Hangbo Alloy Group
Shanghai · Est. 2012
UNS N07112 — Nickel-cobalt-chromium precipitation-hardened superalloy with high gamma prime volume fraction, outstanding creep-rupture strength at 800–900 °C, and gas turbine blade and disc applications.
Nimonic 105 (UNS N07112) is a high-performance nickel-cobalt-chromium precipitation-hardened superalloy developed by Special Metals Corporation (originally Henry Wiggin & Company) for gas turbine blade and disc applications operating at temperatures up to 900 °C. It belongs to the Nimonic family of alloys, which were among the first purpose-designed superalloys for the British jet engine industry in the 1940s–1960s, and Nimonic 105 represents the highest-strength forged variant in the series.
The defining feature of Nimonic 105 is its exceptionally high combined aluminum-plus-titanium content (~9%), which produces a gamma prime (Ni3(Al,Ti)) volume fraction of approximately 45% after the full four-step heat treatment. This is significantly higher than Nimonic 80A (~30%), Nimonic 90 (~30%), or Inconel 718 (~30%), and it is the principal source of the alloy’s outstanding creep-rupture strength at temperatures where the gamma prime phase is still stable. Cobalt (~15%) provides additional solid-solution strengthening and stabilizes the gamma prime phase against dissolution at elevated temperature, while chromium (~15%) provides oxidation resistance and molybdenum (~5%) adds further solid-solution strength.
Nimonic 105 was developed as an evolution of Nimonic 90, with aluminum raised from ~2% to ~5% and titanium from ~2.5% to ~4%, plus molybdenum added at ~5%. These changes doubled the gamma prime volume fraction and dramatically improved creep-rupture life at 800–900 °C, making Nimonic 105 suitable for the highest-stress, highest-temperature forged blade and disc positions in both aero and industrial gas turbines. The trade-off was significantly reduced weldability and a more complex heat treatment sequence.
At Hangbo Alloy Group, Nimonic 105 is melted by vacuum induction melting (VIM) followed by vacuum arc remelting (VAR) for the cleanest possible ingot structure, then forged and solution-treated. Each lot is tested for chemical composition, grain structure (ASTM grain size 3–5 for creep-optimized forging), tensile properties, and creep-rupture life per OEM specifications.
The composition of Nimonic 105 is optimized for maximum gamma prime volume fraction while maintaining sufficient chromium for oxidation resistance and cobalt for gamma prime stability. The combined Al+Ti content of ~9% is the highest among the commonly forged Nimonic alloys and is the principal driver of the alloy’s exceptional creep-rupture strength. The carbon and boron additions provide grain-boundary strengthening through carbide and boride precipitation, while zirconium helps control grain-boundary morphology during long-term creep exposure.
| Element | Min % | Max % |
|---|---|---|
| Nickel (Ni) | Balance (~53) | Balance |
| Cobalt (Co) | 14.0 | 17.0 |
| Chromium (Cr) | 14.5 | 15.5 |
| Aluminum (Al) | 4.5 | 5.0 |
| Titanium (Ti) | 3.7 | 4.2 |
| Molybdenum (Mo) | 4.5 | 5.0 |
| Carbon (C) | 0.12 | 0.17 |
| Boron (B) | 0.003 | 0.008 |
| Zirconium (Zr) | 0.05 | 0.15 |
| Iron (Fe) | — | 1.0 |
| Manganese (Mn) | — | 0.25 |
| Silicon (Si) | — | 0.25 |
| Sulfur (S) | — | 0.015 |
| Lead (Pb) | — | 0.005 |
| Silver (Ag) | — | 0.0005 |
| Bismuth (Bi) | — | 0.0001 |
Nimonic 105 has an austenitic (FCC) matrix structure at all service temperatures, with approximately 45% of the volume occupied by gamma prime (Ni3(Al,Ti)) precipitate particles after the full heat treatment. The gamma prime particles are coherent with the matrix and provide the primary strengthening mechanism. Their size and distribution are controlled by the four-step heat treatment: the first aging at 1065 °C precipitates the primary coarse gamma prime, while subsequent lower-temperature aging steps precipitate finer secondary gamma prime particles between the coarse ones, creating a dual-size distribution that maximizes both short-time strength and long-time creep resistance.
| Property | Value | Unit |
|---|---|---|
| Density | 8.01 | g/cm³ |
| Melting Range | 1315–1370 | °C |
| Specific Heat (20–100 °C) | ~450 | J/kg·K |
| Thermal Conductivity (20 °C) | ~11.5 | W/m·K |
| Electrical Resistivity (20 °C) | ~1.19 | μΩ·m |
| Modulus of Elasticity (20 °C) | ~225 | GPa |
| Mean CTE (20–100 °C) | ~11.5 | × 10−6/°C |
| Mean CTE (20–500 °C) | ~13.0 | × 10−6/°C |
| Mean CTE (20–800 °C) | ~14.5 | × 10−6/°C |
| Mean CTE (20–900 °C) | ~15.5 | × 10−6/°C |
Nimonic 105 achieves its mechanical properties through the full four-step heat treatment, which produces the optimal dual-size gamma prime distribution and a controlled grain size (typically ASTM 3–5 for creep-optimized material). Room-temperature strength is very high due to the ~45% gamma prime volume fraction, but the alloy’s primary value lies in its elevated-temperature strength and creep-rupture performance, which far exceed those of Nimonic 80A, Nimonic 90, or Inconel 718 at temperatures above 800 °C.
| Property | Solution Treated | Fully Aged (4-step) |
|---|---|---|
| Tensile Strength | ~700 MPa (102 ksi) | 1100–1200 MPa (160–175 ksi) |
| Yield Strength (0.2%) | ~350 MPa (51 ksi) | 750–850 MPa (110–125 ksi) |
| Elongation (in 50 mm) | ~40% | 10–15% |
| Hardness | ~25 HRC | 36–40 HRC |
| Reduction of Area | ~50% | 12–18% |
The high-temperature strength of Nimonic 105 is its defining engineering advantage. At 800 °C, tensile strength remains above 600 MPa, and the creep-rupture life at 800–870 °C under moderate stress (150–200 MPa) exceeds that of all earlier Nimonic alloys by a substantial margin. This is directly attributable to the high gamma prime volume fraction, which remains stable at these temperatures and resists dislocation climb and creep deformation.
Nimonic 105 also has good fatigue resistance at elevated temperature, particularly in the low-cycle fatigue regime relevant to turbine disc applications where cyclic thermal and centrifugal stresses combine. The controlled grain size (ASTM 3–5) and dual-size gamma prime distribution provide a balance between creep resistance (favoring coarser grains) and fatigue resistance (favoring finer grains).
| Temperature (°C) | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) |
|---|---|---|---|
| 20 (RT) | 1100–1200 | 750–850 | 10–15 |
| 600 | 950–1050 | 650–750 | 12–18 |
| 700 | 800–900 | 500–600 | 15–20 |
| 800 | 600–700 | 350–450 | 18–25 |
| 870 | 450–550 | 250–350 | 20–30 |
| 900 | 350–450 | 180–280 | 25–35 |
| Temperature (°C) | Stress (MPa) | Rupture Life (hours) |
|---|---|---|
| 800 | 350 | ~50 |
| 800 | 250 | ~300 |
| 800 | 150 | >1000 |
| 870 | 250 | ~30 |
| 870 | 150 | ~200 |
| 870 | 100 | >500 |
| 900 | 150 | ~25 |
| 900 | 100 | ~100 |
Nimonic 105 has good oxidation resistance at elevated temperature due to its 15% chromium content, which forms a Cr2O3 protective oxide scale. The addition of 5% aluminum further enhances oxidation resistance by forming an Al2O3 sub-scale beneath the chromium oxide. This dual-oxide system provides reasonably good protection up to 900 °C in clean combustion gas atmospheres.
However, Nimonic 105 is not a corrosion-resistant alloy in the sense of Hastelloy or Inconel 625. It is designed for high-temperature structural service in relatively clean gas turbine environments, not for chemical processing or seawater exposure.
Nimonic 105 requires a four-step heat treatment sequence that is more complex than most other superalloys. This sequence is designed to produce the optimal dual-size gamma prime distribution and grain structure for maximum creep-rupture strength. Simplifying the heat treatment by combining or eliminating steps will reduce both short-time and long-time high-temperature properties.
The 16-hour hold times at each aging step are essential for complete precipitation and uniform distribution. Shorter holds will under-age the alloy and reduce both tensile strength and creep-rupture life. The total heat treatment cycle requires approximately 80–90 hours (4+16+16+16 hours plus heating and cooling transitions), making it one of the longest and most expensive heat treatment sequences in the superalloy industry.
Nimonic 105 is used almost exclusively in gas turbine and aerospace applications where its combination of high gamma prime volume fraction, excellent creep-rupture strength at 800–900 °C, and good oxidation resistance makes it the optimal forged superalloy choice. It was historically a key material in British-designed gas turbines and remains in service in both aero and industrial engines worldwide.
Hangbo Alloy Group supplies Nimonic 105 in the following forms, all VIM+VAR melted and solution-treated for customer-side aging:
| Standard | Description |
|---|---|
| MSRR 7012 | Rolls-Royce Material Specification for Nimonic 105 Bar |
| MSRR 7013 | Rolls-Royce Specification for Nimonic 105 Forgings |
| MSRR 7014 | Rolls-Royce Specification for Nimonic 105 Sheet |
| BS HR3 | British Standard for Nimonic 105 |
| GE Spec (various) | GE Aviation Specifications for Nimonic 105 Components |
| SAE AMS 2269 | Chemical Check Analysis Limits for Nickel Alloys |
Nimonic 105 (UNS N07112) is a nickel-cobalt-chromium precipitation-hardened superalloy with ~9% combined Al+Ti, producing ~45% gamma prime volume fraction and outstanding creep-rupture strength at 800–900 °C. It was developed for gas turbine blade and disc applications and is the highest-strength forged alloy in the Nimonic family.
Ni balance (~53%), Co 14–17%, Cr 14.5–15.5%, Al 4.5–5.0%, Ti 3.7–4.2%, Mo 4.5–5.0%, C 0.12–0.17%, B 0.003–0.008%, Zr 0.05–0.15%, Fe ≤1.0%. The high Al+Ti content (~9%) drives the large gamma prime fraction.
Density is 8.01 g/cm³. Melting range is 1315–1370 °C. Gamma prime volume fraction is ~45% after full heat treatment. Grain size is typically ASTM 3–5 for creep-optimized forging.
Nimonic 105 is covered by Rolls-Royce MSRR 7012 (bar), 7013 (forging), 7014 (sheet), British Standard BS HR3, and various GE Aviation specifications. There is no direct ASTM specification; it is typically ordered per OEM proprietary specs.
After the four-step heat treatment, Nimonic 105 achieves RT tensile strength of 1100–1200 MPa and yield strength of 750–850 MPa, with elongation 10–15%. At 800 °C, tensile strength remains above 600 MPa.
Nimonic 105 has significantly higher creep-rupture strength at 800–900 °C due to ~45% gamma prime (vs ~30% in Nimonic 90). Key composition differences: Al 5% vs 2%, Ti 4% vs 2.5%, Mo 5% vs 0%. Nimonic 105 also has higher cobalt (15% vs 20% in Nimonic 90). Nimonic 90 is better for applications below 800 °C where weldability is needed.
Nimonic 105 is designed for service up to 900 °C for short-duration peak conditions and 870 °C for long-term continuous creep-rupture service. Above 950 °C, gamma prime dissolution and oxidation become limiting. Coating (aluminide or MCrAlY) extends the oxidation-safe limit.
Four-step: (1) Solution at 1150 °C for 4 hrs, air cool; (2) 1065 °C for 16 hrs, air cool; (3) 980 °C for 16 hrs, air cool; (4) 795 °C for 16 hrs, air cool. Total cycle ~80–90 hrs. This produces dual-size gamma prime distribution maximizing creep-rupture strength. Simplifying the sequence will reduce properties.
Extremely difficult to weld due to ~9% Al+Ti promoting strain-age cracking in the HAZ. Fusion welding is generally not recommended. When required, weld in solution-treated condition with minimal heat input (GTAW, near-matching filler), then full four-step heat treat. Resistance and EB welding preferred for limited applications.
HP and IP turbine blades, turbine discs, shafts, aerospace fasteners for 600–800 °C service, industrial gas turbine hot-section forged components. Historically used in Rolls-Royce Spey, Dart, and Tyne engines.
Round bar: USD 60–120/kg FOB Shanghai (2026). Forgings: USD 80–150/kg equivalent. Minimum orders 50–100 kg for bar. Lead time 6–10 weeks due to specialty melting and multi-step heat treatment.
Round bar 6–200 mm (solution-treated), forging stock and custom forgings per drawing, billets 150–350 mm, limited wire 0.5–5.0 mm, and limited sheet/plate up to 20 mm.
Hangbo Alloy Group provides mill-direct supply of Nimonic 105 bar, forging, billet, and wire to gas turbine manufacturers and aerospace OEMs worldwide. Our material is VIM+VAR melted, solution-treated, and fully certified per Rolls-Royce MSRR, GE, and customer OEM specifications. We can assist with grain size optimization for your specific creep-rupture requirements, heat treatment consulting, coating specification, and export documentation for aerospace-grade shipments.
For quotations, material certifications, or technical consultation, contact our sales team or call +86-136-1165-6360. We typically respond within 10 minutes.
Request a quotation for Nimonic 105 bar, forging, or billet with OEM-spec certification. VIM+VAR melting, Rolls-Royce MSRR compliance, and creep-rupture testing available.