{
  "spore": "profile",
  "id": "titanium-grade-23",
  "spore_version": "0.2",
  "family": "titanium-alloys",
  "name": "Titanium alloy Ti-6Al-4V ELI (Grade 23)",
  "abbreviation": "Ti-6Al-4V ELI",
  "role": "structural alloy",
  "category": "metals",
  "type": "titanium",
  "summary": "Ti-6Al-4V ELI (Grade 23) is the extra-low-interstitial version of Ti-6Al-4V. It has tighter limits on iron, oxygen, carbon, nitrogen and hydrogen, and the sources read here tie those limits to higher fracture toughness and better behaviour at cryogenic temperatures. UPMET gives a density of 4.42 g/cm3 at 22 degC and, for annealed bar to ASTM B348 at 20 degC, a 0.2 % yield strength of 759 MPa with a tensile strength of 828 MPa and 10 % elongation.\n",
  "best_for": "Cold-service hardware and medical implants where toughness and low interstitial content matter (Carpenter; UPMET; Titanium Industries).",
  "weakest_at": "Thermal conduction: 6.6 W/(m K) at 20 degC is low for a metal (UPMET). The sources read give no room-temperature fracture toughness for commercial bar.",
  "identity": {
    "formula": "Ti-6Al-4V ELI (Grade 23): titanium with 5.5 to 6.5 wt % aluminium and 3.5 to 4.5 wt % vanadium, with tighter limits on oxygen, iron, carbon, nitrogen and hydrogen; nominal composition, no fixed chemical formula",
    "designations": [
      {
        "system": "UNS",
        "code": "R56407",
        "note": "ASTM B265 and B348 Grade 23",
        "source": "ti-grade23",
        "where": "Table 1 heading: ASTM B265/B348 Grade 23 is UNS R56407"
      },
      {
        "system": "UNS",
        "code": "R56401",
        "note": "ASTM F136 surgical implant alloy",
        "source": "ti-grade23",
        "where": "Table 1 heading: ASTM F136 is UNS R56401"
      },
      {
        "system": "ASTM",
        "code": "B348",
        "note": "Grade 23, the high-purity alloy",
        "source": "carpenter-eli",
        "where": "Product description: also known as ASTM B348 Grade 23"
      },
      {
        "system": "ASTM",
        "code": "F136",
        "note": "wrought alloy for surgical implants",
        "source": "carpenter-eli",
        "where": "Applicable Specifications list"
      },
      {
        "system": "ASTM",
        "code": "B265",
        "note": "sheet and plate, Grade 23",
        "source": "ti-grade23",
        "where": "Plate and sheet specification lines (ASTM B265 Gr 23)"
      },
      {
        "system": "ASTM",
        "code": "F620",
        "note": "forgings for surgical implants",
        "source": "carpenter-eli",
        "where": "Applicable Specifications list"
      },
      {
        "system": "AMS",
        "code": "4907",
        "note": "sheet, strip and plate, annealed",
        "source": "sae-ams4907c",
        "where": "Title: AMS4907C, titanium alloy sheet, strip and plate 6Al-4V, extra low interstitial annealed"
      },
      {
        "system": "AMS",
        "code": "4930",
        "note": "bar and plate",
        "source": "upmet-ti64eli",
        "where": "Datasheet title: AMS 4930, 6932"
      },
      {
        "system": "AMS",
        "code": "6932",
        "note": "bar and plate",
        "source": "upmet-ti64eli",
        "where": "Datasheet title: AMS 4930, 6932"
      },
      {
        "system": "AMS",
        "code": "4931",
        "note": "bar, wire, forgings and billet",
        "source": "carpenter-eli",
        "where": "Applicable Specifications list"
      }
    ],
    "source": "ti-grade23",
    "where": "Table 1, chemical composition: Grade 23 column (UNS R56407) and ASTM F136 column (UNS R56401)"
  },
  "tags": {
    "environments": [],
    "stresses": [
      "extreme-cold"
    ],
    "applications": [
      "structures",
      "propulsion-and-tanks"
    ]
  },
  "properties": [
    {
      "benchmark": "density",
      "label": "Density",
      "value": 4.42,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "condition": "not stated for physical properties",
        "temperature": "22 degC (72 degF as printed)"
      },
      "method": "Value printed in the Physical Properties table of the UPMET datasheet, SI column",
      "status": "ground",
      "source": "upmet-ti64eli",
      "where": "Physical Properties table, Density row, 22 degC, 4.42 g cm-3",
      "source_detail": {
        "title": "Ti-6Al-4V ELI titanium bar and plate datasheet (AMS 4930, 6932; UNS R56401, R56407)",
        "id": "United Performance Metals (UPMET)",
        "url": "https://www.upmet.com/sites/default/files/datasheets/ti-6al-4v-eli.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "supplier datasheet, cited not reproduced"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting (liquidus) point",
      "value": 1650,
      "value_high": 1660,
      "bound": "range",
      "unit": "degC",
      "scope": "material",
      "conditions": {
        "basis": "liquidus, as printed",
        "condition": "not stated"
      },
      "method": "Printed range in the Physical Properties table of the UPMET datasheet",
      "status": "ground",
      "uncertainty": "plus or minus 14 degC, as printed",
      "source": "upmet-ti64eli",
      "where": "Physical Properties table, Melting (liquidus) point row, 1650-1660 degC",
      "source_detail": {
        "title": "Ti-6Al-4V ELI titanium bar and plate datasheet (AMS 4930, 6932; UNS R56401, R56407)",
        "id": "United Performance Metals (UPMET)",
        "url": "https://www.upmet.com/sites/default/files/datasheets/ti-6al-4v-eli.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "supplier datasheet, cited not reproduced"
      }
    },
    {
      "benchmark": "beta_transus",
      "label": "Beta-transus temperature",
      "value": 966,
      "bound": "exact",
      "unit": "degC",
      "scope": "material",
      "conditions": {
        "basis": "beta transus, as printed",
        "condition": "not stated"
      },
      "method": "Value printed in the Physical Properties table of the UPMET datasheet",
      "status": "ground",
      "uncertainty": "plus or minus 14 degC, as printed",
      "source": "upmet-ti64eli",
      "where": "Physical Properties table, Beta Transus row, 966 degC",
      "source_detail": {
        "title": "Ti-6Al-4V ELI titanium bar and plate datasheet (AMS 4930, 6932; UNS R56401, R56407)",
        "id": "United Performance Metals (UPMET)",
        "url": "https://www.upmet.com/sites/default/files/datasheets/ti-6al-4v-eli.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "supplier datasheet, cited not reproduced"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "label": "Thermal conductivity",
      "value": 6.6,
      "bound": "exact",
      "unit": "W/(m K)",
      "scope": "material",
      "conditions": {
        "temperature": "20 degC (68 degF as printed)",
        "condition": "not stated"
      },
      "method": "Value printed in the Physical Properties table of the UPMET datasheet, SI column",
      "status": "ground",
      "source": "upmet-ti64eli",
      "where": "Physical Properties table, Thermal Conductivity row, 20 degC, 6.6 W m-1 K-1",
      "source_detail": {
        "title": "Ti-6Al-4V ELI titanium bar and plate datasheet (AMS 4930, 6932; UNS R56401, R56407)",
        "id": "United Performance Metals (UPMET)",
        "url": "https://www.upmet.com/sites/default/files/datasheets/ti-6al-4v-eli.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "supplier datasheet, cited not reproduced"
      }
    },
    {
      "benchmark": "specific_heat",
      "label": "Specific heat capacity",
      "value": 0.58,
      "bound": "exact",
      "unit": "J/(g K)",
      "scope": "material",
      "conditions": {
        "temperature": "20 degC (68 degF as printed)",
        "condition": "not stated"
      },
      "method": "Value printed in the Physical Properties table of the UPMET datasheet, SI column",
      "status": "ground",
      "source": "upmet-ti64eli",
      "where": "Physical Properties table, Specific Heat row, 20 degC, 0.580 J g-1 K-1",
      "source_detail": {
        "title": "Ti-6Al-4V ELI titanium bar and plate datasheet (AMS 4930, 6932; UNS R56401, R56407)",
        "id": "United Performance Metals (UPMET)",
        "url": "https://www.upmet.com/sites/default/files/datasheets/ti-6al-4v-eli.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "supplier datasheet, cited not reproduced"
      }
    },
    {
      "benchmark": "cte",
      "label": "Mean coefficient of thermal expansion",
      "value": 9,
      "bound": "exact",
      "unit": "10^-6 /degC",
      "scope": "material",
      "conditions": {
        "temperature_range": "0 to 100 degC (32 to 212 degF as printed)",
        "basis": "mean coefficient, metric column"
      },
      "method": "Value printed in the Physical Properties table of the UPMET datasheet",
      "status": "ground",
      "source": "upmet-ti64eli",
      "where": "Physical Properties table, Mean Coefficient of Thermal Expansion row, 20-100 degC metric column, 9.0x10-6 m m-1 degC-1",
      "source_detail": {
        "title": "Ti-6Al-4V ELI titanium bar and plate datasheet (AMS 4930, 6932; UNS R56401, R56407)",
        "id": "United Performance Metals (UPMET)",
        "url": "https://www.upmet.com/sites/default/files/datasheets/ti-6al-4v-eli.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "supplier datasheet, cited not reproduced"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Young's modulus at 20 degC",
      "value": 107,
      "value_high": 122,
      "bound": "range",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "temperature": "20 degC (68 degF as printed)",
        "basis": "range as printed (15.5 to 17.7 Msi)"
      },
      "method": "Printed range in the Physical Properties table of the UPMET datasheet",
      "status": "ground",
      "source": "upmet-ti64eli",
      "where": "Physical Properties table, Young's Modulus row, 68 degF (20 degC), 107-122 GPa",
      "source_detail": {
        "title": "Ti-6Al-4V ELI titanium bar and plate datasheet (AMS 4930, 6932; UNS R56401, R56407)",
        "id": "United Performance Metals (UPMET)",
        "url": "https://www.upmet.com/sites/default/files/datasheets/ti-6al-4v-eli.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "supplier datasheet, cited not reproduced"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Young's modulus at 230 degC",
      "value": 95,
      "value_high": 111,
      "bound": "range",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "temperature": "230 degC (450 degF as printed)",
        "basis": "range as printed (13.8 to 16.2 Msi)"
      },
      "method": "Printed range in the Physical Properties table of the UPMET datasheet",
      "status": "ground",
      "source": "upmet-ti64eli",
      "where": "Physical Properties table, Young's Modulus row, 450 degF (230 degC), 95-111 GPa",
      "source_detail": {
        "title": "Ti-6Al-4V ELI titanium bar and plate datasheet (AMS 4930, 6932; UNS R56401, R56407)",
        "id": "United Performance Metals (UPMET)",
        "url": "https://www.upmet.com/sites/default/files/datasheets/ti-6al-4v-eli.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "supplier datasheet, cited not reproduced"
      }
    },
    {
      "benchmark": "shear_modulus",
      "label": "Shear modulus",
      "value": 41,
      "value_high": 45,
      "bound": "range",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "temperature": "20 degC (68 degF as printed)",
        "basis": "range as printed (5.9 to 6.5 Msi)"
      },
      "method": "Printed range in the Physical Properties table of the UPMET datasheet",
      "status": "ground",
      "source": "upmet-ti64eli",
      "where": "Physical Properties table, Shear Modulus row, 68 degF (20 degC), 41-45 GPa",
      "source_detail": {
        "title": "Ti-6Al-4V ELI titanium bar and plate datasheet (AMS 4930, 6932; UNS R56401, R56407)",
        "id": "United Performance Metals (UPMET)",
        "url": "https://www.upmet.com/sites/default/files/datasheets/ti-6al-4v-eli.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "supplier datasheet, cited not reproduced"
      }
    },
    {
      "benchmark": "electrical_resistivity",
      "label": "Electrical resistivity",
      "value": 1.68,
      "bound": "exact",
      "unit": "μΩ·m",
      "scope": "material",
      "conditions": {
        "temperature": "0 degC (32 degF as printed)",
        "condition": "not stated"
      },
      "method": "Value printed in the Physical Properties table of the UPMET datasheet",
      "status": "ground",
      "source": "upmet-ti64eli",
      "where": "Physical Properties table, Electrical Resistivity row, 32 degF (0 degC), 1.68 μΩ·m",
      "source_detail": {
        "title": "Ti-6Al-4V ELI titanium bar and plate datasheet (AMS 4930, 6932; UNS R56401, R56407)",
        "id": "United Performance Metals (UPMET)",
        "url": "https://www.upmet.com/sites/default/files/datasheets/ti-6al-4v-eli.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "supplier datasheet, cited not reproduced"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Ultimate tensile strength, annealed bar to ASTM B348",
      "value": 828,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "condition": "annealed",
        "product_form": "bar, up to 3.00 in round or thickness",
        "specification": "ASTM B348",
        "direction": "L",
        "temperature": "20 degC (68 degF as printed)",
        "printed_as": "120 ksi (828 MPa)"
      },
      "method": "Printed in the mechanical properties table of the UPMET datasheet, annealed row, L direction",
      "status": "ground",
      "source": "upmet-ti64eli",
      "where": "Mechanical Properties table, ASTM B348 row (up to 3.00 in), UTS column, 120 ksi (828 MPa)",
      "source_detail": {
        "title": "Ti-6Al-4V ELI titanium bar and plate datasheet (AMS 4930, 6932; UNS R56401, R56407)",
        "id": "United Performance Metals (UPMET)",
        "url": "https://www.upmet.com/sites/default/files/datasheets/ti-6al-4v-eli.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "supplier datasheet, cited not reproduced"
      }
    },
    {
      "benchmark": "yield_strength",
      "label": "0.2 % yield strength, annealed bar to ASTM B348",
      "value": 759,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "condition": "annealed",
        "product_form": "bar, up to 3.00 in round or thickness",
        "specification": "ASTM B348",
        "direction": "L",
        "temperature": "20 degC (68 degF as printed)",
        "offset": "printed as .02 % YS (read as the usual 0.2 % offset)",
        "printed_as": "110 ksi (759 MPa)"
      },
      "method": "Printed in the mechanical properties table of the UPMET datasheet, annealed row, L direction",
      "status": "ground",
      "note": "The datasheet header prints '.02% YS'; it is read as the usual 0.2 % offset. Check the mill certificate.",
      "source": "upmet-ti64eli",
      "where": "Mechanical Properties table, ASTM B348 row, 0.02% YS column, 110 ksi (759 MPa)",
      "source_detail": {
        "title": "Ti-6Al-4V ELI titanium bar and plate datasheet (AMS 4930, 6932; UNS R56401, R56407)",
        "id": "United Performance Metals (UPMET)",
        "url": "https://www.upmet.com/sites/default/files/datasheets/ti-6al-4v-eli.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "supplier datasheet, cited not reproduced"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation, annealed bar to ASTM B348",
      "value": 10,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "condition": "annealed",
        "product_form": "bar, up to 3.00 in round or thickness",
        "specification": "ASTM B348",
        "direction": "L",
        "temperature": "20 degC (68 degF as printed)"
      },
      "method": "Printed in the mechanical properties table of the UPMET datasheet, annealed row, L direction",
      "status": "ground",
      "source": "upmet-ti64eli",
      "where": "Mechanical Properties table, ASTM B348 row, Elongation column, 10%",
      "source_detail": {
        "title": "Ti-6Al-4V ELI titanium bar and plate datasheet (AMS 4930, 6932; UNS R56401, R56407)",
        "id": "United Performance Metals (UPMET)",
        "url": "https://www.upmet.com/sites/default/files/datasheets/ti-6al-4v-eli.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "supplier datasheet, cited not reproduced"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength range, annealed sheet, strip and plate to AMS 4907",
      "value": 125,
      "value_high": 130,
      "bound": "range",
      "unit": "ksi",
      "scope": "material",
      "conditions": {
        "condition": "annealed",
        "product_form": "sheet, strip and plate",
        "specification": "AMS 4907",
        "temperature": "not stated on the page",
        "range_note": "varies with orientation, section thickness and engineering requirements"
      },
      "method": "Printed range in Table 2 of the Titanium Industries AMS 4907 page, which describes itself as a reference summary and not the specification",
      "status": "ground",
      "source": "ti-ams4907",
      "where": "AMS 4907 Specification, Table 2, Tensile Strength 125 - 130 ksi",
      "source_detail": {
        "title": "AMS 4907: titanium grade 23 sheet, strip and plate, annealed (Titanium Industries specification page)",
        "id": "Titanium Industries",
        "url": "https://titanium.com/ams-4907-specification/",
        "year": 2026,
        "kind": "datasheet",
        "license": "supplier web page, cited not reproduced"
      }
    },
    {
      "benchmark": "yield_strength",
      "label": "Yield strength range, annealed sheet, strip and plate to AMS 4907",
      "value": 115,
      "value_high": 120,
      "bound": "range",
      "unit": "ksi",
      "scope": "material",
      "conditions": {
        "condition": "annealed",
        "product_form": "sheet, strip and plate",
        "specification": "AMS 4907",
        "temperature": "not stated on the page",
        "offset": "not stated on the page"
      },
      "method": "Printed range in Table 2 of the Titanium Industries AMS 4907 page, which describes itself as a reference summary and not the specification",
      "status": "ground",
      "source": "ti-ams4907",
      "where": "AMS 4907 Specification, Table 2, Yield Strength 115 - 120 ksi",
      "source_detail": {
        "title": "AMS 4907: titanium grade 23 sheet, strip and plate, annealed (Titanium Industries specification page)",
        "id": "Titanium Industries",
        "url": "https://titanium.com/ams-4907-specification/",
        "year": 2026,
        "kind": "datasheet",
        "license": "supplier web page, cited not reproduced"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation range, annealed sheet, strip and plate to AMS 4907",
      "value": 6,
      "value_high": 10,
      "bound": "range",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "condition": "annealed",
        "product_form": "sheet, strip and plate",
        "specification": "AMS 4907",
        "temperature": "not stated on the page"
      },
      "method": "Printed range in Table 2 of the Titanium Industries AMS 4907 page, which describes itself as a reference summary and not the specification",
      "status": "ground",
      "source": "ti-ams4907",
      "where": "AMS 4907 Specification, Table 2, Elongation 6 - 10%",
      "source_detail": {
        "title": "AMS 4907: titanium grade 23 sheet, strip and plate, annealed (Titanium Industries specification page)",
        "id": "Titanium Industries",
        "url": "https://titanium.com/ams-4907-specification/",
        "year": 2026,
        "kind": "datasheet",
        "license": "supplier web page, cited not reproduced"
      }
    },
    {
      "benchmark": "fracture_toughness",
      "label": "Fracture toughness K_Ic(J) at 293 K, research ELI forging",
      "value": 57.5,
      "bound": "exact",
      "unit": "MPa√m",
      "scope": "material",
      "conditions": {
        "alloy": "ELI research alloy, nominal oxygen 0.10 mass %",
        "processing": "forged (paper's Table 2)",
        "heat_treatment": "7.2 ks at 973 K, air-cooled",
        "test": "compact tension, J-integral K_Ic(J)",
        "temperature": "293 K"
      },
      "method": "Measured in the 1991 ISIJ study; value read from the ELI forged row of Table 3",
      "status": "ground",
      "source": "isij-1991",
      "where": "Table 3, ELI, Forged, 293 K row, K_Ic(J) column",
      "source_detail": {
        "title": "Cryogenic Mechanical Properties of Ti-6Al-4V Alloys with Three Levels of Oxygen Content",
        "id": "ISIJ International Vol. 31 (1991), No. 8, pp. 882-889",
        "url": "https://ynu.repo.nii.ac.jp/record/3983/files/A-11%20ISIJ31.pdf",
        "year": 1991,
        "kind": "paper",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "fracture_toughness",
      "label": "Fracture toughness K_Ic(J) at 77 K, research ELI forging",
      "value": 42.9,
      "bound": "exact",
      "unit": "MPa√m",
      "scope": "material",
      "conditions": {
        "alloy": "ELI research alloy, nominal oxygen 0.10 mass %",
        "processing": "forged (paper's Table 2)",
        "heat_treatment": "7.2 ks at 973 K, air-cooled",
        "test": "compact tension, J-integral K_Ic(J)",
        "temperature": "77 K"
      },
      "method": "Measured in the 1991 ISIJ study; value read from the ELI forged row of Table 3",
      "status": "ground",
      "source": "isij-1991",
      "where": "Table 3, ELI, Forged, 77 K row, K_Ic(J) column",
      "source_detail": {
        "title": "Cryogenic Mechanical Properties of Ti-6Al-4V Alloys with Three Levels of Oxygen Content",
        "id": "ISIJ International Vol. 31 (1991), No. 8, pp. 882-889",
        "url": "https://ynu.repo.nii.ac.jp/record/3983/files/A-11%20ISIJ31.pdf",
        "year": 1991,
        "kind": "paper",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "fracture_toughness",
      "label": "Fracture toughness K_Ic(J) at 4 K, research ELI forging",
      "value": 44.9,
      "bound": "exact",
      "unit": "MPa√m",
      "scope": "material",
      "conditions": {
        "alloy": "ELI research alloy, nominal oxygen 0.10 mass %",
        "processing": "forged (paper's Table 2)",
        "heat_treatment": "7.2 ks at 973 K, air-cooled",
        "test": "compact tension, J-integral K_Ic(J)",
        "temperature": "4 K"
      },
      "method": "Measured in the 1991 ISIJ study; value read from the ELI forged row of Table 3",
      "status": "ground",
      "source": "isij-1991",
      "where": "Table 3, ELI, Forged, 4 K row, K_Ic(J) column",
      "source_detail": {
        "title": "Cryogenic Mechanical Properties of Ti-6Al-4V Alloys with Three Levels of Oxygen Content",
        "id": "ISIJ International Vol. 31 (1991), No. 8, pp. 882-889",
        "url": "https://ynu.repo.nii.ac.jp/record/3983/files/A-11%20ISIJ31.pdf",
        "year": 1991,
        "kind": "paper",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "yield_strength",
      "label": "0.2 % yield strength at 293 K, research ELI forging",
      "value": 908,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "alloy": "ELI research alloy, nominal oxygen 0.10 mass %",
        "processing": "forged (paper's Table 2)",
        "heat_treatment": "7.2 ks at 973 K, air-cooled",
        "offset": "yield strength, principally 0.2 % offset (paper's wording)",
        "temperature": "293 K"
      },
      "method": "Measured in the 1991 ISIJ study; value read from the ELI forged row of Table 3",
      "status": "ground",
      "source": "isij-1991",
      "where": "Table 3, ELI, Forged, 293 K row, YS column",
      "source_detail": {
        "title": "Cryogenic Mechanical Properties of Ti-6Al-4V Alloys with Three Levels of Oxygen Content",
        "id": "ISIJ International Vol. 31 (1991), No. 8, pp. 882-889",
        "url": "https://ynu.repo.nii.ac.jp/record/3983/files/A-11%20ISIJ31.pdf",
        "year": 1991,
        "kind": "paper",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength at 293 K, research ELI forging",
      "value": 953,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "alloy": "ELI research alloy, nominal oxygen 0.10 mass %",
        "processing": "forged (paper's Table 2)",
        "heat_treatment": "7.2 ks at 973 K, air-cooled",
        "temperature": "293 K"
      },
      "method": "Measured in the 1991 ISIJ study; value read from the ELI forged row of Table 3",
      "status": "ground",
      "source": "isij-1991",
      "where": "Table 3, ELI, Forged, 293 K row, TS column",
      "source_detail": {
        "title": "Cryogenic Mechanical Properties of Ti-6Al-4V Alloys with Three Levels of Oxygen Content",
        "id": "ISIJ International Vol. 31 (1991), No. 8, pp. 882-889",
        "url": "https://ynu.repo.nii.ac.jp/record/3983/files/A-11%20ISIJ31.pdf",
        "year": 1991,
        "kind": "paper",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength at 77 K, research ELI forging",
      "value": 1502,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "alloy": "ELI research alloy, nominal oxygen 0.10 mass %",
        "processing": "forged (paper's Table 2)",
        "heat_treatment": "7.2 ks at 973 K, air-cooled",
        "temperature": "77 K"
      },
      "method": "Measured in the 1991 ISIJ study; value read from the ELI forged row of Table 3",
      "status": "ground",
      "source": "isij-1991",
      "where": "Table 3, ELI, Forged, 77 K row, TS column",
      "source_detail": {
        "title": "Cryogenic Mechanical Properties of Ti-6Al-4V Alloys with Three Levels of Oxygen Content",
        "id": "ISIJ International Vol. 31 (1991), No. 8, pp. 882-889",
        "url": "https://ynu.repo.nii.ac.jp/record/3983/files/A-11%20ISIJ31.pdf",
        "year": 1991,
        "kind": "paper",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "reduction_of_area",
      "label": "Reduction of area at 293 K, research ELI forging",
      "value": 41.5,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "alloy": "ELI research alloy, nominal oxygen 0.10 mass %",
        "processing": "forged (paper's Table 2)",
        "heat_treatment": "7.2 ks at 973 K, air-cooled",
        "temperature": "293 K"
      },
      "method": "Measured in the 1991 ISIJ study; value read from the ELI forged row of Table 3",
      "status": "ground",
      "source": "isij-1991",
      "where": "Table 3, ELI, Forged, 293 K row, RA column",
      "source_detail": {
        "title": "Cryogenic Mechanical Properties of Ti-6Al-4V Alloys with Three Levels of Oxygen Content",
        "id": "ISIJ International Vol. 31 (1991), No. 8, pp. 882-889",
        "url": "https://ynu.repo.nii.ac.jp/record/3983/files/A-11%20ISIJ31.pdf",
        "year": 1991,
        "kind": "paper",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "reduction_of_area",
      "label": "Reduction of area at 77 K, research ELI forging",
      "value": 22,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "alloy": "ELI research alloy, nominal oxygen 0.10 mass %",
        "processing": "forged (paper's Table 2)",
        "heat_treatment": "7.2 ks at 973 K, air-cooled",
        "temperature": "77 K"
      },
      "method": "Measured in the 1991 ISIJ study; value read from the ELI forged row of Table 3",
      "status": "ground",
      "source": "isij-1991",
      "where": "Table 3, ELI, Forged, 77 K row, RA column",
      "source_detail": {
        "title": "Cryogenic Mechanical Properties of Ti-6Al-4V Alloys with Three Levels of Oxygen Content",
        "id": "ISIJ International Vol. 31 (1991), No. 8, pp. 882-889",
        "url": "https://ynu.repo.nii.ac.jp/record/3983/files/A-11%20ISIJ31.pdf",
        "year": 1991,
        "kind": "paper",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "reduction_of_area",
      "label": "Reduction of area at 4 K, research ELI forging",
      "value": 27.2,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "alloy": "ELI research alloy, nominal oxygen 0.10 mass %",
        "processing": "forged (paper's Table 2)",
        "heat_treatment": "7.2 ks at 973 K, air-cooled",
        "temperature": "4 K"
      },
      "method": "Measured in the 1991 ISIJ study; value read from the ELI forged row of Table 3",
      "status": "ground",
      "source": "isij-1991",
      "where": "Table 3, ELI, Forged, 4 K row, RA column",
      "source_detail": {
        "title": "Cryogenic Mechanical Properties of Ti-6Al-4V Alloys with Three Levels of Oxygen Content",
        "id": "ISIJ International Vol. 31 (1991), No. 8, pp. 882-889",
        "url": "https://ynu.repo.nii.ac.jp/record/3983/files/A-11%20ISIJ31.pdf",
        "year": 1991,
        "kind": "paper",
        "license": "cited, not reproduced"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Marine and salt water (listed application)",
      "headline": "The supplier describes good corrosion resistance and lists marine and salt water uses.",
      "effect": "Titanium Industries says the grade is used where toughness, high strength, light weight and good corrosion resistance are needed, and lists marine and salt water applications. This is a supplier statement with no test conditions on the page.",
      "rating": "low",
      "conditions": {
        "basis": "supplier statement; no test conditions printed"
      },
      "source": "ti-grade23",
      "where": "Introduction paragraph and Typical uses list"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "PubChem's Primary Hazards entry for titanium (CID 23963) reads 'Not Classified' in the JSON record read in this run. The record covers titanium metal in general, not this alloy or its powder.",
        "ghs": [],
        "source": "pubchem-ti",
        "where": "Primary Hazards section, JSON view of CID 23963"
      }
    ],
    "failure_risks": [
      {
        "mode": "Lower fracture toughness at cryogenic temperature",
        "trigger": "Service at 77 K or 4 K (research ELI forging with nominal oxygen 0.10 mass %)",
        "consequence": "K_Ic(J) fell from 57.5 MPa√m at 293 K to 42.9 at 77 K and 44.9 at 4 K in the research forging. Design toughness at the service temperature, not at room temperature.",
        "severity": "moderate",
        "source": "isij-1991",
        "where": "Table 3, ELI forged rows, K_Ic(J) column"
      },
      {
        "mode": "Property scatter with orientation and section thickness",
        "trigger": "Orientation and section thickness",
        "consequence": "Tensile properties vary with orientation and section thickness, so the minimum for the product form governs the design.",
        "severity": "low",
        "source": "ti-ams4907",
        "where": "AMS 4907 page, Table 2 note"
      }
    ],
    "side_effects": [],
    "handling": [
      {
        "text": "Hydrogen maximum is 0.0125 % for ASTM B265 and B348 Grade 23 and 0.012 % for ASTM F136. Name the specification on the order.",
        "source": "ti-grade23",
        "where": "Table 1, chemical composition, H row"
      },
      {
        "text": "Tensile requirements vary with orientation, section thickness and engineering requirements; check the requirement for the product form before design.",
        "source": "ti-ams4907",
        "where": "AMS 4907 page, Table 2 note"
      }
    ],
    "mitigations": []
  },
  "uses": [
    {
      "application": "structures",
      "device": "Air frames and aircraft structural parts",
      "example": "UPMET lists air frames as an industry application of Ti-6Al-4V ELI bar and plate, and Titanium Industries lists aircraft applications for Grade 23.",
      "source": "upmet-ti64eli",
      "where": "Industry Applications list (UPMET); Typical uses paragraph (Titanium Industries)"
    },
    {
      "application": "propulsion-and-tanks",
      "device": "Jet and engine rocket components; pressure vessels",
      "example": "UPMET lists jet and engine rocket components and pressure vessels among its industry applications.",
      "source": "upmet-ti64eli",
      "where": "Industry Applications list"
    },
    {
      "application": "propulsion-and-tanks",
      "device": "Cryogenic and high-pressure vessels",
      "example": "Titanium Industries lists cryogenic and high pressure vessels among the typical uses of Grade 23.",
      "source": "ti-grade23",
      "where": "Typical uses paragraph"
    }
  ],
  "supply": [
    {
      "subject": "Titanium (sponge, the feedstock for mill products)",
      "abundance": "Not stated in the USGS titanium chapter, which gives tonnages only.",
      "producers": [
        {
          "country": "China",
          "share_percent": 70.3,
          "year": 2025
        },
        {
          "country": "Japan",
          "share_percent": 14.3,
          "year": 2025
        },
        {
          "country": "Russia",
          "share_percent": 6.8,
          "year": 2025
        },
        {
          "country": "Kazakhstan",
          "share_percent": 4.3,
          "year": 2025
        },
        {
          "country": "Saudi Arabia",
          "share_percent": 3.2,
          "year": 2025
        }
      ],
      "critical_lists": [
        {
          "list": "USGS 2025 Final List of Critical Minerals (MCS 2026, Table 6)",
          "listed": true
        },
        {
          "list": "EU critical raw materials list (titanium metal)",
          "listed": true
        }
      ],
      "recycling": "USGS: owing to limited survey responses, consumption data for titanium scrap in the titanium metal industry were withheld; data for other industries were not available.",
      "substitutes": [
        "USGS: few materials match titanium's strength-to-weight ratio and corrosion resistance; aluminum, nickel, specialty steels and zirconium alloys may be substituted where corrosion resistance is needed."
      ],
      "source": "usgs-ti-2026",
      "where": "World Sponge Metal Production table, 2025e (world total 370,000 t; shares computed by the assistant); Domestic Production and Use; Salient Statistics; Import Sources; Substitutes"
    },
    {
      "subject": "Aluminium (aluminum)",
      "abundance": "USGS aluminum chapter: global bauxite resources are estimated at 55 billion to 75 billion t, sufficient for world demand well into the future.",
      "producers": [
        {
          "country": "China",
          "share_percent": 60.8,
          "year": 2025
        },
        {
          "country": "India",
          "share_percent": 5.7,
          "year": 2025
        },
        {
          "country": "Russia",
          "share_percent": 5.3,
          "year": 2025
        },
        {
          "country": "Canada",
          "share_percent": 4.5,
          "year": 2025
        },
        {
          "country": "United Arab Emirates",
          "share_percent": 3.6,
          "year": 2025
        }
      ],
      "critical_lists": [
        {
          "list": "USGS 2025 Final List of Critical Minerals (MCS 2026, Table 6)",
          "listed": true
        },
        {
          "list": "EU critical raw materials list (bauxite and aluminium, merged)",
          "listed": true
        }
      ],
      "recycling": "USGS: about 3.6 million tons of aluminum were recovered from purchased scrap in the United States; old-scrap recovery equalled about 28 % of apparent consumption.",
      "substitutes": [
        "USGS: composites can replace aluminum in aircraft fuselages and wings; composites, magnesium, steel and titanium can replace it in ground transportation."
      ],
      "source": "usgs-al-2026",
      "where": "World Smelter Production table, 2025e (thousand metric tons; world total 74,000; shares computed by the assistant); Domestic Production and Use; Salient Statistics; Recycling; Substitutes"
    },
    {
      "subject": "Vanadium",
      "abundance": "USGS vanadium chapter: world resources exceed 63 million t; world reserves are 21,000 t (2025e).",
      "producers": [
        {
          "country": "China",
          "share_percent": 74.5,
          "year": 2025
        },
        {
          "country": "Russia",
          "share_percent": 19.1,
          "year": 2025
        },
        {
          "country": "Brazil",
          "share_percent": 4.8,
          "year": 2025
        },
        {
          "country": "South Africa",
          "share_percent": 4.5,
          "year": 2025
        }
      ],
      "critical_lists": [
        {
          "list": "USGS 2025 Final List of Critical Minerals (MCS 2026, Table 6)",
          "listed": true
        },
        {
          "list": "EU critical raw materials list (vanadium)",
          "listed": true
        }
      ],
      "recycling": "USGS: vanadium recycling is mainly the reprocessing of vanadium catalysts into new catalysts.",
      "substitutes": [
        "USGS: other alloying elements can replace vanadium in steel; platinum and nickel can replace vanadium compounds as catalysts; no acceptable substitute is available for aerospace titanium alloys."
      ],
      "source": "usgs-v-2026",
      "where": "World Mine Production and Reserves table, 2025e (thousand metric tons; world total 110,000; shares computed by the assistant); Domestic Production and Use; Import Sources; Substitutes"
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "UPMET datasheet: Ti-6Al-4V ELI titanium bar and plate (AMS 4930, 6932)",
      "type": "datasheet",
      "url": "https://www.upmet.com/sites/default/files/datasheets/ti-6al-4v-eli.pdf",
      "year": 2026
    },
    {
      "title": "Titanium Industries: Ti 6Al-4V ELI (Grade 23) bar, plate and sheet",
      "type": "datasheet",
      "url": "https://titanium.com/alloys/titanium-and-titanium-alloys/ti-grade-6al-4v-eli-grade-23/",
      "year": 2026
    },
    {
      "title": "Titanium Industries: AMS 4907 sheet, strip and plate, annealed (specification page)",
      "type": "datasheet",
      "url": "https://titanium.com/ams-4907-specification/",
      "year": 2026
    },
    {
      "title": "Carpenter Technology: Ti 6Al-4V ELI alloy page (UNS R56407)",
      "type": "datasheet",
      "url": "https://www.carpentertechnology.com/alloy-finder/Ti-6Al-4V-Eli",
      "year": 2026
    },
    {
      "title": "SAE International: AMS4907C titanium alloy sheet, strip and plate 6Al-4V, extra low interstitial annealed",
      "type": "standard",
      "url": "https://saemobilus.sae.org/standards/ams4907c-titanium-alloy-sheet-strip-plate-6al-4v-extra-low-interstital-annealed",
      "year": 2026
    },
    {
      "title": "Cryogenic Mechanical Properties of Ti-6Al-4V Alloys with Three Levels of Oxygen Content (ISIJ International 31, 1991)",
      "type": "paper",
      "url": "https://ynu.repo.nii.ac.jp/record/3983/files/A-11%20ISIJ31.pdf",
      "year": 1991
    },
    {
      "title": "USGS Mineral Commodity Summaries 2026: Titanium",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-titanium.pdf",
      "year": 2026
    },
    {
      "title": "USGS Mineral Commodity Summaries 2026: Vanadium",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-vanadium.pdf",
      "year": 2026
    },
    {
      "title": "USGS Mineral Commodity Summaries 2026: Aluminum",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-aluminum.pdf",
      "year": 2026
    },
    {
      "title": "USGS Mineral Commodity Summaries 2026, full volume (Table 6, U.S. Final 2025 Critical Minerals List)",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026.pdf",
      "year": 2026
    },
    {
      "title": "European Commission: critical raw materials list",
      "type": "report",
      "url": "https://single-market-economy.ec.europa.eu/sectors/raw-materials/areas-specific-interest/critical-raw-materials_en",
      "year": 2024
    },
    {
      "title": "PubChem: Titanium (CID 23963), JSON record",
      "type": "database",
      "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23963/JSON",
      "year": 2026
    }
  ],
  "gaps": [
    "Room-temperature fracture toughness (K_IC) for commercial ELI bar or plate: no fetched source. The only fracture-toughness values are from the 1991 research forging (K_Ic(J), nominal oxygen 0.10 mass %), which is not a certificate.",
    "Research forging, yield strength at 77 K, yield and tensile strength at 4 K, and all elongation values: the table image was read, but the PDF text layer is garbled, so the gate cannot match them and they are not entered.",
    "Commercial-grade cryogenic tensile and toughness data for ELI bar (for example from NIST or NASA): no fetched source.",
    "Oxygen: UPMET prints 0.013 % as the maximum. This is very probably a typo for 0.13 %, the value Titanium Industries and Carpenter both print. The UPMET value is not used.",
    "Nitrogen: the maximum is 0.030 % in Titanium Industries and UPMET, but 0.050 % in Carpenter. Both are printed in the composition note; the mill certificate governs.",
    "Hydrogen: 0.0125 % maximum for ASTM B265 and B348 and 0.012 % for ASTM F136 (Titanium Industries); Carpenter prints 0.013 %.",
    "Poisson's ratio: UPMET prints .31 at 20 degC without a leading zero, which the source-text check cannot match, so it is not entered.",
    "Property names not in spores/property-canon.yaml: beta_transus, fracture_toughness and reduction_of_area. Short snake_case names are used for them.",
    "Powder and swarf hazard: an H228 flammable-solid statement for titanium seen in an earlier run is not printed in the PubChem record read in this run, so it is not used. No alloy-specific hazard data were read.",
    "Galling, fretting and hydrogen embrittlement of ELI: no fetched source.",
    "Corrosion in seawater, acids, chlorides or body fluid for ELI: no test data in a fetched source. The only corrosion entry is a supplier statement.",
    "Space and orbital data for ELI (outgassing, atomic-oxygen erosion, thermal cycling): no fetched source.",
    "EN, DIN, JIS, GB and ISO codes: none printed for this grade by a fetched source, so none are listed. Medical implant use is described in the story only, because the application list has no medical slot.",
    "Heat-treatment windows and process route (melting, forging, rolling) for commercial ELI bar: no fetched source. The research forging was heat-treated at 973 K for 7.2 ks and air-cooled."
  ],
  "story": {
    "why": "Ti-6Al-4V ELI (Grade 23) is the extra-low-interstitial form of the alloy. Its limits on iron, oxygen, carbon, nitrogen and hydrogen are tighter than standard Ti-6Al-4V, and the sources read here tie that to better fracture toughness and cryogenic behaviour. Carpenter says it has been the material of choice for many medical and dental applications because of its biocompatibility, fatigue strength and low modulus.",
    "uses": [
      {
        "where": "Aircraft and jet hardware",
        "line": "UPMET lists air frames, jet and engine rocket components and pressure vessels. Titanium Industries lists aircraft applications."
      },
      {
        "where": "Cryogenic and high-pressure vessels",
        "line": "Titanium Industries lists cryogenic and high pressure vessels as typical uses. Carpenter says the ELI grade has better mechanical properties at cryogenic temperatures than standard Ti-6Al-4V."
      },
      {
        "where": "Medical and dental implants",
        "line": "UPMET and Titanium Industries list implants, dental, spinal and orthopaedic hardware. Carpenter cites ASTM F136 (wrought alloy for surgical implants) for this use."
      }
    ],
    "can_do": [
      {
        "label": "Toughness at cold temperatures",
        "line": "In a 1991 research study of forged ELI material with nominal oxygen 0.10 mass %, fracture toughness K_Ic(J) was 57.5 MPa√m at 293 K, 42.9 at 77 K and 44.9 at 4 K. These are research values, not certificate minima.",
        "benchmark": "fracture_toughness",
        "scope": "material",
        "value": "57.5 MPa√m at 293 K; 42.9 at 77 K; 44.9 at 4 K"
      },
      {
        "label": "Strength of annealed bar",
        "line": "Annealed bar to ASTM B348 has a 0.2 % yield strength of 759 MPa and a tensile strength of 828 MPa at 20 degC, with 10 % elongation (UPMET).",
        "benchmark": "yield_strength",
        "scope": "material"
      },
      {
        "label": "Stiffness",
        "line": "Young's modulus is 107 to 122 GPa at 20 degC and 95 to 111 GPa at 230 degC (UPMET).",
        "benchmark": "elastic_modulus",
        "scope": "material"
      },
      {
        "label": "Density",
        "line": "Density is 4.42 g/cm3 at 22 degC (UPMET).",
        "benchmark": "density",
        "scope": "material"
      }
    ],
    "compare": "ELI keeps the main alloy elements of Ti-6Al-4V but sets lower limits on iron, oxygen, carbon, nitrogen and hydrogen (Carpenter; UPMET; Titanium Industries). Titanium Industries says Grade 23 is produced at a higher purity than Grade 5. The sources read here give this grade's own values only, so the compare rows use this grade's data and no side-by-side Grade 5 strength figures are claimed.",
    "compare_rows": [
      {
        "label": "Density",
        "benchmark": "density",
        "scope": "material"
      },
      {
        "label": "Elastic modulus",
        "benchmark": "elastic_modulus",
        "scope": "material"
      },
      {
        "label": "Yield strength",
        "benchmark": "yield_strength",
        "scope": "material"
      }
    ],
    "handling": [
      "Specify the product form and specification on the order. AMS 4907 covers annealed sheet, strip and plate; ASTM B265 and B348 Grade 23 cover sheet, plate and bar (Titanium Industries).",
      "Tensile values vary with orientation and section thickness, so check the minimum for the product form that the buyer's specification names (Titanium Industries, AMS 4907 page).",
      "Powder and swarf: PubChem does not classify titanium as hazardous in the record read here, and no alloy-specific fire data were read. Check a supplier safety data sheet for fine particles."
    ],
    "good_for": [
      "Cold-service structures that need toughness: the 1991 research forging kept K_Ic(J) at 42.9 MPa√m at 77 K and 44.9 at 4 K.",
      "Implants and dental hardware: Carpenter cites excellent biocompatibility, good fatigue strength and low modulus.",
      "Strength for its weight: annealed bar gives a 0.2 % yield strength of 759 MPa at 20 degC for a density of 4.42 g/cm3 (UPMET)."
    ],
    "watch_out": [
      "Oxygen: UPMET prints 0.013 % as the maximum, very probably a typo for 0.13 %, which Titanium Industries and Carpenter both print (0.130). Only 0.13 % is used here.",
      "Nitrogen: the maximum is 0.030 % in Titanium Industries and UPMET but 0.050 % in Carpenter. Check the mill certificate.",
      "Cryogenic values come from one research forging with 0.10 % oxygen, not from a certificate for commercial bar.",
      "Thermal conductivity is low: 6.6 W/(m K) at 20 degC (UPMET)."
    ],
    "verdict": "Ti-6Al-4V ELI is the low-interstitial version of Ti-6Al-4V for medical implants and cold-service structures. The sources here support its tighter limits, its better damage tolerance and its cryogenic behaviour. The numbers come from supplier datasheets and one 1991 research paper; take certified minima from the governing specification.",
    "recipe": {
      "line": "Ti-6Al-4V ELI is titanium with 5.5 to 6.5 wt % aluminium and 3.5 to 4.5 wt % vanadium, and maximum limits on iron, oxygen, carbon, nitrogen and hydrogen that are tighter than standard Ti-6Al-4V. The limits are from the Titanium Industries Table 1 (ASTM B265 and B348 Grade 23 column). The process route is not described in the sources read here.",
      "parts": [
        {
          "name": "Titanium",
          "symbol": "Ti",
          "role": "Base metal. Most of the alloy is titanium, which gives low density and corrosion resistance.",
          "share_note": "balance (the rest)",
          "source": "ti-grade23",
          "where": "Table 1; balance implied by the other limits"
        },
        {
          "name": "Aluminium",
          "symbol": "Al",
          "role": "Alpha stabiliser.",
          "share_percent": 5.5,
          "share_high": 6.5,
          "source": "ti-grade23",
          "where": "Table 1, Al 5.5 to 6.5 %"
        },
        {
          "name": "Vanadium",
          "symbol": "V",
          "role": "Beta stabiliser.",
          "share_percent": 3.5,
          "share_high": 4.5,
          "source": "ti-grade23",
          "where": "Table 1, V 3.5 to 4.5 %"
        },
        {
          "name": "Iron",
          "symbol": "Fe",
          "role": "Impurity with a maximum limit. The ELI limit is lower than the standard Ti-6Al-4V limit (see compare).",
          "share_high": 0.25,
          "share_note": "maximum 0.25 %",
          "source": "ti-grade23",
          "where": "Table 1, Fe maximum 0.25 %"
        },
        {
          "name": "Oxygen",
          "symbol": "O",
          "role": "Interstitial with a maximum limit. The 1991 study found the lowest-oxygen alloy had the best ductility at 4 K.",
          "share_high": 0.13,
          "share_note": "maximum 0.13 %",
          "source": "ti-grade23",
          "where": "Table 1, O maximum 0.13 %; Carpenter prints O maximum 0.130"
        },
        {
          "name": "Carbon",
          "symbol": "C",
          "role": "Interstitial with a maximum limit.",
          "share_high": 0.08,
          "share_note": "maximum 0.080 %",
          "source": "ti-grade23",
          "where": "Table 1, C maximum 0.080 %"
        },
        {
          "name": "Nitrogen",
          "symbol": "N",
          "role": "Interstitial with a maximum limit. Two suppliers print different limits.",
          "share_high": 0.03,
          "share_note": "maximum 0.030 % (Carpenter prints 0.050 %)",
          "source": "ti-grade23",
          "where": "Table 1, N maximum 0.030 %"
        },
        {
          "name": "Hydrogen",
          "symbol": "H",
          "role": "Interstitial with a maximum limit.",
          "share_high": 0.0125,
          "share_note": "maximum 0.0125 % (B265 and B348); 0.012 % for F136",
          "source": "ti-grade23",
          "where": "Table 1, H maximum 0.0125 % (B265/B348) and 0.012 % (F136)"
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "The alloy is not classified as hazardous in the PubChem record read in this run. No supplier safety data sheet for this alloy was read.",
        "points": [
          {
            "label": "Solid alloy",
            "line": "PubChem's Primary Hazards entry for titanium (CID 23963) reads 'Not Classified'. The record is for titanium metal in general, not for this alloy."
          },
          {
            "label": "Powder and swarf",
            "line": "No hazard statement for powder or swarf was printed in the record read here, so the fire hazard of fine particles is not assessed (see gaps)."
          }
        ],
        "level": 0,
        "verdict": "Not classified in PubChem"
      },
      {
        "title": "Cold service",
        "lead": "Toughness is lower at 77 K and 4 K than at room temperature in the 1991 research forging.",
        "points": [
          {
            "label": "Room temperature",
            "line": "Fracture toughness K_Ic(J) is 57.5 MPa√m at 293 K in the research ELI forging, which has nominal oxygen 0.10 mass %."
          },
          {
            "label": "77 K and 4 K",
            "line": "K_Ic(J) is 42.9 MPa√m at 77 K and 44.9 MPa√m at 4 K, with reduction of area 22 % and 27.2 %."
          }
        ]
      },
      {
        "title": "Handling and storage",
        "points": [
          {
            "label": "Specification",
            "line": "Order by the specification that names the product form: AMS 4907 for annealed sheet, strip and plate; ASTM B265 and B348 Grade 23 for sheet, plate and bar."
          },
          {
            "label": "Hydrogen",
            "line": "The hydrogen maximum is 0.0125 % for ASTM B265 and B348 Grade 23 and 0.012 % for ASTM F136 (Titanium Industries)."
          }
        ]
      }
    ]
  },
  "updated": "2026-10-24",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 25,
    "unreachable": 0,
    "caveats": 4,
    "note": "Written 2026-10-24 by an assistant from pages fetched in this run: 25 values, 12 sources. Caveats: the 1991 research forging (nominal oxygen 0.10 mass %) is not a certificate; UPMET prints oxygen as 0.013; nitrogen limits conflict between suppliers; AMS 4907 values are a supplier summary of the specification."
  },
  "sources": {
    "upmet-ti64eli": {
      "title": "Ti-6Al-4V ELI titanium bar and plate datasheet (AMS 4930, 6932; UNS R56401, R56407)",
      "id": "United Performance Metals (UPMET)",
      "url": "https://www.upmet.com/sites/default/files/datasheets/ti-6al-4v-eli.pdf",
      "year": 2026,
      "kind": "datasheet",
      "license": "supplier datasheet, cited not reproduced"
    },
    "ti-grade23": {
      "title": "Ti 6Al-4V ELI (Grade 23) bar, plate and sheet: composition, mechanical properties and specifications",
      "id": "Titanium Industries",
      "url": "https://titanium.com/alloys/titanium-and-titanium-alloys/ti-grade-6al-4v-eli-grade-23/",
      "year": 2026,
      "kind": "datasheet",
      "license": "supplier web page, cited not reproduced"
    },
    "ti-ams4907": {
      "title": "AMS 4907: titanium grade 23 sheet, strip and plate, annealed (Titanium Industries specification page)",
      "id": "Titanium Industries",
      "url": "https://titanium.com/ams-4907-specification/",
      "year": 2026,
      "kind": "datasheet",
      "license": "supplier web page, cited not reproduced"
    },
    "carpenter-eli": {
      "title": "Ti 6Al-4V ELI alloy description and applicable specifications (Carpenter Technology)",
      "id": "Carpenter Technology",
      "url": "https://www.carpentertechnology.com/alloy-finder/Ti-6Al-4V-Eli",
      "year": 2026,
      "kind": "datasheet",
      "license": "supplier web page, cited not reproduced"
    },
    "sae-ams4907c": {
      "title": "AMS4907C: titanium alloy sheet, strip, and plate 6Al-4V, extra low interstitial annealed (material specification record)",
      "id": "SAE International, doi 10.4271/AMS4907C",
      "url": "https://saemobilus.sae.org/standards/ams4907c-titanium-alloy-sheet-strip-plate-6al-4v-extra-low-interstital-annealed",
      "year": 2026,
      "kind": "standard",
      "license": "SAE record, cited not reproduced"
    },
    "isij-1991": {
      "title": "Cryogenic Mechanical Properties of Ti-6Al-4V Alloys with Three Levels of Oxygen Content",
      "id": "ISIJ International Vol. 31 (1991), No. 8, pp. 882-889",
      "url": "https://ynu.repo.nii.ac.jp/record/3983/files/A-11%20ISIJ31.pdf",
      "year": 1991,
      "kind": "paper",
      "license": "cited, not reproduced"
    },
    "usgs-ti-2026": {
      "title": "Mineral Commodity Summaries 2026: Titanium (USGS)",
      "id": "USGS MCS 2026, Titanium",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-titanium.pdf",
      "year": 2026,
      "kind": "report",
      "license": "US Government work, public domain"
    },
    "usgs-v-2026": {
      "title": "Mineral Commodity Summaries 2026: Vanadium (USGS)",
      "id": "USGS MCS 2026, Vanadium",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-vanadium.pdf",
      "year": 2026,
      "kind": "report",
      "license": "US Government work, public domain"
    },
    "usgs-al-2026": {
      "title": "Mineral Commodity Summaries 2026: Aluminum (USGS)",
      "id": "USGS MCS 2026, Aluminum",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-aluminum.pdf",
      "year": 2026,
      "kind": "report",
      "license": "US Government work, public domain"
    },
    "usgs-mcs-2026": {
      "title": "Mineral Commodity Summaries 2026, full volume: Table 6, The U.S. Final 2025 Critical Minerals List",
      "id": "USGS MCS 2026 (full volume)",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026.pdf",
      "year": 2026,
      "kind": "report",
      "license": "US Government work, public domain"
    },
    "ec-crm": {
      "title": "Critical raw materials (European Commission, list under Regulation (EU) 2024/1252)",
      "id": "European Commission",
      "url": "https://single-market-economy.ec.europa.eu/sectors/raw-materials/areas-specific-interest/critical-raw-materials_en",
      "year": 2024,
      "kind": "web",
      "license": "European Commission web page"
    },
    "pubchem-ti": {
      "title": "PubChem: Titanium (CID 23963), primary hazards (JSON record)",
      "id": "PubChem CID 23963",
      "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23963/JSON",
      "year": 2026,
      "kind": "database",
      "license": "public domain (NCBI)"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/titanium-grade-23/"
}