spore: profile
id: titanium-5al-2-5sn
spore_version: 0.2
family: titanium-alloys
name: Titanium alloy Ti-5Al-2.5Sn (Grade 6)
abbreviation: Ti-5Al-2.5Sn
role: structural alloy
category: metals
type: titanium
summary: Ti-5Al-2.5Sn (Grade 6) is a near-alpha titanium alloy with 4.50 to 5.75 wt% aluminium and 2.00 to 3.00 wt% tin in the AMS 4910 plate and sheet spec. Annealed AMS 4910 plate and sheet have a density of 4.48 g/cm^3 and a tensile strength of 828 to 1034 MPa, per the Golden Sunbird Metals supplier page. The sources read give no cryogenic toughness value for this grade.
best_for: Welded structure and tank hardware where strength, weldability and stability at elevated temperature matter, as the two supplier pages describe it
weakest_at: 'Low-temperature toughness: no cryogenic toughness value for this grade was found in the sources read, and NASA says trace beta phase from iron and manganese can be detrimental to very low temperature properties'
identity:
  formula: 'Ti-5Al-2.5Sn: titanium with 4.50 to 5.75 wt% aluminium and 2.00 to 3.00 wt% tin (AMS 4910 composition); AMS 4966 forgings print 4.00 to 6.00 wt% aluminium and 2.00 to 3.00 wt% tin; iron 0.50 wt% max, oxygen 0.20 wt% max, carbon 0.08 wt% max, nitrogen 0.05 wt% max, hydrogen 0.020 wt% max, balance titanium. Nominal composition, no fixed chemical formula.'
  source: ams4910
  where: 'Chemical Composition (wt.%) table of AMS 4910 plate and sheet; aluminium range for AMS 4966 from its Chemical Composition table; Wikipedia Titanium alloy, Grade 6 entry: ''Contains 5% aluminium and 2.5% tin.'''
  designations:
    - system: AMS
      code: '4910'
      note: sheet, strip and plate, annealed
      source: ams4910
      where: 'Technical Specifications, Standard row: AMS4910 Ti5Al2.5Sn Titanium Alloy, Sheet, Strip, And Plate 5Al-2.5Sn Annealed'
    - system: AMS
      code: '4966'
      note: forgings, annealed
      source: ams4966
      where: 'Technical Specifications, Standard row: AMS4966 Ti5Al2.5Sn Titanium Alloy Forgings Annealed'
    - system: AMS
      code: '4926'
      note: bars and rings, same alloy, listed as a related product
      source: ams4966
      where: 'Related Products list: AMS4926 Ti5Al2.5Sn Titanium Alloy Bars and Rings'
tags:
  environments: []
  stresses:
    - extreme-cold
  applications:
    - structures
    - cryogenic-fuel
    - propulsion-and-tanks
properties:
  - benchmark: density
    label: Density, annealed plate and sheet
    value: 4.48
    unit: g/cm3
    scope: material
    conditions:
      form: plate and sheet, annealed (AMS 4910)
      unit_as_printed: g/cm^3
    method: Value printed in the Mechanical Properties (Annealed Condition) table of the supplier's AMS 4910 page
    status: ground
    source: ams4910
    where: 'Mechanical Properties table, Density row (also Technical Specifications, Density row: 4.48g/cm³)'
  - benchmark: density
    label: Density, annealed forgings
    value: 4.51
    unit: g/cm3
    scope: material
    conditions:
      form: forgings, annealed (AMS 4966)
      unit_as_printed: g/cm³
    method: Value printed in the Technical Specifications table of the supplier's AMS 4966 page
    status: ground
    source: ams4966
    where: Technical Specifications table, Density row (4.51g/cm³)
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, annealed plate and sheet
    value: 828
    value_high: 1034
    bound: range
    unit: MPa
    scope: material
    conditions:
      form: plate and sheet, annealed (AMS 4910)
      printed: 828 to 1034 MPa (120,000 to 150,000 psi)
    method: Range printed in the Mechanical Properties (Annealed Condition) table of the supplier's AMS 4910 page
    status: ground
    source: ams4910
    where: Mechanical Properties table, Tensile Strength row
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, annealed forgings (minimum)
    value: 827
    bound: lower
    unit: MPa
    scope: material
    conditions:
      form: forgings, annealed (AMS 4966)
      printed: 120 ksi (827 MPa) minimum
    method: Minimum printed in the Mechanical Properties table of the supplier's AMS 4966 page
    status: ground
    source: ams4966
    where: Mechanical Properties table, Tensile Strength row
  - benchmark: yield_strength
    label: Yield strength, annealed plate and sheet
    value: 759
    value_high: 1034
    bound: range
    unit: MPa
    scope: material
    conditions:
      form: plate and sheet, annealed (AMS 4910)
      test: 0.2% offset
      printed: 759 to 1034 MPa (110,000 to 150,000 psi)
    method: Range printed in the Mechanical Properties (Annealed Condition) table of the supplier's AMS 4910 page
    status: ground
    source: ams4910
    where: Mechanical Properties table, Yield Strength (0.2% Offset) row
  - benchmark: yield_strength
    label: Yield strength, annealed forgings (minimum)
    value: 758
    bound: lower
    unit: MPa
    scope: material
    conditions:
      form: forgings, annealed (AMS 4966)
      test: not stated on the page
      printed: 110 ksi (758 MPa) minimum
    method: Minimum printed in the Mechanical Properties table of the supplier's AMS 4966 page
    status: ground
    source: ams4966
    where: Mechanical Properties table, Yield Strength row
  - benchmark: elongation
    label: Elongation, annealed plate and sheet
    value: 10
    value_high: 20
    bound: range
    unit: '%'
    scope: material
    conditions:
      form: plate and sheet, annealed (AMS 4910)
      basis: in 4D
    method: Range printed in the Mechanical Properties (Annealed Condition) table of the supplier's AMS 4910 page
    status: ground
    source: ams4910
    where: Mechanical Properties table, Elongation (in 4D) row
  - benchmark: elongation
    label: Elongation, annealed forgings (minimum)
    value: 10
    bound: lower
    unit: '%'
    scope: material
    conditions:
      form: forgings, annealed (AMS 4966)
      printed: 10% minimum
    method: Minimum printed in the Mechanical Properties table of the supplier's AMS 4966 page
    status: ground
    source: ams4966
    where: Mechanical Properties table, Elongation row
  - benchmark: reduction_of_area
    label: Reduction of area, annealed plate and sheet
    value: 20
    value_high: 30
    bound: range
    unit: '%'
    scope: material
    conditions:
      form: plate and sheet, annealed (AMS 4910)
    method: Range printed in the Mechanical Properties (Annealed Condition) table of the supplier's AMS 4910 page
    status: ground
    source: ams4910
    where: Mechanical Properties table, Reduction of Area row
  - benchmark: reduction_of_area
    label: Reduction of area, annealed forgings (minimum)
    value: 20
    bound: lower
    unit: '%'
    scope: material
    conditions:
      form: forgings, annealed (AMS 4966)
      printed: 20% minimum
    method: Minimum printed in the Mechanical Properties table of the supplier's AMS 4966 page
    status: ground
    source: ams4966
    where: Mechanical Properties table, Reduction of Area row
  - benchmark: elastic_modulus
    label: Modulus of elasticity, annealed plate and sheet
    value: 110
    unit: GPa
    scope: material
    conditions:
      form: plate and sheet, annealed (AMS 4910)
      printed: About 110 GPa
    method: Value printed in the Mechanical Properties (Annealed Condition) table of the supplier's AMS 4910 page
    status: ground
    note: Printed with 'About', so it is a typical figure and not a limit.
    source: ams4910
    where: Mechanical Properties table, Modulus of Elasticity row
  - benchmark: elastic_modulus
    label: Modulus of elasticity, annealed forgings
    value: 103
    unit: GPa
    scope: material
    conditions:
      form: forgings, annealed (AMS 4966)
      printed: 103 GPa
    method: Value printed in the Mechanical Properties table of the supplier's AMS 4966 page
    status: ground
    source: ams4966
    where: Mechanical Properties table, Modulus of Elasticity row
  - benchmark: poissons_ratio
    label: Poisson's ratio, annealed forgings
    value: 0.34
    unit: '-'
    scope: material
    conditions:
      form: forgings, annealed (AMS 4966)
    method: Value printed in the Mechanical Properties table of the supplier's AMS 4966 page
    status: ground
    source: ams4966
    where: Mechanical Properties table, Poisson's Ratio row
  - benchmark: max_service_temp
    label: Elevated-temperature strength retention (supplier statement)
    value: 480
    bound: upper
    unit: °C
    scope: material
    conditions:
      form: forgings (AMS 4966)
      basis: 'supplier wording: good strength retention and stability up to approximately 480°C / 896°F'
    method: Supplier Features list; no test method, exposure time or strength value is printed with it
    status: ground
    source: ams4966
    where: Features list, elevated-temperature bullet
  - benchmark: beta_transus
    label: Alpha to beta transus
    value: 1875
    unit: degF
    scope: material
    conditions:
      basis: printed as 'about 1875 F' in NASA's text for Ti-5Al-2.5Sn
      composition: Ti-5Al-2.5Sn
    method: Stated in the alpha alloy section of NASA Technical Memorandum X-53445 (1966)
    status: ground
    note: beta_transus is not in property-canon.yaml; it is a short snake_case name.
    source: nasa-tmx53445
    where: Alpha Alloy Ti-5Al-2.5Sn section, Structure paragraph
corrosion:
  - environment: Seawater and aggressive industrial environments (supplier claim)
    headline: The supplier claims reliable corrosion resistance in seawater; no corrosion rate is printed.
    effect: The AMS 4910 supplier page lists reliable corrosion resistance in seawater and aggressive industrial environments as a feature. No test, exposure time or corrosion rate is printed with it.
    rating: low
    conditions:
      basis: qualitative supplier claim, not a test result
      form: plate and sheet, annealed (AMS 4910)
    source: ams4910
    where: Features list
  - environment: Seawater, chloride solutions and acids (supplier claim)
    headline: The forging supplier claims strong corrosion resistance; no corrosion rate is printed.
    effect: The AMS 4966 supplier page lists strong corrosion resistance in seawater, chloride solutions, acids and other demanding environments as a feature. No test data are printed with it.
    rating: low
    conditions:
      basis: qualitative supplier claim, not a test result
      form: forgings, annealed (AMS 4966)
    source: ams4966
    where: Features list
risks:
  hazards:
    - text: PubChem records titanium (CID 23963) as Not Classified under GHS, reported as not meeting GHS hazard criteria by 606 of 808 companies. That record covers the element titanium, not this alloy grade.
      ghs: []
      source: pubchem-ti
      where: Safety and Hazards, GHS Classification
    - text: PubChem's physical description of dry titanium powder says it can be easily ignited and burns with an intense flame, and that very fine powder may be ignited by sparks. That describes the powder, not the plate, sheet, forgings or bar in this profile.
      ghs: []
      source: pubchem-ti
      where: Physical Description entry in the PubChem record for titanium
  failure_risks:
    - mode: Lower room-temperature ductility after heating into the beta field
      trigger: Heating into the beta field without subsequent working in the alpha field
      consequence: NASA says this causes lower ductility at room temperature, with little effect on tensile strength properties.
      source: nasa-tmx53445
      where: Alpha Alloy Ti-5Al-2.5Sn section, annealing paragraph, and Table III discussion
    - mode: Loss of very low temperature properties from trace beta phase
      trigger: Trace beta phase stabilised by iron and manganese impurities
      consequence: NASA says this small amount of beta phase can be detrimental to very low temperature properties. A low interstitial (ELI) grade with lower iron and manganese content can be used for those applications.
      source: nasa-tmx53445
      where: Alpha Alloy Ti-5Al-2.5Sn section, Structure paragraph
  side_effects: []
  handling:
    - text: 'Stress relief: NASA says stress-relief annealing is ''normally conducted in the 1000 to 1200 F temperature range for 1/4 to 1 hour followed by air cooling''.'
      source: nasa-tmx53445
      where: Alpha Alloy Ti-5Al-2.5Sn section, Stress-Relief Annealing paragraph
    - text: 'Melting practice for the AMS 4910 product: multiple melts, the first by vacuum consumable electrode, non-consumable electrode, electron beam cold hearth or plasma arc cold hearth practice, and later melts by vacuum arc remelting (VAR). Alloy additions are not permitted in the final VAR melt.'
      source: ams4910
      where: Technical Specifications, Melting Practice row
  mitigations:
    - text: For very low temperature service, NASA says the ELI grade with lower iron and manganese can be used. The ELI grade is a different grade and is not profiled here.
      source: nasa-tmx53445
      where: Alpha Alloy Ti-5Al-2.5Sn section, Structure paragraph
uses:
  - application: structures
    device: Airframe forgings, brackets and fittings
    example: The AMS 4966 supplier page lists aircraft structural components such as brackets, fittings and airframe forgings.
    source: ams4966
    where: Applications list
  - application: structures
    device: Airframe components, brackets and panels from plate and sheet
    example: The AMS 4910 supplier page lists aerospace structural parts such as airframe components, brackets, panels and load-bearing fabricated parts.
    source: ams4910
    where: Applications list
  - application: cryogenic-fuel
    device: Liquid hydrogen tanks and cryogenic containers
    example: The AMS 4910 supplier page lists cryogenic equipment including liquid hydrogen tanks and cryogenic containers. This is a supplier application list, not a flight record.
    source: ams4910
    where: Applications list
  - application: propulsion-and-tanks
    device: Gas turbine engine casings and rings
    example: The AMS 4910 supplier page lists gas turbine engine casings and rings where strength, stability and heat resistance are important.
    source: ams4910
    where: Applications list
supply:
  - subject: Titanium sponge metal (feedstock for mill products)
    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 List of Critical Minerals (titanium entry)
        listed: true
      - list: EU critical raw materials list (Titanium metal entry, Regulation (EU) 2024/1252)
        listed: true
    recycling: 'USGS: consumption data for titanium scrap metal for the titanium metal industry were withheld, because survey responses were limited.'
    substitutes:
      - 'USGS: few materials possess titanium metal''s strength-to-weight ratio and corrosion resistance; aluminum, nickel, specialty steels and zirconium alloys may be substituted where corrosion resistance is required.'
    source: usgs-mcs2026-titanium
    where: 'World Sponge Metal Production table, 2025 column (China 260,000 t; Japan 53,000 t; Russia 25,000 t; Kazakhstan 16,000 t; Saudi Arabia 12,000 t; world total rounded 370,000 t). Shares calculated by Space Mushroom against the 370,000 t rounded total; USGS does not print them. Critical lists: USGS and European Commission pages (see sources).'
  - subject: Titanium (crustal abundance)
    abundance: 5,650 ppm in the Earth's crust (USGS Professional Paper 1802-A, Table A1, citing Jefferson Science Associates, 2014)
    source: usgs-pp1802a
    where: Table A1, Crustal abundances of mineral commodities (elements)
media: []
documents:
  - title: 'Mineral Commodity Summaries 2026: Titanium and Titanium Dioxide (USGS, February 2026)'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-titanium.pdf
    year: 2026
  - title: AMS4910 Ti5Al2.5Sn titanium alloy plate and sheet, supplier page (Golden Sunbird Metals)
    type: datasheet
    url: https://gsalloy.com/?p=1252
  - title: AMS4966 Ti5Al2.5Sn titanium alloy forgings, supplier page (Golden Sunbird Metals)
    type: datasheet
    url: https://gsalloy.com/?p=1272
  - title: 'PubChem: Titanium (CID 23963), GHS classification and physical description'
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/compound/23963
    year: 2025
  - title: 'NASA Technical Memorandum X-53445: Heat Treatment of Titanium and Titanium Alloys (1966)'
    type: report
    url: https://ntrs.nasa.gov/citations/19660015720
    year: 1966
gaps:
  - No UNS number is printed for this grade on any source read; the supplier pages list AMS numbers only.
  - The ELI version (printed as Ti5Al2.5Sn ELI and AMS 4924 on the AMS 4966 page's related products list) is a different grade and is not profiled. Its toughness at liquid-hydrogen temperature was not found in any source read.
  - No cryogenic tensile, yield or fracture toughness value for this grade was found. The 1966 NASA report contains no low-temperature test data for this alloy.
  - NASA heritage in cryogenic propellant tanks and use in liquid hydrogen turbopumps (planning notes) are not shown by any source read.
  - Thermal conductivity, specific heat, coefficient of thermal expansion and melting range were not found; the supplier pages state that these are not given.
  - Fatigue, creep and room-temperature fracture toughness were not found in the sources read. The hardness limit printed on the AMS 4966 page is not profiled as a benchmark.
  - 'Corrosion: no measured corrosion rate, exposure test or seawater data were found; both corrosion entries are supplier claims.'
  - Hazard data cover titanium in general (PubChem) and titanium powder. No safety data sheet for the solid alloy was read.
  - Aluminium, tin and iron supply shares and an aluminium or tin mine-production table were not read in this run.
  - The Grade 6 datasheet from MatWeb, linked from the Wikipedia article, could not be opened because the site showed a bot check.
  - No flight, vacuum or space-exposure data for this alloy were found.
  - reduction_of_area is not in property-canon.yaml; it is a short snake_case name.
sources:
  ams4910:
    title: AMS4910 Ti5Al2.5Sn Titanium Alloy Plate and Sheet (supplier page, Golden Sunbird Metals)
    id: AMS 4910, annealed plate, sheet and strip
    url: https://gsalloy.com/?p=1252
    kind: web
    license: supplier web page, linked not reproduced
  ams4966:
    title: AMS4966 Ti5Al2.5Sn Titanium Alloy Forgings (supplier page, Golden Sunbird Metals)
    id: AMS 4966, annealed forgings
    url: https://gsalloy.com/?p=1272
    kind: web
    license: supplier web page, linked not reproduced
  usgs-mcs2026-titanium:
    title: 'Mineral Commodity Summaries 2026: Titanium and Titanium Dioxide'
    id: USGS MCS 2026, February 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-titanium.pdf
    year: 2026
    kind: report
    license: public domain (USGS)
  usgs-pp1802a:
    title: 'Critical Mineral Resources of the United States: An Introduction (Professional Paper 1802-A), Table A1, crustal abundances'
    id: USGS PP 1802-A
    url: https://pubs.usgs.gov/pp/1802/a/pp1802a.pdf
    year: 2017
    kind: report
    license: public domain (USGS)
  usgs-crit2025:
    title: About the 2025 List of Critical Minerals (USGS)
    id: Final 2025 List of Critical Minerals
    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 under Regulation (EU) 2024/1252)
    id: Regulation (EU) 2024/1252
    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 compound record, Titanium (CID 23963)
    id: CID 23963
    url: https://pubchem.ncbi.nlm.nih.gov/compound/23963
    year: 2025
    kind: database
    license: public domain (NCBI)
  wiki-ti-alloy:
    title: Titanium alloy (Wikipedia), Grade 6 entry
    url: https://en.wikipedia.org/wiki/Titanium_alloy
    kind: web
    license: CC BY-SA 4.0
  nasa-tmx53445:
    title: Heat Treatment of Titanium and Titanium Alloys (NASA Technical Memorandum X-53445, F. F. Schmidt and R. A. Wood)
    id: NASA TM X-53445; NTRS 19660015720
    url: https://ntrs.nasa.gov/citations/19660015720
    year: 1966
    kind: report
    license: public domain (NASA)
license: CC-BY-4.0
updated: '2026-11-01'
review:
  status: draft
  method: assistant
  checked_values: 15
  unreachable: 1
  caveats: 0
  note: 'Read by an AI assistant on 2026-11-01: values copied from the two supplier AMS pages and the NASA report as printed. The MatWeb Grade 6 datasheet could not be opened (bot check). No cryogenic data found.'
story:
  why: Ti-5Al-2.5Sn is a titanium alloy that suppliers sell for aircraft structure, cryogenic tanks and gas turbine parts. Its appeal is the combination of weldability, stable strength at elevated temperature and corrosion resistance, as the AMS 4910 and AMS 4966 suppliers describe it. NASA's 1966 report calls it an alpha alloy, which it describes as essentially all alpha phase, and says heat treatment has little or no effect on its mechanical properties. The sources read do not give cryogenic toughness values for this grade.
  uses:
    - where: Aircraft structure
      line: The AMS 4966 supplier page lists brackets, fittings and airframe forgings. The AMS 4910 page lists airframe components, brackets and panels from plate and sheet.
    - where: Liquid hydrogen tanks
      line: The AMS 4910 supplier page lists cryogenic equipment, including liquid hydrogen tanks and cryogenic containers. That is a supplier application list, not a flight record.
    - where: Gas turbine casings and rings
      line: The AMS 4910 supplier page lists gas turbine engine casings and rings where strength, stability and heat resistance matter. Wikipedia says the alloy is used in airframes and jet engines.
  can_do:
    - label: Density
      benchmark: density
      line: Annealed AMS 4910 plate and sheet have a density of 4.48 g/cm³. Annealed AMS 4966 forgings have a density of 4.51 g/cm³.
    - label: Strength
      benchmark: yield_strength
      line: Annealed AMS 4910 plate and sheet have a 0.2% offset yield strength of 759 to 1034 MPa and a tensile strength of 828 to 1034 MPa. Annealed AMS 4966 forgings have a minimum yield strength of 758 MPa and a minimum tensile strength of 827 MPa.
    - label: Ductility
      benchmark: elongation
      line: Elongation is 10% to 20% in AMS 4910 plate and sheet, measured in 4D. AMS 4966 forgings have a minimum of 10%.
    - label: Elevated temperature
      benchmark: max_service_temp
      line: The AMS 4966 supplier page says strength is retained well up to about 480 °C. That is a supplier statement with no test method printed.
  compare: Ti-5Al-2.5Sn is an alpha alloy. NASA's 1966 report classes it as an alpha alloy and Ti-6Al-4V as an alpha-beta alloy, so the Ti-6Al-4V family carries beta-phase content that this alloy does not. The sources read here give no strength or density values for Ti-6Al-4V, so this profile does not compare numbers across the two grades. The table compares this grade's own properties.
  compare_rows:
    - label: Density
      benchmark: density
    - label: Yield strength
      benchmark: yield_strength
    - label: Elongation
      benchmark: elongation
  handling:
    - 'Stress relief: NASA says stress-relief annealing is normally done at 1000 to 1200 F for 1/4 to 1 hour, followed by air cooling.'
    - 'Melting: the AMS 4910 product is melted several times, with the last melt by vacuum arc remelting, and no alloy additions are made in that final melt.'
    - If toughness at very low temperature matters, NASA says the ELI grade, with lower iron and manganese, is the one to use. This profile does not cover the ELI grade.
  good_for:
    - Welded structure and parts that must keep strength at moderately elevated temperature, as the AMS 4910 and AMS 4966 suppliers describe them. No test data are printed with that claim.
    - Cryogenic tanks where weldability and ductility are wanted. NASA supports the low-interstitial version for very low temperatures.
  watch_out:
    - Low-temperature toughness is not measured in any source read. The cryogenic claims are supplier statements.
    - The standard grade allows up to 0.20 wt% oxygen and 0.50 wt% iron. The ELI version is a different grade with tighter limits.
    - Strength depends on the product form and spec. Plate and sheet (AMS 4910) and forgings (AMS 4966) print different minimums.
  verdict: Ti-5Al-2.5Sn is a documented, weldable alpha alloy with supplier-stated cryogenic and corrosion performance. This profile holds no cryogenic toughness or corrosion-rate values, so those claims rest on supplier statements.
  recipe:
    line: Ti-5Al-2.5Sn is titanium alloyed with about 5% aluminium and 2.5% tin, per Wikipedia. AMS 4910 plate and sheet sets aluminium at 4.50 to 5.75 wt% and tin at 2.00 to 3.00 wt%, with the balance titanium. AMS 4966 forgings set aluminium at 4.00 to 6.00 wt%. The product is melted several times, with the last melt by vacuum arc remelting.
    parts:
      - name: Titanium
        symbol: Ti
        role: The base metal; the balance of the alloy by weight.
        share_note: remainder
      - name: Aluminium
        symbol: Al
        role: Main alloying element with tin in this near-alpha alloy.
        share_percent: 4.5
        share_high: 5.75
        source: ams4910
        where: Chemical Composition table, Aluminum row
      - name: Tin
        symbol: Sn
        role: Neutral alloying element, as the Wikipedia definition of alpha alloys names tin.
        share_percent: 2
        share_high: 3
        source: ams4910
        where: Chemical Composition table, Tin row
      - name: Iron
        symbol: Fe
        role: Impurity. NASA says iron and manganese impurities stabilise a small amount of beta phase.
        share_note: 0.50 wt% max
        source: ams4910
        where: Chemical Composition table, Iron row
      - name: Oxygen
        symbol: O
        role: Interstitial impurity; the standard grade allows up to this level.
        share_note: 0.20 wt% max
        source: ams4910
        where: Chemical Composition table, Oxygen row
  risk_groups:
    - title: For people
      level: 0
      verdict: Solid alloy not classified as hazardous
      lead: The PubChem record for titanium is Not Classified under GHS. Titanium powder is a different case.
      points:
        - label: Solid alloy
          line: PubChem reports titanium as Not Classified under GHS, from 606 of 808 company reports. The record covers the element, not this alloy grade.
        - label: Powder
          line: PubChem says dry titanium powder can be easily ignited and burns with an intense flame. That applies to powder, not to plate, sheet, forgings or bar.
    - title: Low-temperature use
      lead: NASA's 1966 report does not test this grade at low temperature.
      gap: No cryogenic toughness data for Ti-5Al-2.5Sn were found in the sources read.
      points:
        - label: Trace beta phase
          line: NASA says a small amount of beta phase, stabilised by iron and manganese impurities, can be detrimental to very low temperature properties. The ELI grade has lower iron and manganese.