Ti-6Al-2Sn-4Zr-2Mo
metaltitanium alloy — near-alpha
Ti-6-2-4-2Ti6242UNS R54620Grade 6 TitaniumAMS 4919 (sheet)ASTM B265 Gr.6
Composition — UNS R54620 / AMS 4919 / ASTM B265 Grade 6
| Element | Min % | Max % | Notes |
|---|---|---|---|
| Ti | bal. | balance | |
| Al | 5.50 | 6.500 | Alpha stabiliser; solid-solution strengthening |
| Sn | 1.80 | 2.200 | Solid-solution strengthening; negligible effect on transus; improves creep resistance |
| Zr | 3.60 | 4.400 | Solid-solution strengthening; reduces beta fraction; key to elevated-temperature creep resistance |
| Mo | 1.80 | 2.200 | Beta stabiliser (weak); solid-solution strengthening; reduces beta-transus slightly |
| Si | 0.06 | 0.100 | Inhibits silicide precipitation at grain boundaries during creep; very narrow range — critical to control |
| Fe | — | 0.250 | |
| O | — | 0.150 | Key interstitial — oxygen content is tightly controlled for near-alpha alloys to maintain toughness |
| N | — | 0.050 | |
| C | — | 0.050 | |
| H | — | 0.015 |
Mechanical & thermal properties — 3 conditions
| Property | LPBF as-built (XY) | LPBF STA (XY) — primary service condition | LPBF STA (Z) |
|---|---|---|---|
| Elastic modulus | — | 108–118 GPa | — |
| Yield strength (0.2%) | 950–1180 MPa | 950–1060 MPa | 820–950 MPa |
| Ultimate tensile strength | 1050–1280 MPa | 1050–1160 MPa | 900–1050 MPa |
| Elongation at break | 2.0–8.0 % | 8.0–14.0 % | 5.0–12.0 % |
| Hardness (HV) | — | 310–370 HV10 | — |
| Fatigue strength | — | 480–620 MPa | — |
| Density | 4.55 g/cm³ | — | — |
| Max service temperature | — | 450–540 °C | — |
Values shown as min–max where a spread is reported, otherwise as typical ± unit. Ranges reflect inter-source variation, not single-sample scatter. All values are for AM-processed specimens unless noted.
Engineering considerations
- STA cycle specification: solution treat at 900°C/1h (not above beta transus ~990°C — grain growth risk) + age 565°C/8h. Temperature tolerances ±15°C. Verify with hardness or microstructural checks on coupon specimens.
- Residual stress: Ti-6-2-4-2 develops high residual stress in LPBF similar to Ti-6Al-4V. Stress relieve (800°C/2h) before removal from build plate if distortion risk is high, then proceed to full STA.
- Creep design: use established wrought Ti-6-2-4-2 Larson-Miller creep data as conservative baseline. AM creep data is not yet published in peer-reviewed literature — generate test data for any creep-critical application.
- HIP recommendation: for fatigue-critical or fracture-critical applications, specify HIP (900°C/100 MPa/2h) before STA. Closes gas porosity that would otherwise initiate fatigue cracks. Required by most aerospace primes.
- Build orientation for rotating components: align primary load axis in XY plane. After STA, Z-direction properties are acceptable for most applications but design allowables should be based on Z-direction test data.
- Powder management: store under argon or vacuum; GRCop-84 oxygen pickup risk applies here too. Verify powder chemistry before reuse — oxygen limits are tighter for near-alpha alloys than alpha-beta.
Advantages
- Service temperature 450–500°C vs ~315°C for Ti-6Al-4V — opens mid-temperature aerospace applications
- Lower density (4.55 g/cm³) than Ni superalloys (8.2–8.9 g/cm³) — critical weight saving in rotating components
- LPBF enables net-shape or near-net-shape complex blades and vanes, reducing machining of this difficult-to-cut alloy
- Solid-solution strengthening (Zr, Mo, Sn) is stable — no precipitation dissolution risk during in-service thermal excursions
- Good oxidation resistance to 600°C in air (TiO₂ scale formation)
- Well-established wrought material heritage in GE90, CF6, and RB211 engine families provides comparative baseline
Limitations
- STA post-processing is mandatory — as-built properties are poor (brittle martensite, high residual stress)
- Less data available for AM-specific mechanical properties vs Ti-6Al-4V; design databases are sparse
- Lower ductility than Ti-6Al-4V STA (10% vs 15% typical elongation) — requires more conservative design allowables
- Higher material cost than Ti-6Al-4V powder due to Sn, Zr, Mo additions and smaller production volumes
- Near-alpha alloys are more difficult to hot-form than alpha-beta; this affects LPBF support structure removal
- No AM-specific material standard (no ASTM F equivalent to F2924 for Ti-6Al-4V)
- Fatigue data for LPBF condition is sparse — generate specific test data before creep-critical design
Typical applications
Turbofan engine compressor blades and vanes (intermediate pressure stages)Fan frame and nacelle structural componentsTurbine exhaust case structureAeroengine intermediate compressor discs (creep-critical)Supersonic aircraft structural panels exposed to aerodynamic heatingEngine nacelle and thrust reverser structureHigh-temperature fasteners and brackets in engine hot sections
Industries
aerospacedefence
Compatible AM processes (2)
Other metal materials
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Related calculators
LPBF Porosity PredictorPredict lack-of-fusion and keyhole porosity from laser parameters. Maps VED and normalised enthalpy to relative density and flags dangerous regimes.Powder Characterisation TrackerScore a powder batch against key qualification metrics — particle size distribution, flowability, apparent/tap density, moisture, and oxygen content.Surface Treatment SelectorRank post-print surface treatments (shot peening, electropolishing, tumbling, PVD, and more) against Ra target, material, fatigue criticality, and corrosion requirements.NDT SelectorSelect the right non-destructive testing method for your AM part. Inputs: material class, defect focus, geometry, production volume, and criticality. Ranked scorecard across CT, X-ray, UT, FPI, MPI, eddy current, and visual inspection with detection limits and standard references.HT AdvisorStandard stress-relief, solution, and aging cycles for AM metals (Ti-6Al-4V, IN718, 17-4PH, AlSi10Mg, 316L, CuCrZr) per AMS, ASTM F3301, and AMS 5664.FatigueS-N curve estimation for AM metals using the Basquin law. Accounts for surface roughness stress concentration (Kt from Ra), build direction anisotropy, and porosity factor.
Last reviewed: 2026-05-13 · v1 · Sources: special-metals-ti6242-2022, chan-2017-ti6242-lpbf, shahsavari-2021-ti6242-fatigue
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