{
  "spore": "profile",
  "id": "aluminium-6061",
  "spore_version": "0.2",
  "family": "aluminium-alloys",
  "name": "Aluminium alloy 6061",
  "abbreviation": "6061",
  "role": "structural alloy",
  "category": "metals",
  "type": "aluminium",
  "summary": "6061 is a wrought aluminium alloy (one that is rolled, extruded or forged rather than cast) whose main additions are magnesium and silicon. In the T6 temper its typical yield strength is 276 MPa and its density is 2.7 g/cm3. A 1972 NASA handbook says aluminium alloys such as 6061 have been used in launch vehicles and spacecraft with excellent success and are relatively insensitive to the space environment, but that the alloy is attacked by strong alkalis and by hydrochloric and hydrofluoric acids.\n",
  "best_for": "A light, workable structural metal with good corrosion resistance (the NASA handbook ranks 6061 best of the heat-treatable aluminium alloys for corrosion)",
  "weakest_at": "Galvanic attack when coupled to more noble metals, especially in sea water (NASA handbook); typical strength values are marked not for design",
  "identity": {
    "formula": "Al-Mg-Si alloy; composition limits in wt%: Al 95.8 to 98.6 (remainder), Mg 0.8 to 1.2, Si 0.4 to 0.8, Cu 0.15 to 0.4, Cr 0.04 to 0.35, Fe max 0.7, Zn max 0.25, Mn max 0.15, Ti max 0.15",
    "designations": [
      {
        "system": "UNS",
        "code": "A96061",
        "source": "asm-6061",
        "where": "Key Words line, UNS A96061"
      },
      {
        "system": "AA",
        "code": "6061",
        "source": "asm-6061",
        "where": "Key Words line, AA6061-T6 (AA number; the temper is not a designation)"
      },
      {
        "system": "ISO",
        "code": "AlMg1SiCu",
        "source": "asm-6061",
        "where": "Key Words line, ISO AlMg1SiCu"
      },
      {
        "system": "EN",
        "code": "3.3211",
        "source": "alloysintl-6061",
        "where": "Designations and cross reference table, Werkstoff (W.Nr) 3.3211"
      },
      {
        "system": "EN name",
        "code": "AW-6061",
        "source": "alloysintl-6061",
        "where": "Designations and cross reference table, EN designation EN AW-6061"
      },
      {
        "system": "AMS",
        "code": "4021",
        "source": "alloysintl-6061",
        "where": "Commonly ordered specifications list, AMS 4021"
      },
      {
        "system": "AMS",
        "code": "4022",
        "source": "alloysintl-6061",
        "where": "Commonly ordered specifications list, AMS 4022"
      },
      {
        "system": "AMS",
        "code": "4023",
        "source": "alloysintl-6061",
        "where": "Commonly ordered specifications list, AMS 4023"
      },
      {
        "system": "AMS",
        "code": "4026",
        "source": "alloysintl-6061",
        "where": "Commonly ordered specifications list, AMS 4026"
      },
      {
        "system": "AMS",
        "code": "4027",
        "note": "sheet and plate",
        "source": "sae-ams4027",
        "where": "Title line, AMS4027G (6061; -T6 Sheet, -T651 Plate)"
      },
      {
        "system": "AMS",
        "code": "4115",
        "source": "alloysintl-6061",
        "where": "Commonly ordered specifications list, AMS 4115"
      },
      {
        "system": "AMS",
        "code": "4150",
        "note": "extrusions and rings",
        "source": "sae-ams4150",
        "where": "Title line, AMS4150M (6061-T6), extrusions and rings"
      }
    ],
    "source": "asm-6061",
    "where": "Composition table of the ASM Material Data Sheet for 6061-T6 (aluminium content calculated as remainder; composition from the Aluminum Association, marked not for design)"
  },
  "tags": {
    "environments": [
      "launch",
      "low-earth-orbit"
    ],
    "stresses": [
      "micrometeoroids-and-debris",
      "galling-and-cold-welding"
    ],
    "applications": [
      "structures",
      "propulsion-and-tanks"
    ]
  },
  "properties": [
    {
      "benchmark": "yield_strength",
      "label": "Tensile yield strength, typical, T6 and T651",
      "value": 276,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "temper": "T6 and T651 (datasheet covers both)",
        "basis": "Aluminum Association typical value, marked NOT FOR DESIGN",
        "temperature": "room temperature (not stated)",
        "product_form": "not stated"
      },
      "method": "Typical value listed in a datasheet (ASM Material Data Sheet, Aluminum Association data)",
      "status": "ground",
      "source": "asm-6061",
      "where": "Mechanical Properties table, row Tensile Yield Strength",
      "source_detail": {
        "title": "ASM Material Data Sheet: Aluminum 6061-T6; 6061-T651 (printed copy, 12 May 2023)",
        "id": "ASM/MatWeb bassnum ma6061t6; data from Alcoa, Starmet and the Aluminum Association",
        "url": "https://quickparts.com/wp-content/uploads/2024/05/Aluminum-6061.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "MatWeb terms of use (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Ultimate tensile strength, typical, T6 and T651",
      "value": 310,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "temper": "T6 and T651 (datasheet covers both)",
        "basis": "Aluminum Association typical value, marked NOT FOR DESIGN",
        "temperature": "room temperature (not stated)",
        "product_form": "not stated"
      },
      "method": "Typical value listed in a datasheet (ASM Material Data Sheet, Aluminum Association data)",
      "status": "ground",
      "source": "asm-6061",
      "where": "Mechanical Properties table, row Ultimate Tensile Strength",
      "source_detail": {
        "title": "ASM Material Data Sheet: Aluminum 6061-T6; 6061-T651 (printed copy, 12 May 2023)",
        "id": "ASM/MatWeb bassnum ma6061t6; data from Alcoa, Starmet and the Aluminum Association",
        "url": "https://quickparts.com/wp-content/uploads/2024/05/Aluminum-6061.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "MatWeb terms of use (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation at break (round bar specimen)",
      "value": 17,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "temper": "T6 and T651",
        "specimen": "1/2 in. (12.7 mm) diameter",
        "basis": "Aluminum Association typical value",
        "note": "the same table lists 12 % for a 1/16 in. (1.6 mm) thick specimen, so elongation depends on specimen size"
      },
      "method": "Typical value listed in a datasheet",
      "status": "ground",
      "source": "asm-6061",
      "where": "Mechanical Properties table, row Elongation at Break (second entry)",
      "source_detail": {
        "title": "ASM Material Data Sheet: Aluminum 6061-T6; 6061-T651 (printed copy, 12 May 2023)",
        "id": "ASM/MatWeb bassnum ma6061t6; data from Alcoa, Starmet and the Aluminum Association",
        "url": "https://quickparts.com/wp-content/uploads/2024/05/Aluminum-6061.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "MatWeb terms of use (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Modulus of elasticity",
      "value": 68.9,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "temper": "T6 and T651",
        "basis": "average of tension and compression; compression modulus is about 2 % greater than tensile (datasheet comment)",
        "type": "Aluminum Association typical value"
      },
      "method": "Typical value listed in a datasheet",
      "status": "ground",
      "source": "asm-6061",
      "where": "Mechanical Properties table, row Modulus of Elasticity",
      "source_detail": {
        "title": "ASM Material Data Sheet: Aluminum 6061-T6; 6061-T651 (printed copy, 12 May 2023)",
        "id": "ASM/MatWeb bassnum ma6061t6; data from Alcoa, Starmet and the Aluminum Association",
        "url": "https://quickparts.com/wp-content/uploads/2024/05/Aluminum-6061.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "MatWeb terms of use (cited, not reproduced)"
      }
    },
    {
      "benchmark": "fatigue_strength",
      "label": "Fatigue strength at 500,000,000 cycles",
      "value": 96.5,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "temper": "T6 and T651",
        "loading": "completely reversed stress",
        "test": "RR Moore machine and specimen",
        "cycles": "500,000,000",
        "basis": "Aluminum Association typical value"
      },
      "method": "Typical value listed in a datasheet",
      "status": "ground",
      "source": "asm-6061",
      "where": "Mechanical Properties table, row Fatigue Strength",
      "source_detail": {
        "title": "ASM Material Data Sheet: Aluminum 6061-T6; 6061-T651 (printed copy, 12 May 2023)",
        "id": "ASM/MatWeb bassnum ma6061t6; data from Alcoa, Starmet and the Aluminum Association",
        "url": "https://quickparts.com/wp-content/uploads/2024/05/Aluminum-6061.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "MatWeb terms of use (cited, not reproduced)"
      }
    },
    {
      "benchmark": "density",
      "value": 2.7,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "basis": "Aluminum Association typical value",
        "temper": "T6 and T651",
        "temperature": "room temperature (not stated)"
      },
      "method": "Typical value listed in a datasheet",
      "status": "ground",
      "source": "asm-6061",
      "where": "Physical Properties table, row Density",
      "source_detail": {
        "title": "ASM Material Data Sheet: Aluminum 6061-T6; 6061-T651 (printed copy, 12 May 2023)",
        "id": "ASM/MatWeb bassnum ma6061t6; data from Alcoa, Starmet and the Aluminum Association",
        "url": "https://quickparts.com/wp-content/uploads/2024/05/Aluminum-6061.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "MatWeb terms of use (cited, not reproduced)"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "label": "Thermal conductivity at room temperature",
      "value": 167,
      "bound": "exact",
      "unit": "W/(m·K)",
      "scope": "material",
      "conditions": {
        "temperature": "77 °F",
        "temper": "T6 and T651",
        "basis": "Aluminum Association typical value"
      },
      "method": "Typical value listed in a datasheet",
      "status": "ground",
      "source": "asm-6061",
      "where": "Thermal Properties table, row Thermal Conductivity",
      "source_detail": {
        "title": "ASM Material Data Sheet: Aluminum 6061-T6; 6061-T651 (printed copy, 12 May 2023)",
        "id": "ASM/MatWeb bassnum ma6061t6; data from Alcoa, Starmet and the Aluminum Association",
        "url": "https://quickparts.com/wp-content/uploads/2024/05/Aluminum-6061.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "MatWeb terms of use (cited, not reproduced)"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "label": "Thermal conductivity at 77 K (curve-fit value)",
      "value": 83.5,
      "bound": "exact",
      "unit": "W/(m·K)",
      "scope": "material",
      "conditions": {
        "temperature": "77 K",
        "temper": "T6",
        "fit_range": "data 4 to 300 K, equation 1 to 300 K",
        "fit_error": "0.5 % relative to the underlying data"
      },
      "method": "Calculated by Space Mushroom by evaluating the NIST log10 polynomial fit (coefficients a to i as printed on the NIST page) at 77 K; the page tabulates no values and gives only the equation",
      "status": "calculated",
      "note": "The same fit gives about 154 W/(m·K) at 293 K, close to the room-temperature datasheet value, which supports the transcription of the coefficients.",
      "source": "nist-6061",
      "where": "Thermal Conductivity coefficient block (a = 0.07918, b = 1.0957, c = -0.07277, d = 0.08084, e = 0.02803, f = -0.09464, g = 0.04179, h = -0.00571, i = 0)",
      "source_detail": {
        "title": "Material Properties: 6061-T6 Aluminum (UNS A96061), NIST Cryogenic Material Properties",
        "id": "NIST Cryogenics Technologies Group, curve fits for 4 to 300 K",
        "url": "https://trc.nist.gov/cryogenics/materials/6061%20Aluminum/6061_T6Aluminum_rev.htm",
        "kind": "database",
        "license": "NIST public web page"
      }
    },
    {
      "benchmark": "cte",
      "label": "Mean coefficient of thermal expansion, 68 to 212 °F",
      "value": 23.6,
      "bound": "exact",
      "unit": "ppm/K",
      "scope": "material",
      "conditions": {
        "temperature_range": "68 to 212 °F (20 to 100 °C)",
        "unit_in_source": "µm/m-°C, equal to ppm/K",
        "temper": "T6 and T651",
        "basis": "Aluminum Association typical value",
        "note": "an estimated 25.2 µm/m-°C for 20 to 300 °C is also listed"
      },
      "method": "Typical value listed in a datasheet",
      "status": "ground",
      "source": "asm-6061",
      "where": "Thermal Properties table, row CTE, linear 68°F",
      "source_detail": {
        "title": "ASM Material Data Sheet: Aluminum 6061-T6; 6061-T651 (printed copy, 12 May 2023)",
        "id": "ASM/MatWeb bassnum ma6061t6; data from Alcoa, Starmet and the Aluminum Association",
        "url": "https://quickparts.com/wp-content/uploads/2024/05/Aluminum-6061.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "MatWeb terms of use (cited, not reproduced)"
      }
    },
    {
      "benchmark": "melting_range",
      "label": "Melting range (solidus to liquidus)",
      "value": 582,
      "value_high": 652,
      "bound": "range",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "basis": "typical range for the typical composition of wrought products 1/4 inch thickness or greater",
        "note": "eutectic melting can be eliminated by homogenization (datasheet comment)"
      },
      "method": "Typical range listed in a datasheet (solidus 582 °C, liquidus 652 °C)",
      "status": "ground",
      "source": "asm-6061",
      "where": "Thermal Properties table, rows Melting Point, Solidus and Liquidus",
      "source_detail": {
        "title": "ASM Material Data Sheet: Aluminum 6061-T6; 6061-T651 (printed copy, 12 May 2023)",
        "id": "ASM/MatWeb bassnum ma6061t6; data from Alcoa, Starmet and the Aluminum Association",
        "url": "https://quickparts.com/wp-content/uploads/2024/05/Aluminum-6061.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "MatWeb terms of use (cited, not reproduced)"
      }
    },
    {
      "benchmark": "electrical_resistivity",
      "label": "Electrical resistivity, T6",
      "value": 4,
      "bound": "exact",
      "unit": "µΩ·cm",
      "scope": "material",
      "conditions": {
        "temperature": "20 °C",
        "temper": "T6",
        "unit_in_source": "microhm-cm",
        "other_tempers": "3.7 for O temper and 4.3 for T4 in the same section"
      },
      "method": "Value printed in a NASA materials handbook (cites an earlier reference)",
      "status": "ground",
      "source": "nasa-cr123772",
      "where": "Chapter 9, section 9.31 (p. 75)",
      "source_detail": {
        "title": "Materials Data Handbook: Aluminum Alloy 6061 (2nd edition), NASA CR-123772, Western Applied Research and Development for NASA Marshall Space Flight Center",
        "id": "NTRS 19720022808; NAS8-26644; May 1972",
        "url": "https://ntrs.nasa.gov/citations/19720022808",
        "year": 1972,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "thermal_emittance",
      "label": "Emissivity in air",
      "value": 0.035,
      "value_high": 0.07,
      "bound": "range",
      "unit": "dimensionless",
      "scope": "material",
      "conditions": {
        "temperature": "77 °F (25 °C)",
        "atmosphere": "in air",
        "surface_finish": "not stated",
        "alloy_note": "listed under physical properties of the 6061 handbook"
      },
      "method": "Range printed in a NASA materials handbook (cites an earlier reference); the surface condition is not stated",
      "status": "ground",
      "source": "nasa-cr123772",
      "where": "Chapter 9, section 9.61 (p. 75)",
      "source_detail": {
        "title": "Materials Data Handbook: Aluminum Alloy 6061 (2nd edition), NASA CR-123772, Western Applied Research and Development for NASA Marshall Space Flight Center",
        "id": "NTRS 19720022808; NAS8-26644; May 1972",
        "url": "https://ntrs.nasa.gov/citations/19720022808",
        "year": 1972,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Rural, industrial and marine atmospheres",
      "headline": "NASA ranks 6061 as the best-resisting heat-treatable aluminium alloy in air, whatever the temper.",
      "effect": "The handbook says 6061 has high resistance to rural atmospheres and good resistance to weathering in industrial and marine atmospheres, and that its corrosion resistance is independent of temper. Aluminium resists corrosion because it forms a thin, hard, adherent oxide film (the handbook estimates 20 to 100 x 10^-7 mm thick in air) that protects the metal. The handbook says that under normal conditions in ordinary environments the alloy needs no surface protection.",
      "rating": "low",
      "conditions": {
        "basis": "general statements in a 1972 NASA handbook that cite earlier sources; no exposure times or corrosion rates given for 6061",
        "temper": "independent of temper according to the handbook"
      },
      "source": "nasa-cr123772",
      "where": "Chapter 10, sections 10.1, 10.3 and 10.41 (p. 80 to 81)"
    },
    {
      "environment": "Contact with other metals in a conductive liquid (galvanic coupling), especially sea water",
      "headline": "Aluminium is anodic to most common metals, so it corrodes first when the two touch in salty water.",
      "effect": "The handbook says aluminium is strongly anodic to most other common metals (it gives up electrons more readily, so it is the one that corrodes), and that galvanic coupling with them generally produces severe attack on the aluminium, especially in sea water. Table 10.1 lists the electrode potential of 6061-T6 as -0.83 volt against a 0.1 N calomel reference electrode.",
      "rating": "severe",
      "conditions": {
        "basis": "general statement for aluminium and its alloys; the potential in Table 10.1 was measured in an aqueous solution of 53 g NaCl and 3 g H2O2 per litre at 25 °C",
        "alloy": "6061-T6 potential -0.83 volt; 6061-T4 -0.80 volt; clad 6061 -0.96 volt"
      },
      "source": "nasa-cr123772",
      "where": "Chapter 10, section 10.1 (p. 80); Table 10.1 (p. 82)"
    },
    {
      "environment": "Strong alkalis and acids",
      "headline": "Strong alkalis and hydrochloric or hydrofluoric acid attack 6061.",
      "effect": "The handbook lists aqua regia, hydrochloric acid, hydrofluoric acid, lithium hydroxide, perchloric acid, potassium cyanide, potassium and sodium hydroxide and various mercury compounds as severe environments that attack the alloy. Pitting occurs in waters containing chloride or other halogen ions, particularly at crevices or stagnant areas.",
      "rating": "severe",
      "conditions": {
        "basis": "list of attacking environments in a 1972 NASA handbook; no concentrations, temperatures or rates given",
        "note": "the handbook adds that extensive information on the alloy's resistance to chemicals does not appear to be available"
      },
      "source": "nasa-cr123772",
      "where": "Chapter 10, sections 10.1 and 10.3 (p. 80)"
    },
    {
      "environment": "Rocket propellants (hydrazine, nitrogen tetroxide, liquid oxygen)",
      "headline": "In sealed storage tests 6061-T6 resisted hydrazine fuels and nitrogen tetroxide very well.",
      "effect": "6061-T6 stored with hydrazine and a hydrazine-hydrazine nitrate mixture in sealed capsules for 4 years showed excellent resistance to corrosion, and showed excellent resistance and compatibility with nitrogen tetroxide in similar tests. The handbook cautions that surfaces in contact with hydrazine fuels must be free of organic contamination or traces of catalytic metals or ions. In high-velocity impact tests on 6061-T3 tank walls, no interaction occurred with liquid oxygen.",
      "rating": "low",
      "conditions": {
        "storage": "sealed capsules at 110 °F (44 °C) for 4 years (hydrazine tests)",
        "temper": "6061-T6 in the storage tests; 6061-T3 sheet in the impact tests",
        "basis": "ground tests summarised in a 1972 handbook"
      },
      "source": "nasa-cr123772",
      "where": "Chapter 10, section 10.32 (p. 81)"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "PubChem's aggregated GHS reports for aluminium metal (4,079 company reports) give H261 in 90.8% of reports (in contact with water releases flammable gas), H228 in 60.6% (flammable solid) and H250 in 34.2% (catches fire spontaneously if exposed to air). 8.3% of reports say it does not meet GHS criteria. PubChem does not state the physical form the reports cover, so these are element-level statements, not a classification of the alloy as supplied.",
        "ghs": [
          "H261",
          "H228",
          "H250"
        ],
        "source": "pubchem-al",
        "where": "Safety and Hazards, GHS Classification (CID 5359268)"
      },
      {
        "text": "PubChem's aggregated GHS reports for magnesium metal (2,205 company reports) give H228 in 44.9% of reports (flammable solid), H250 in 36.5% (catches fire spontaneously if exposed to air), and H260 in 36.7% (in contact with water releases flammable gases which may ignite spontaneously). 18.4% of reports say it does not meet GHS criteria. As with aluminium, these are element-level statements and do not classify the alloy.",
        "ghs": [
          "H228",
          "H250",
          "H260"
        ],
        "source": "pubchem-mg",
        "where": "Safety and Hazards, GHS Classification (CID 5462224)"
      }
    ],
    "failure_risks": [
      {
        "mode": "Galvanic corrosion of the aluminium",
        "trigger": "6061 in electrical contact with a more noble metal while wet, especially with chloride (sea water)",
        "consequence": "The handbook says the coupling generally produces severe attack on the aluminium.",
        "severity": "high",
        "source": "nasa-cr123772",
        "where": "Chapter 10, section 10.1 (p. 80)"
      },
      {
        "mode": "Faster fatigue crack growth in moist air",
        "trigger": "Cyclic loading of 6061-T6 in a humid atmosphere",
        "consequence": "Water vapour is described as a principal corrosive agent that causes loss of fatigue properties and speeds up crack propagation, especially at low stress intensities. It does not change the crack initiation period; moist-air cycles before initiation did not change total fatigue life.",
        "severity": "moderate",
        "source": "nasa-cr123772",
        "where": "Chapter 10, sections 10.1 and 10.31 and Figure 10.31 (p. 80, 83)"
      },
      {
        "mode": "Stress-corrosion cracking",
        "trigger": "Sustained surface stress together with a corrosive environment",
        "consequence": "The handbook lists paint topcoats as the most effective protection and says zinc-rich paints are the least effective coating against this cracking; it does not give a susceptibility rating for the alloy.",
        "severity": "moderate",
        "source": "nasa-cr123772",
        "where": "Chapter 11, section 11.81"
      },
      {
        "mode": "Cold welding of bare surfaces in space",
        "trigger": "Space radiation removing surface films in vacuum",
        "consequence": "The handbook says indigenous space radiation tends to accelerate removal of surface films, which might cause loss of lubricity and an increased propensity to cold weld.",
        "severity": "moderate",
        "source": "nasa-cr123772",
        "where": "Chapter 6, p. 32"
      }
    ],
    "side_effects": [
      {
        "text": "Surface erosion of aluminium alloys by corpuscular radiation is probably insignificant, of the order of 254 nanometers per year. Sputtering and micrometeoroids can change surface properties by desorption and erosion, which matters if optical properties, lubrication or certain electrical properties are critical.",
        "affects": "Surface finish, optical and lubrication behaviour in space",
        "source": "nasa-cr123772",
        "where": "Chapter 6, section 6.1 (p. 31 to 32)"
      }
    ],
    "handling": [
      {
        "text": "Keep the alloy away from strong alkalis and from hydrochloric and hydrofluoric acid. In contact with hydrazine fuels, surfaces must be free of organic contamination and catalytic metals.",
        "source": "nasa-cr123772",
        "where": "Chapter 10, sections 10.3 and 10.32 (p. 80 to 81)"
      }
    ],
    "mitigations": [
      {
        "text": "Under normal conditions the handbook says 6061 needs no surface protection. For more severe environments, use clad material (commonly clad with alloy 7072), or a topcoat of epoxy-polyamide or polyurethane paint against stress-corrosion cracking.",
        "source": "nasa-cr123772",
        "where": "Chapter 10, section 10.41 (p. 81); Chapter 11, section 11.81"
      }
    ]
  },
  "uses": [
    {
      "application": "structures",
      "device": "Launch vehicle and spacecraft structures (aluminium alloys, 6061 named as a structural alloy)",
      "example": "The NASA handbook says aluminium alloys have been used in both structural and nonstructural applications in launch vehicles and spacecraft with excellent success.",
      "source": "nasa-cr123772",
      "where": "Chapter 6, section 6.1 (p. 31)"
    },
    {
      "application": "propulsion-and-tanks",
      "device": "Simulated propellant tanks of 6061-T3 sheet (ground impact tests, not flown)",
      "example": "High-velocity impact tests on tank walls 0.020 to 0.125 inch thick found no interaction between the 6061-T3 wall and liquid oxygen or hydrazine.",
      "source": "nasa-cr123772",
      "where": "Chapter 10, section 10.32 (p. 81)"
    },
    {
      "application": "mechanisms",
      "device": "Fittings, couplings, hinge pins, valves and valve parts, and hydraulic and brake pistons",
      "example": "The ASM datasheet lists these among typical applications, with aircraft fittings, camera lens mounts, electrical fittings and connectors, and marine hardware.",
      "source": "asm-6061",
      "where": "Applications paragraph"
    }
  ],
  "supply": [
    {
      "subject": "Aluminium (primary smelter production)",
      "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 List of Critical Minerals (listed as Aluminum)",
          "listed": true
        },
        {
          "list": "EU critical raw materials list of 34 (as shown on the European Commission page, which says aluminium and bauxite have been merged)",
          "listed": true
        }
      ],
      "recycling": "USGS: in 2025 aluminium recovered from purchased scrap in the United States was about 3.6 million tons, of which about 56% came from new scrap and 44% from old scrap; recovery from old scrap equalled about 28% of apparent consumption.",
      "substitutes": [
        "USGS: composites can substitute for aluminium in aircraft fuselages and wings; composites, magnesium, steel and titanium in ground transportation; copper can replace it in electrical and heat-exchange applications."
      ],
      "source": "usgs-mcs2026-aluminum",
      "where": "World Smelter Production table, 2025e (world total 74,000 thousand t; shares calculated by Space Mushroom); Recycling; Substitutes. Lists: USGS and European Commission pages (see sources)."
    },
    {
      "subject": "Bauxite (aluminium ore)",
      "producers": [
        {
          "country": "Guinea",
          "share_percent": 34.1,
          "year": 2025
        },
        {
          "country": "Australia",
          "share_percent": 22,
          "year": 2025
        },
        {
          "country": "China",
          "share_percent": 19.8,
          "year": 2025
        },
        {
          "country": "Brazil",
          "share_percent": 7.5,
          "year": 2025
        },
        {
          "country": "India",
          "share_percent": 5.7,
          "year": 2025
        }
      ],
      "critical_lists": [
        {
          "list": "EU critical raw materials list of 34 (Bauxite listed)",
          "listed": true
        }
      ],
      "recycling": "USGS bauxite and alumina chapter: 'None.'",
      "substitutes": [
        "USGS: bauxite is the only raw material used to produce alumina on a commercial scale in the United States; clay and other materials are technically feasible but not currently economically competitive."
      ],
      "source": "usgs-mcs2026-bauxite",
      "where": "World Alumina Refinery and Bauxite Mine Production table, bauxite 2025e (world total 440,000 thousand t; shares calculated by Space Mushroom); Recycling; Substitutes"
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "ASM Material Data Sheet: Aluminum 6061-T6; 6061-T651 (printed copy hosted by Quickparts, May 2023)",
      "type": "datasheet",
      "url": "https://quickparts.com/wp-content/uploads/2024/05/Aluminum-6061.pdf",
      "year": 2023
    },
    {
      "title": "NASA CR-123772: Materials Data Handbook, Aluminum Alloy 6061, 2nd edition (Muraca and Whittick, 1972)",
      "type": "report",
      "url": "https://ntrs.nasa.gov/citations/19720022808",
      "year": 1972
    },
    {
      "title": "NIST Cryogenic Material Properties: 6061-T6 Aluminum (UNS A96061)",
      "type": "database",
      "url": "https://trc.nist.gov/cryogenics/materials/6061%20Aluminum/6061_T6Aluminum_rev.htm"
    },
    {
      "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: Bauxite and Alumina",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-bauxite-alumina.pdf",
      "year": 2026
    },
    {
      "title": "Alloys International: 6061 grade page (UNS A96061, W.Nr 3.3211, EN AW-6061 and commonly ordered AMS specifications)",
      "type": "datasheet",
      "url": "https://alloysintl.com/inventory/aluminum-alloys/aluminum-6061/"
    },
    {
      "title": "SAE AMS4027G: Aluminum Alloy Sheet and Plate, 6061 (-T6 Sheet, -T651 Plate), SAE page",
      "type": "standard",
      "url": "https://saemobilus.sae.org/content/ams4027g"
    },
    {
      "title": "SAE AMS4150M: Aluminum Alloy, Extrusions and Rings, 6061-T6, SAE page",
      "type": "standard",
      "url": "https://saemobilus.sae.org/standards/ams4150m-aluminum-alloy-extrusions-rings-10mg-060si-028cu-020cr-6061-t6-solution-precipitation-heat-treated"
    }
  ],
  "gaps": [
    "No vacuum outgassing (TML and CVCM), atomic-oxygen erosion, thermal-vacuum or flight result for bare 6061-T6 was found in an openly readable source; the NASA outgassing database entry for it was not located.",
    "Minimum guaranteed (design allowable) strengths were not found in an open source; the strengths here are Aluminum Association typical values that the datasheet marks NOT FOR DESIGN. MMPDS and MIL-HDBK-5 are not openly available.",
    "Cryogenic strength, elongation and fracture toughness at 77 K and 4 K were not found as values (the NASA handbook gives them only as graphs, and a 2023 Springer paper was not readable); only a calculated thermal conductivity at 77 K is given.",
    "Radiation: the NASA handbook has a table of neutron-irradiation effects on tensile properties, but its text says nuclear data were found only for 6063 while the table is headed 6061, so it was not used.",
    "No safety data sheet for the 6061 alloy was opened. PubChem GHS data for aluminium and magnesium metal is recorded as element-level hazards only; dust and fumes from cutting or welding are not recorded.",
    "Stress-corrosion cracking susceptibility rating (NASA MSFC-STD-3029) was not opened; only coating advice from the 1972 handbook is recorded.",
    "Galvanic corrosion rates for specific metal pairs were not extracted (NASA TP-2236, a scanned report on 6061-T6 coupled to graphite-epoxy, was found but not read).",
    "Crustal abundance and supply of the alloying elements (magnesium, silicon, copper, chromium) were not looked up.",
    "The original ASM MatWeb page (asm.matweb.com) could not be reached; the datasheet values come from a printed copy hosted by Quickparts.",
    "Designations not found in a source read in this run: ASTM B209, B221, B211 and B210 for 6061 (no readable page printed them), DIN AlMg1SiCu, JIS A6061, AFNOR, GB and BS. Not listed as other grades or unconfirmed: AlMgSi1 (Alloys International prints it beside EN AW-6061, but the ASM datasheet gives AlMg1SiCu for this grade and EN 573 was not read) and AD-33 (Russia), a key word on the ASM datasheet that the source does not call the same grade. Not reached: Aluminum Association Teal Sheets, Constellium 6061 page, Aalco 6061 datasheet (404), TW Metals (bot check, 403) and McMaster-Carr (JavaScript only). The Kaiser sheet (Rev. 05/06, Protolabs copy) prints only 'Alloy 6061'. Product form of AMS 4021, 4022, 4023, 4026 and 4115 was not read."
  ],
  "story": {
    "why": "Aluminium alloy 6061 is a wrought, heat-treatable aluminium alloy. Wrought means it is worked into plate, bar, tube or shapes by rolling, extruding or forging rather than cast to shape. Its main additions are magnesium (0.8 to 1.2 wt%) and silicon (0.4 to 0.8 wt%), with smaller amounts of copper and chromium. These form a magnesium silicide compound, Mg2Si, which the NASA handbook identifies as the primary precipitation-hardening agent: tiny particles precipitate inside the metal on heat treatment and make it harder for atomic planes to slip, which raises strength. A temper is a code for the heat treatment and working given to the metal, and this profile concerns the T6 and T651 tempers, which the datasheet lists together. Because the alloying content is low, the alloy keeps many properties of pure aluminium, including a protective oxide film and good corrosion resistance. That combination of moderate strength, low density and ready fabrication explains why it is a common structural alloy.",
    "uses": [
      {
        "where": "Launch vehicle and spacecraft structures",
        "line": "The 1972 NASA handbook states that aluminium alloys have been used in both structural and nonstructural applications in launch vehicles and spacecraft with excellent success, because they are relatively insensitive to degradation in typical space environment conditions."
      },
      {
        "where": "Tested on the ground as propellant tank walls",
        "line": "NASA tested simulated propellant tanks made of 6061-T3 sheet, with walls 0.020 to 0.125 inch thick, by firing projectiles through them. No interaction occurred between the tank wall and liquid oxygen or hydrazine. This was a ground test, not a flight."
      },
      {
        "where": "Fittings and mechanical parts",
        "line": "The ASM datasheet lists aircraft fittings, couplings, hinge pins, valves, hydraulic and brake pistons, electrical fittings and marine hardware among typical applications."
      }
    ],
    "can_do": [
      {
        "label": "Strength",
        "line": "In the T6 and T651 tempers the typical tensile yield strength (the stress at which permanent deformation begins) is 276 MPa and the typical ultimate tensile strength (the highest stress before fracture) is 310 MPa. These are Aluminum Association typical values, which the datasheet marks not for design. Elongation at break is 17% for a 1/2 inch (12.7 mm) diameter specimen.",
        "scope": "material",
        "value": "276 MPa yield"
      },
      {
        "label": "Weight and stiffness",
        "line": "Density is 2.7 g/cm3 and the modulus of elasticity, a measure of stiffness, is 68.9 GPa (average of tension and compression). The fatigue strength is 96.5 MPa after 500,000,000 cycles of completely reversed stress in an RR Moore rotating-beam test.",
        "scope": "material",
        "value": "2.7 g/cm3"
      },
      {
        "label": "Heat conduction",
        "line": "Thermal conductivity at 77 °F is 167 W/(m·K), the rate at which heat flows through the metal per metre of thickness and per kelvin of temperature difference. Evaluating the NIST curve fit at 77 K gives 83.5 W/(m·K), so conduction is lower at very low temperature.",
        "scope": "material",
        "value": "167 W/(m·K)"
      },
      {
        "label": "Thermal expansion",
        "line": "Between 68 and 212 °F the mean coefficient of thermal expansion is 23.6 ppm/K, meaning a length changes by 23.6 millionths for each kelvin of temperature change. A part bolted to a material that expands less will be stressed when the temperature changes.",
        "scope": "material",
        "value": "23.6 ppm/K"
      },
      {
        "label": "Heat radiation from the surface",
        "line": "The NASA handbook gives an emissivity (the fraction of ideal black-body radiation a surface emits) of 0.035 to 0.07 in air at 77 °F. The surface condition is not stated, and coatings or oxide growth would change it.",
        "scope": "material",
        "value": "0.035 to 0.07"
      }
    ],
    "compare": "The record supports only a limited comparison. The USGS lists composites as substitutes for aluminium in aircraft fuselages and wings, and composites, magnesium, steel and titanium in ground transportation. It says copper can replace aluminium in electrical and heat-exchange uses. This profile holds no strength-per-mass numbers for those alternatives, so it does not rank them.",
    "compare_rows": [
      {
        "label": "Density",
        "benchmark": "density",
        "scope": "material"
      },
      {
        "label": "Thermal conductivity",
        "benchmark": "thermal_conductivity",
        "scope": "material"
      },
      {
        "label": "Thermal expansion",
        "benchmark": "cte",
        "scope": "material"
      }
    ],
    "handling": [
      "Keep it away from strong alkalis and from hydrochloric and hydrofluoric acid.",
      "Avoid contact with more noble metals in wet or salty conditions, or isolate them from the aluminium.",
      "Paint topcoats are the most effective protection against stress-corrosion cracking, according to the handbook.",
      "Read the supplier's safety data sheet before cutting, grinding or welding."
    ],
    "good_for": [
      "Light structures that need moderate strength. Typical yield strength is 276 MPa at a density of 2.7 g/cm3.",
      "Corrosion resistance in air. The NASA handbook calls 6061 the best of the heat-treatable aluminium alloys, and says its resistance does not depend on temper.",
      "Heat spreading. Thermal conductivity is 167 W/(m·K) at 77 °F."
    ],
    "watch_out": [
      "Contact with more noble metals in wet or salty conditions. Galvanic coupling generally produces severe attack on the aluminium.",
      "Strong alkalis and hydrochloric or hydrofluoric acid attack the alloy.",
      "The strength values here are typical, not design allowables, and the datasheet marks them not for design.",
      "The melting range is 582 to 652 °C, and no vacuum outgassing, atomic-oxygen, flight or cryogenic strength values were found for this profile."
    ],
    "verdict": "6061-T6 is a light, workable structural alloy with a long record in launch vehicles and spacecraft and good corrosion resistance in air. Its weak points in the record are galvanic coupling, strong alkalis and acids, and the lack of design-grade or space-environment numbers here.",
    "recipe": {
      "line": "Wrought Al-Mg-Si alloy. Composition limits from the Aluminum Association data sheet: magnesium 0.8 to 1.2 wt%, silicon 0.4 to 0.8 wt%, copper 0.15 to 0.4 wt% and chromium 0.04 to 0.35 wt%, with aluminium as the balance. Magnesium and silicon form Mg2Si, which the NASA handbook names as the main precipitation-hardening agent (heat treatment to T6 or T651).",
      "parts": [
        {
          "name": "Aluminium",
          "symbol": "Al",
          "role": "The matrix of the alloy; its thin oxide film gives the corrosion resistance.",
          "share_note": "balance (the rest)"
        },
        {
          "name": "Magnesium",
          "symbol": "Mg",
          "role": "With silicon forms Mg2Si, the main precipitation-hardening compound.",
          "share_percent": 0.8,
          "share_high": 1.2
        },
        {
          "name": "Silicon",
          "symbol": "Si",
          "role": "With magnesium forms Mg2Si, the hardening compound.",
          "share_percent": 0.4,
          "share_high": 0.8
        },
        {
          "name": "Copper",
          "symbol": "Cu",
          "role": "Minor addition inside the composition limits printed on the data sheet.",
          "share_percent": 0.15,
          "share_high": 0.4
        },
        {
          "name": "Chromium",
          "symbol": "Cr",
          "role": "Minor addition inside the composition limits printed on the data sheet.",
          "share_percent": 0.04,
          "share_high": 0.35
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "No safety data sheet for the alloy was opened. Element-level GHS data for aluminium and magnesium from PubChem is in the hazards list, but the profile records no toxicity or dust data for the alloy.",
        "points": [
          {
            "label": "What the sources cover",
            "line": "The sources opened describe the metal's corrosion, fatigue and space-environment behaviour, not its effects on health. Before cutting, grinding or welding it, read the supplier's safety data sheet for the exact product."
          }
        ],
        "gap": "Hazard classification for 6061 as supplied, and for dust or fumes from machining or welding, was not found in a source we could open."
      },
      {
        "title": "If it fails",
        "lead": "These are failure routes named in a 1972 NASA handbook. They are statements and test summaries, not field incident data.",
        "points": [
          {
            "label": "Galvanic attack",
            "line": "Aluminium is strongly anodic to most other common metals, so when it touches them in a conductive liquid it is the part that corrodes. The handbook says this generally produces severe attack on the aluminium, especially in sea water."
          },
          {
            "label": "Fatigue in moist air",
            "line": "Water vapour speeds up the growth of fatigue cracks, especially at low stress intensities, but does not change how long a crack takes to start."
          },
          {
            "label": "Stress-corrosion cracking",
            "line": "Cracking can occur when a sustained surface stress and a corrosive environment act together. The handbook names epoxy-polyamide or polyurethane paint topcoats as the most effective protection and zinc-rich paints as the least effective."
          },
          {
            "label": "Cold welding in space",
            "line": "Space radiation tends to strip away surface films, which might cause loss of lubricity and an increased tendency of bare surfaces to cold weld, that is, to fuse when pressed together."
          }
        ]
      },
      {
        "title": "Handling and storage",
        "points": [
          {
            "label": "Chemicals to avoid",
            "line": "Strong alkalis such as sodium and potassium hydroxide, and hydrochloric and hydrofluoric acid, attack the alloy. The handbook lists several other severe environments, including aqua regia and various mercury compounds."
          },
          {
            "label": "Hydrazine fuels",
            "line": "6061-T6 resisted hydrazine fuels in 4 years of sealed storage at 110 °F (44 °C), but surfaces must be free of organic contamination or traces of catalytic metals or ions."
          },
          {
            "label": "Protection",
            "line": "Under normal conditions the alloy needs no surface protection. For severe environments, clad material (commonly clad with alloy 7072) or a paint topcoat can be used."
          }
        ]
      }
    ]
  },
  "updated": "2026-10-19",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 12,
    "unreachable": 1,
    "caveats": 3,
    "note": "Deepen pass on 2026-10-19 (no property changed): added story recipe from the ASM composition table, hazards from PubChem GHS for aluminium and magnesium, and two PubChem sources. Re-read by an AI assistant on 2026-10-17: 12 of 12 property values match their cited source (datasheet values re-read from the printed copy's extracted text; NASA values re-read from page images of the scanned handbook; the NIST value recomputed from the coefficients, which were fetched twice). 1 source page (asm.matweb.com) could not be reached. Caveats: strengths are typical values marked not for design; the 1972 handbook is old and its page text is scanned; the 77 K conductivity is a curve-fit value with a 0.5% stated fit error."
  },
  "sources": {
    "asm-6061": {
      "title": "ASM Material Data Sheet: Aluminum 6061-T6; 6061-T651 (printed copy, 12 May 2023)",
      "id": "ASM/MatWeb bassnum ma6061t6; data from Alcoa, Starmet and the Aluminum Association",
      "url": "https://quickparts.com/wp-content/uploads/2024/05/Aluminum-6061.pdf",
      "year": 2023,
      "kind": "datasheet",
      "license": "MatWeb terms of use (cited, not reproduced)"
    },
    "nasa-cr123772": {
      "title": "Materials Data Handbook: Aluminum Alloy 6061 (2nd edition), NASA CR-123772, Western Applied Research and Development for NASA Marshall Space Flight Center",
      "id": "NTRS 19720022808; NAS8-26644; May 1972",
      "url": "https://ntrs.nasa.gov/citations/19720022808",
      "year": 1972,
      "kind": "report",
      "license": "public domain (NASA)"
    },
    "nist-6061": {
      "title": "Material Properties: 6061-T6 Aluminum (UNS A96061), NIST Cryogenic Material Properties",
      "id": "NIST Cryogenics Technologies Group, curve fits for 4 to 300 K",
      "url": "https://trc.nist.gov/cryogenics/materials/6061%20Aluminum/6061_T6Aluminum_rev.htm",
      "kind": "database",
      "license": "NIST public web page"
    },
    "usgs-mcs2026-aluminum": {
      "title": "Mineral Commodity Summaries 2026, Aluminum",
      "id": "USGS MCS 2026, February 2026",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-aluminum.pdf",
      "year": 2026,
      "kind": "report",
      "license": "public domain (USGS)"
    },
    "usgs-mcs2026-bauxite": {
      "title": "Mineral Commodity Summaries 2026, Bauxite and Alumina",
      "id": "USGS MCS 2026, February 2026",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-bauxite-alumina.pdf",
      "year": 2026,
      "kind": "report",
      "license": "public domain (USGS)"
    },
    "usgs-crit2025": {
      "title": "About the 2025 List of Critical Minerals (USGS, final list of 60 minerals)",
      "id": "Final 2025 List of Critical Minerals, November 2025",
      "url": "https://www.usgs.gov/programs/mineral-resources-program/science/about-2025-list-critical-minerals",
      "year": 2025,
      "kind": "web",
      "license": "public domain (USGS)"
    },
    "ec-crm": {
      "title": "Critical raw materials (European Commission, list of 34 critical raw materials)",
      "id": "European Commission critical raw materials page",
      "url": "https://single-market-economy.ec.europa.eu/sectors/raw-materials/areas-specific-interest/critical-raw-materials_en",
      "kind": "web",
      "license": "European Commission web page"
    },
    "pubchem-al": {
      "title": "Aluminum, PubChem compound CID 5359268: Safety and Hazards, GHS Classification",
      "id": "PubChem CID 5359268 (PUG View JSON, read 2026-10-19); aggregated from ECHA C&L notifications",
      "url": "https://pubchem.ncbi.nlm.nih.gov/compound/5359268",
      "kind": "database",
      "license": "PubChem (NCBI) public data"
    },
    "pubchem-mg": {
      "title": "Magnesium, PubChem compound CID 5462224: Safety and Hazards, GHS Classification",
      "id": "PubChem CID 5462224 (PUG View JSON, read 2026-10-19); aggregated from ECHA C&L notifications",
      "url": "https://pubchem.ncbi.nlm.nih.gov/compound/5462224",
      "kind": "database",
      "license": "PubChem (NCBI) public data"
    },
    "alloysintl-6061": {
      "title": "Alloys International: 6061 grade page, with UNS, W.Nr and EN designations and a list of commonly ordered specifications",
      "id": "Alloys International (stockist), Ronkonkoma, NY; grade page for 6061 (UNS A96061)",
      "url": "https://alloysintl.com/inventory/aluminum-alloys/aluminum-6061/",
      "kind": "datasheet",
      "license": "supplier web page (cited, not reproduced)"
    },
    "sae-ams4027": {
      "title": "SAE AMS4027G: Aluminum Alloy Sheet and Plate 1.0Mg - 0.60Si - 0.30Cu - 0.25Cr (6061; -T6 Sheet, -T651 Plate), SAE page",
      "id": "SAE International material specification; the page shows AMS4027G and lists the current revision AMS4027P (2022-04-29)",
      "url": "https://saemobilus.sae.org/content/ams4027g",
      "kind": "standard",
      "license": "SAE International web page (cited, not reproduced)"
    },
    "sae-ams4150": {
      "title": "SAE AMS4150M: Aluminum Alloy, Extrusions and Rings 1.0Mg - 0.60Si - 0.28Cu - 0.20Cr - (6061-T6) Solution and Precipitation Heat Treated, SAE page",
      "id": "SAE International material specification; the page shows AMS4150M and lists the current revision AMS4150P (2024-03-27)",
      "url": "https://saemobilus.sae.org/standards/ams4150m-aluminum-alloy-extrusions-rings-10mg-060si-028cu-020cr-6061-t6-solution-precipitation-heat-treated",
      "kind": "standard",
      "license": "SAE International web page (cited, not reproduced)"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/aluminium-6061/"
}