Nimonic 105 is a wrought nickel–cobalt–chromium-base alloy strengthened by additions of molybdenum, aluminium and titanium, developed for high-strength, creep-resistant service at temperatures up to 950 °C (1740 °F). This datasheet presents the material within the trade-name designation system.
It combines the high strength of the age-hardening nickel-base alloys with good creep resistance. Cobalt (~20%) and chromium (~15%) provide matrix strength and oxidation resistance; molybdenum gives solid-solution strengthening; and the relatively high aluminium (~4.7%) with titanium forms a substantial gamma-prime [Ni₃(Al,Ti)] phase during aging, providing high tensile and creep-rupture strength. The increased aluminium also improves oxidation resistance relative to earlier Nimonic grades.
It is produced by high-frequency air melting and casting, or — for more critical applications — by vacuum melting and electroslag refining. Typical applications include gas-turbine blades, discs, forgings and ring sections, and high-temperature bolts and fasteners. Strength is developed by a solution treatment followed by aging; the high aluminium-plus-titanium content makes the alloy more challenging to weld than lower-strength Nimonic grades.
Values per Special Metals official datasheet, solution-treated and aged condition.
| Property | Value | Unit |
|---|---|---|
| Density | 7.99 | g/cm³ |
| Melting range | 1290–1345 | °C |
| Young's modulus (20 °C) | 224 | GPa |
| Specific heat capacity (20 °C) | 419 | J/kg·K |
| Thermal conductivity (20 °C) | 10.8 | W/m·K |
| Electrical resistivity (20 °C) | 1.30 | µΩ·m |
| Coefficient of thermal expansion (20–100 °C) | 12.2 | µm/m·°C |
| Maximum creep-resistance temperature | ~950 | °C |
Nominal composition per ASTM C565 (UNS N13021).
| Element | Symbol | Value | Role in Alloy |
|---|---|---|---|
| Nickel | Ni | ~54 (Balance) | Austenitic FCC matrix; γ′-forming base |
| Cobalt | Co | ~20 | Matrix strength; high-temperature stability |
| Chromium | Cr | ~15 | Forms Cr₂O₃ scale; oxidation/corrosion resistance |
| Molybdenum | Mo | ~5 | Solid-solution strengthening |
| Aluminium | Al | ~4.7 | Primary γ′ former; oxidation resistance |
| Titanium | Ti | ~1.3 | γ′ former; strengthening |
| Carbon | C | ~0.13 max | Carbide formation |
| Iron | Fe | ~1.0 max | Residual |
| Manganese | Mn | ~1.0 max | Deoxidiser |
| Silicon | Si | ~1.0 max | Deoxidiser |
| Boron | B | ~0.005 | Grain-boundary strengthening |
| Zirconium | Zr | ~0.10 | Grain-boundary strengthening |
Note: the high combined Al+Ti (~6%) gives a large γ′ volume fraction for high strength, but makes the alloy more difficult to weld.
Typical room-temperature properties, solution-treated and aged condition.
| Property | Value | Source |
|---|---|---|
| Ultimate tensile strength | ~1100–1200 MPa | Special Metals / fully heat-treated |
| 0.2% proof strength (yield) | ~750–830 MPa | Special Metals |
| Elongation at break | ~16–25 % | Special Metals |
| Hardness | ~340–400 HV | Typical |
The high γ′ volume fraction gives excellent tensile and creep-rupture strength retained to ~950 °C. Strength is developed by γ′ precipitation during aging. Values are typical; confirm against the mill test certificate for each delivery.
| Environment | Performance | Notes |
|---|---|---|
| Creep / stress-rupture (to 950 °C) | Outstanding | Co + high-γ′ strengthening; primary selling point |
| High-temperature oxidation | Very Good | Higher Al improves scale stability vs earlier Nimonic |
| High-cycle fatigue | Excellent | High fatigue strength |
| Thermal stability | Excellent | Stable γ′ for long-term high-temperature service |
| Chloride stress-corrosion cracking | Good | High nickel content |
| General corrosion | Good | Ni-Co-Cr base |
A precipitation-hardening alloy. Strength is developed by solution treatment followed by aging.
Solution Treatment Temperature: ~1149 °C (2100 °F), air cool
Aging Temperature: ~1075 °C/4 h/AC + ~850 °C/16 h/AC (typical multi-stage), air cool Purpose: precipitates a high volume fraction of γ′ [Ni₃(Al,Ti)] for maximum tensile and creep-rupture strength.
The high aluminium-plus-titanium content increases susceptibility to strain-age cracking, so heat-treatment and welding sequences must be controlled.
Weldable by GTAW, GMAW, SAW and SMAW, but the high aluminium-plus-titanium content makes the alloy markedly more susceptible to strain-age cracking than lower-strength Nimonic grades. Welding is done in the solution-treated condition, with age-hardening applied afterwards.
| Welding Process | Applicability | Filler / Consumable |
|---|---|---|
| GTAW / TIG · GMAW / MIG | Possible (solution-treated; care needed) | Matching Ni-Co-Cr-Mo filler (solution-treated base) |
| SAW / SMAW | Possible | Matching Ni-Co-Cr electrode |
Use a matching filler metal; if unavailable, a filler rich in Ni-Co-Cr-Mo may be used. Control restraint and pre/post-weld heat treatment to avoid cracking.
Machining Guidelines
| Parameter | Recommendation |
|---|---|
| Preferred condition | Solution-treated (machine before final aging where possible) |
| Tooling | Avoid plain carbon steels (galling risk); use soft die materials + heavy-duty lubricants |
| Work hardening | High rate; rigid setup, positive rake, sharp tooling |
| Coolant | Generous flood coolant |
Forming Processes
| Process | Notes |
|---|---|
| Hot working | High-temperature hot working; ESR/vacuum-melt for critical parts |
| Cold forming | Good ductility; conventional methods + heavy-duty lubricants |
| Final aging | After forming/machining to develop full strength |
| Industry | Typical Components | Key Requirements |
|---|---|---|
| Gas turbines | Turbine blades, discs, forgings, ring sections | High creep-rupture strength to 950 °C |
| Aerospace | Aero-engine hot-section components | High strength + oxidation + fatigue resistance |
| High-temperature fasteners | Bolts and fasteners | High-temperature strength |
| Industrial gas turbines | Hot-section structural parts | Long-term creep strength |
| Product Form | Standard | Notes |
|---|---|---|
| Round bar and extruded section | ASTM C565 | Primary product forms |
| Forgings | ASTM C565-related | Air-melt or VIM/ESR for critical parts |
| Welding consumables | Matching Ni-Co-Cr-Mo filler | — |
Age-hardenable Ni-Co-Cr alloy. UNS N13021; ASTM C565.
| Nimonic Grade | Ni % | Cr % | Other | Best Used For |
|---|---|---|---|---|
| Nimonic 105 | ~54 | ~15 | Co 20, Mo 5, Al 4.7 | Age-hardened Ni-Co-Cr; creep to 950°C |
| Nimonic 90 | bal | 18–21 | Co ~18, Ti+Al | Age-hardened Ni-Cr-Co; to 920°C |
| Nimonic 80A | bal | 18–21 | Ti+Al (no Co) | Age-hardened Ni-Cr; to 815°C |
| Nimonic 115 | bal | ~15 | Co 15, higher Al+Ti | Highest Nimonic strength; to 1010°C |
| Waspaloy | bal | 18–21 | Co 12–15, Mo | Comparable γ′ superalloy; >700°C |




