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.
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'
  source: ti-grade23
  where: 'Table 1, chemical composition: Grade 23 column (UNS R56407) and ASTM F136 column (UNS R56401)'
  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
tags:
  environments: []
  stresses:
    - extreme-cold
  applications:
    - structures
    - propulsion-and-tanks
properties:
  - benchmark: density
    label: Density
    value: 4.42
    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
  - 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
  - benchmark: beta_transus
    label: Beta-transus temperature
    value: 966
    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
  - benchmark: thermal_conductivity
    label: Thermal conductivity
    value: 6.6
    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
  - benchmark: specific_heat
    label: Specific heat capacity
    value: 0.58
    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
  - benchmark: cte
    label: Mean coefficient of thermal expansion
    value: 9
    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
  - 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
  - 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
  - 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
  - benchmark: electrical_resistivity
    label: Electrical resistivity
    value: 1.68
    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
  - benchmark: ultimate_tensile_strength
    label: Ultimate tensile strength, annealed bar to ASTM B348
    value: 828
    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)
  - benchmark: yield_strength
    label: 0.2 % yield strength, annealed bar to ASTM B348
    value: 759
    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)
  - benchmark: elongation
    label: Elongation, annealed bar to ASTM B348
    value: 10
    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%
  - 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
  - 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
  - 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%
  - benchmark: fracture_toughness
    label: Fracture toughness K_Ic(J) at 293 K, research ELI forging
    value: 57.5
    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
  - benchmark: fracture_toughness
    label: Fracture toughness K_Ic(J) at 77 K, research ELI forging
    value: 42.9
    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
  - benchmark: fracture_toughness
    label: Fracture toughness K_Ic(J) at 4 K, research ELI forging
    value: 44.9
    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
  - benchmark: yield_strength
    label: 0.2 % yield strength at 293 K, research ELI forging
    value: 908
    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
  - benchmark: ultimate_tensile_strength
    label: Tensile strength at 293 K, research ELI forging
    value: 953
    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
  - benchmark: ultimate_tensile_strength
    label: Tensile strength at 77 K, research ELI forging
    value: 1502
    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
  - benchmark: reduction_of_area
    label: Reduction of area at 293 K, research ELI forging
    value: 41.5
    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
  - benchmark: reduction_of_area
    label: Reduction of area at 77 K, research ELI forging
    value: 22
    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
  - benchmark: reduction_of_area
    label: Reduction of area at 4 K, research ELI forging
    value: 27.2
    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
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.'
    us_position: The United States produced no titanium sponge in 2025; the last domestic sponge plant closed in 2024. Imports were an estimated 44,000 t in 2025 (Japan 73 %, Kazakhstan 13 %, Saudi Arabia 13 % through July), and net import reliance was 100 % (2025e).
    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.'
    us_position: Six primary smelters in five states (1.31 million tons per year of capacity) produced 660 thousand t in 2025e; net import reliance was 60 % (2025e); imports in 2021 to 2024 came mainly from Canada (56 %).
    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.'
    us_position: 'No primary mine production in the United States: Utah production ceased in early 2020 and was not restarted in 2025. Net import reliance was 41 % (2025e); ferrovanadium imports in 2021 to 2024 came mainly from Canada (50 %) and Austria (35 %).'
    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
supply_note: Shares are computed by the assistant from the printed tonnage and the printed world totals (USGS rounds its world totals); they are not printed by USGS.
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.'
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
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.'
composition:
  basis: weight percent, ASTM B265 and B348 Grade 23 column of the Titanium Industries Table 1
  source: ti-grade23
  where: Table 1, Chemical Composition, Grade 23 column; ASTM F136 column for H
  limits:
    - element: Al
      min: 5.5
      max: 6.5
    - element: V
      min: 3.5
      max: 4.5
    - element: Fe
      max: 0.25
    - element: O
      max: 0.13
    - element: C
      max: 0.08
    - element: 'N'
      max: 0.03
    - element: H
      max: 0.0125
  other_each_max: 0.1
  other_total_max: 0.4
  note: Titanium is the balance (Titanium Industries prints 88.09 to 91 %; UPMET prints 88.0 to 91.0 %). Titanium Industries prints N max 0.030, C max 0.080, H max 0.0125 for B265 and B348, and H max 0.012 for F136. Carpenter prints N max 0.050, H max 0.013 and O max 0.130. UPMET prints N max 0.03 and O max 0.013, which is very probably a typo for 0.13. Fe max 0.25 and C max 0.08 agree across Titanium Industries, UPMET and Carpenter.
story:
  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
        share_note: balance (the rest)
        role: Base metal. Most of the alloy is titanium, which gives low density and corrosion resistance.
        source: ti-grade23
        where: Table 1; balance implied by the other limits
      - name: Aluminium
        symbol: Al
        share_percent: 5.5
        share_high: 6.5
        role: Alpha stabiliser.
        source: ti-grade23
        where: Table 1, Al 5.5 to 6.5 %
      - name: Vanadium
        symbol: V
        share_percent: 3.5
        share_high: 4.5
        role: Beta stabiliser.
        source: ti-grade23
        where: Table 1, V 3.5 to 4.5 %
      - name: Iron
        symbol: Fe
        share_high: 0.25
        share_note: maximum 0.25 %
        role: Impurity with a maximum limit. The ELI limit is lower than the standard Ti-6Al-4V limit (see compare).
        source: ti-grade23
        where: Table 1, Fe maximum 0.25 %
      - name: Oxygen
        symbol: O
        share_high: 0.13
        share_note: maximum 0.13 %
        role: Interstitial with a maximum limit. The 1991 study found the lowest-oxygen alloy had the best ductility at 4 K.
        source: ti-grade23
        where: Table 1, O maximum 0.13 %; Carpenter prints O maximum 0.130
      - name: Carbon
        symbol: C
        share_high: 0.08
        share_note: maximum 0.080 %
        role: Interstitial with a maximum limit.
        source: ti-grade23
        where: Table 1, C maximum 0.080 %
      - name: Nitrogen
        symbol: 'N'
        share_high: 0.03
        share_note: maximum 0.030 % (Carpenter prints 0.050 %)
        role: Interstitial with a maximum limit. Two suppliers print different limits.
        source: ti-grade23
        where: Table 1, N maximum 0.030 %
      - name: Hydrogen
        symbol: H
        share_high: 0.0125
        share_note: maximum 0.0125 % (B265 and B348); 0.012 % for F136
        role: Interstitial with a maximum limit.
        source: ti-grade23
        where: Table 1, H maximum 0.0125 % (B265/B348) and 0.012 % (F136)
  risk_groups:
    - title: For people
      level: 0
      verdict: Not classified in PubChem
      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).
    - 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).
  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
      benchmark: fracture_toughness
      value: 57.5 MPa√m at 293 K; 42.9 at 77 K; 44.9 at 4 K
      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.
    - label: Strength of annealed bar
      benchmark: yield_strength
      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).
    - label: Stiffness
      benchmark: elastic_modulus
      line: Young's modulus is 107 to 122 GPa at 20 degC and 95 to 111 GPa at 230 degC (UPMET).
    - label: Density
      benchmark: density
      line: Density is 4.42 g/cm3 at 22 degC (UPMET).
  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
    - label: Elastic modulus
      benchmark: elastic_modulus
    - label: Yield strength
      benchmark: yield_strength
  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.