Waspaloy®
metalnickel superalloy — γ'-precipitation-hardened
UNS N07001Alloy 685AMS 5544AMS 5704PWA 683Ni-Cr-Co superalloy
Composition — UNS N07001 / ASTM B637 / AMS 5544
| Element | Min % | Max % | Notes |
|---|---|---|---|
| Ni | bal. | balance | |
| Cr | 18.00 | 21.000 | Oxidation resistance and solid-solution strengthening; forms Cr₂O₃ scale |
| Co | 12.00 | 15.000 | Solid-solution strengthening; raises γ' solvus temperature for better high-T stability |
| Mo | 3.50 | 5.000 | Solid-solution strengthening; corrosion resistance in reducing environments |
| Al | 1.20 | 1.600 | γ' (Ni₃Al,Ti) former — primary precipitate strengthener |
| Ti | 2.75 | 3.250 | γ' former (combined Al+Ti drives γ' fraction); must be controlled for hot-cracking risk in LPBF |
| Zr | 0.02 | 0.120 | Grain boundary strengthening; carbide former |
| B | 0.00 | 0.010 | Grain boundary strengthening; key for creep resistance. Also contributes to hot-cracking risk in LPBF at high B content |
| C | 0.02 | 0.100 | M₂₃C₆ and MC carbides at grain boundaries — beneficial for creep but must not be excessive |
| Fe | — | 2.000 | |
| Mn | — | 0.100 | |
| Si | — | 0.150 | |
| Cu | — | 0.100 | |
| S | — | 0.015 | |
| P | — | 0.030 |
Mechanical & thermal properties — 3 conditions
| Property | LPBF stress-relieved (1050°C / 1h / AC) (XY) | LPBF SA + double-age (XY) — primary service condition | LPBF SA + double-age (Z) |
|---|---|---|---|
| Elastic modulus | — | 197–217 GPa | — |
| Yield strength (0.2%) | 700–870 MPa | 793–1000 MPa | 780–950 MPa |
| Ultimate tensile strength | 960–1150 MPa | 1207–1380 MPa | 1160–1320 MPa |
| Elongation at break | 12.0–28.0 % | 12.0–28.0 % | 10.0–26.0 % |
| Hardness (HV) | — | 365–430 HV10 | — |
| Fatigue strength | — | 500–690 MPa | — |
| Density | 8.19 g/cm³ | — | — |
| Thermal conductivity | 11.7 W/m·K | — | — |
| CTE | 12.8–14.2 µm/m·K | — | — |
| Max service temperature | — | 870 °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
- Hot-cracking mitigation strategy: (1) elevated preheat 200–400°C reduces thermal gradient; (2) island scan strategy reduces thermal accumulation; (3) low VED reduces heat input per unit volume; (4) support strategy that limits constraint at high-stress locations. Even with mitigations, 100% FPI + CT inspection of every Waspaloy part is strongly recommended before heat treatment.
- Heat treatment control: solution anneal at 1080°C ±10°C for exactly 4h is critical. Under-annealing (< 4h or < 1070°C) leaves primary γ' undissolved, reducing subsequent ageing response. Over-annealing (> 1100°C or > 6h) causes grain coarsening. Use vacuum or Ar atmosphere.
- Cracking detection: fluorescent penetrant inspection (FPI per ASTM E1417) after machining. Industrial CT scanning (0.1 mm resolution or better) is preferred for complex internal features. Do not accept parts with cracks > 0.5 mm before heat treatment.
- Comparison with IN718: choose Waspaloy when service temperature > 650°C and creep/fatigue governs design. Below 650°C, IN718 provides equivalent or better properties with lower processing risk and cost. If design allows downgrading from 850°C to 700°C service, IN718 may be substituted at significant cost and risk reduction.
- Alloy stability: γ' coarsening rate increases sharply above 870°C. If temperature excursions above 870°C are possible in service, use a more stable alloy (René 88DT, IN939, CMSX-4) or account for γ' coarsening in life prediction.
- Surface treatment: as-built LPBF surfaces have Ra 10–20 µm — unacceptable for rotating disc faying surfaces (require Ra < 1.6 µm per most aerospace standards). Plan for full machining of all functional surfaces. Electropolishing or grit blasting for non-machined surfaces before coating.
- Powder reuse: Waspaloy powder is susceptible to Al/Ti oxidation during LPBF processing. Characterise each reuse lot for chemistry (ICP-OES) and morphology (ASTM F3049). Limit reuse to 10 cycles or less; recalibrate oxygen content after each cycle.
Advantages
- Outstanding combination of creep strength and fatigue resistance at 700–870°C — surpasses IN718 above 650°C
- γ' precipitation strengthening provides superior strength retention at high temperature vs. solid-solution alloys
- Good oxidation resistance to ~1000°C in air and combustion gases
- LPBF enables complex internal cooling passages for compressor disc cooling — not achievable in forging
- Established wrought property database (AMS 5544) provides design baseline for LPBF qualification
- No Laves phase issues (unlike IN718) — no Nb-rich eutectic segregation during solidification
Limitations
- High hot-cracking susceptibility in LPBF — high (Al+Ti) content drives γ' precipitation during layer reheating, causing strain-age cracking (SAC)
- Requires elevated preheat (200–400°C) and tightly controlled scan strategy — significantly higher LPBF complexity than IN718
- Limited LPBF parameter databases — fewer published studies vs. IN718 or IN625; higher parameter development investment needed
- Mandatory full heat treatment (SA + double-age) — complex 3-step process with tight temperature control (±10°C)
- Residual microcracking is difficult to detect without CT or FPI — quality assurance cost is high
- Very high powder cost (premium Ni superalloy with Co) — 2–3× more expensive than IN718 powder
- Restricted to LPBF — DED is theoretically possible but cracking risk is higher due to lower cooling rates
- Hot-cracking risk is exacerbated by high build temperatures — careful thermal management during build is essential
Typical applications
Gas turbine compressor discs and impellers — primary application exploiting high fatigue strength at 700–870°CTurbine disc bores and bolt holes — where fatigue crack initiation is criticalCompressor rotor blades — stationary and rotatingHigh-temperature fasteners and bolts for gas turbine assembliesCombustion casing components operating at intermediate temperaturesIndustrial gas turbine hot section componentsRocket engine turbopump components operating at cryogenic-to-hot cycle conditions
Industries
aerospaceenergydefence
Standards & certifications
ASTM-F3049established
Powder feedstock characterisation for LPBF Waspaloy
aerospaceenergy
No dedicated AM Waspaloy standard. Aerospace qualification follows OEM-specific plans. AMS 5544 (wrought) used as property benchmark.
NADCAP-AC7110-14established
NADCAP accreditation for metallic AM parts — required for aerospace flight-critical Waspaloy parts
aerospace
Compatible AM processes (1)
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Related calculators
VEDCompute LPBF VED from power, scan speed, hatch, and layer thickness. Includes process windows for common alloys.Melt PoolLPBF / DED melt pool depth, width, and cooling rate from the Rosenthal moving heat source solution. Absorptivity, thermal diffusivity, and solidification velocity.Laser ParamsDerive LPBF process parameters from target VED and melt-pool stability constraints. Power–speed–hatch–layer sensitivity matrix with keyholing and balling risk zones.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.DistortionEstimate residual stress and distortion risk index (σ/σ_y) for LPBF and DED builds. Mercelis-Kruth model with preheat sensitivity table.LPBF Porosity PredictorPredict lack-of-fusion and keyhole porosity from laser parameters. Maps VED and normalised enthalpy to relative density and flags dangerous regimes.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.Surface Treatment SelectorRank post-print surface treatments (shot peening, electropolishing, tumbling, PVD, and more) against Ra target, material, fatigue criticality, and corrosion requirements.Powder Characterisation TrackerScore a powder batch against key qualification metrics — particle size distribution, flowability, apparent/tap density, moisture, and oxygen content.
Last reviewed: 2026-05-13 · v1 · Sources: haynes-waspaloy-2023, wang-2021-waspaloy-lpbf, tomus-2018-waspaloy-lpbf, debroy-2018-review, sames-2016-metallurgy, yadollahi-2017-fatigue
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