NASA/TM-2000-210252)",
      "id": "NASA/TM-2000-210252 (A.J. Hodge, Marshall Space Flight Center, May 2000)",
      "url": "https://ntrs.nasa.gov/api/citations/20000060843/downloads/20000060843.pdf",
      "year": 2000,
      "kind": "report",
      "license": "public domain (NASA)"
    },
    "hexcel-as4-datasheet": {
      "title": "HexTow AS4 Carbon Fiber Product Data Sheet (Hexcel Corporation, March 2010), copy hosted by Rockwest Composites",
      "id": "Hexcel HexTow AS4 Product Data, March 2010",
      "url": "https://www.rockwestcomposites.com/on/demandware.static/Sites-RWC-Site/Sites-rwc-master-catalog/-/wysiwyg/AS4.pdf",
      "year": 2010,
      "kind": "datasheet",
      "license": "supplier document, linked not reproduced"
    },
    "hexcel-10k-fy2024": {
      "title": "Hexcel Corporation Form 10-K for fiscal year 2024 (SEC filing)",
      "id": "SEC EDGAR filing for CIK 717605, accession 0000950170-25-014412",
      "url": "https://www.sec.gov/Archives/edgar/data/717605/000095017025014412/hxl-20241231.htm",
      "year": 2025,
      "kind": "report",
      "license": "public SEC filing"
    },
    "nasa-cr-187229": {
      "title": "Environmental and Strain Rate Effects on Graphite/Epoxy Composites (NASA CR-187229)",
      "id": "NASA CR-187229, Konstantinos Peimandis, Northwestern University, October 1991 (NTRS 19920011242)",
      "url": "https://ntrs.nasa.gov/api/citations/19920011242/downloads/19920011242.pdf",
      "year": 1991,
      "kind": "report",
      "license": "public domain (NASA)"
    },
    "nasa-cr-4610": {
      "title": "A Comparison of Graphite/Epoxy Tape Laminates and 2-D Braided Composites, Mechanical Properties (NASA CR-4610)",
      "id": "NASA CR-4610, Pierre J. Minguet and Christian K. Gunther, Boeing Defense and Space Group, July 1994 (NTRS 19940033071)",
      "url": "https://ntrs.nasa.gov/api/citations/19940033071/downloads/19940033071.pdf",
      "year": 1994,
      "kind": "report",
      "license": "public domain (NASA)"
    },
    "nasa-tm-2010-216869": {
      "title": "Comparison of Requirements for Composite Structures for Aircraft and Space Applications (NASA/TM-2010-216869)",
      "id": "NASA/TM-2010-216869, Ivatury S. Raju and co-authors, NASA Langley Research Center, December 2010 (NTRS 20110003478)",
      "url": "https://ntrs.nasa.gov/api/citations/20110003478/downloads/20110003478.pdf",
      "year": 2010,
      "kind": "report",
      "license": "public domain (NASA)"
    },
    "nasa-outgassing-guide": {
      "title": "NASA Outgassing Database User Guide (NASA Goddard Space Flight Center)",
      "id": "NASA GSFC outgassing database user guide",
      "url": "https://etd.gsfc.nasa.gov/capabilities/outgassing-database/user-guide/",
      "kind": "web",
      "license": "public domain (NASA)"
    },
    "wikipedia-cfrp": {
      "title": "Carbon fiber reinforced polymer (Wikipedia)",
      "id": "Wikipedia article Carbon_fiber-reinforced_polymer",
      "url": "https://en.wikipedia.org/wiki/Carbon_fiber-reinforced_polymer",
      "kind": "web",
      "license": "CC BY-SA 4.0 (linked, not reproduced)"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/as4-3501-6/"
}