GH4105 Alloy

GH4105 is a premium nickel-based precipitation-hardening wrought superalloy, engineered for ultra-high-temperature, high-stress service scenarios demanding exceptional creep rupture strength, microstructural stability, and thermal corrosion resistance. It achieves strengthening primarily through the coherent precipitation of γ’ phase (Ni₃Al, Ti, Nb) — a high-stability strengthening phase — and is supplemented by synergistic solid solution strengthening from chromium (Cr) and molybdenum (Mo). Unlike GH4033 (which relies on Ti-Al γ’ phase), GH4105 incorporates niobium to enhance γ’ phase stability at higher temperatures, enabling reliable long-term operation in harsh environments ranging from 850℃ to 1100℃.

Notably, GH4105 forms a dense, multi-layer oxide film (Al₂O₃-Cr₂O₃-Nb₂O₅) at ultra-high temperatures, providing superior resistance to sulfur-containing flue gas, molten salt, and high-pressure steam corrosion. It retains good hot workability for manufacturing complex load-bearing components (e.g., integral turbine disks) and is widely used in core hot-end parts of next-generation aero-engines, advanced industrial gas turbines, and ultra-supercritical energy equipment, where material performance under extreme thermal-mechanical coupling conditions is critical. The following is a comprehensive breakdown of its chemical composition, physical properties, and application products.

1. Chemical Composition (Mass Fraction, %)

2. Physical Properties

2.1 Basic Physical Parameters

• Density: Approximately 8.30g/cm³ at room temperature (25℃), slightly higher than GH4033 (8.20g/cm³) due to Nb/Mo addition, but 5-7% lower than high-W nickel-based superalloys such as GH3128 (8.70g/cm³). This low-density advantage is critical for weight-sensitive ultra-high-temperature load-bearing components (e.g., aero-engine high-pressure turbine blades), reducing equipment overall weight by 3-8% compared to high-alloyed alternatives like Inconel 718.
• Magnetic Properties: Non-magnetic across the entire service temperature range (room temperature to 1100℃) (magnetic permeability μᵣ ≈ 1.000-1.001). This makes it highly suitable for applications near precision magnetic sensors (e.g., aero-engine turbine speed sensors, nuclear reactor magnetic control systems), as it does not interfere with magnetic field distribution or sensor accuracy.
• Melting Temperature Range: 1350-1410℃ (liquidus: ~1410℃; solidus: ~1350℃). The narrow and stable melting range ensures uniform solidification during investment casting (for turbine blades) and consistent deformation during forging, reducing internal defects (e.g., shrinkage porosity, segregation) and improving structural integrity—critical for high-stress ultra-high-temperature parts like turbine rotors.
• Thermal Expansion Coefficient (CTE):

2.2 Thermal Properties

◦ 20-100℃: ~12.3×10⁻⁶/℃

◦ 20-600℃: ~13.8×10⁻⁶/℃

◦ 20-800℃: ~15.1×10⁻⁶/℃

◦ 20-1000℃: ~15.8×10⁻⁶/℃

◦ 20-1100℃: ~16.1×10⁻⁶/℃

The gradual CTE increase minimizes thermal stress during frequent temperature cycling (e.g., aero-engine start-stop, gas turbine load adjustment), reducing thermal fatigue cracking risk by 50-60% compared to conventional nickel-based alloys (e.g., Inconel 625).

• Thermal Conductivity (λ):

◦ 100℃: ~14.8W/(m·K)

◦ 500℃: ~18.2W/(m·K)

◦ 800℃: ~21.5W/(m·K)

◦ 1000℃: ~23.2W/(m·K)

◦ 1100℃: ~23.9W/(m·K)

The temperature-dependent conductivity improvement promotes efficient heat dissipation in ultra-high-temperature components, avoiding localized overheating (a major cause of γ’ phase coarsening and creep acceleration) and extending part service life by 35-40% compared to GH4033.

2.3 Mechanical Properties (After Standard Heat Treatment: 1100-1140℃ solid solution for 1h, water cooling + 720-750℃ aging for 12h, air cooling)

Key Notes:

• The ultra-high room-temperature strength (σᵦ ≥1000MPa) meets the load-bearing requirements of aero-engine high-pressure turbine blades and ultra-high-pressure fasteners, with strength 5-10% higher than GH4033;
• At 900℃ (a typical service temperature for industrial gas turbine hot-end parts), the creep rupture strength (≥280MPa) is 12-15% higher than that of GH4033, ensuring long-term structural stability under high-temperature cyclic load;
• Even at 1100℃ (near its upper service limit), the retained elongation (≥7%) and creep rupture strength (≥70MPa) prevent brittle fracture during emergency shutdowns, making it suitable for components with extreme thermal cycling (e.g., hypersonic aircraft propulsion system parts).

3. Application Products & Industry Scenarios

3.1 Aerospace Field

As a core material for next-generation aero-engine hot-end parts, GH4105 is used for:

• Aero-engine High-pressure Turbine Blades: Blades (rotational speed up to 20,000 rpm) in large bypass ratio turbofan engines (thrust ≥200kN), operating in 950-1050℃ high-temperature gas environments; the alloy’s creep resistance ensures a service life of up to 40,000 flight hours;
• Integral Turbine Disks: High-pressure integral turbine disks (disk + blade integrated forging), withstanding centrifugal forces up to 45,000g and 900-950℃ gas erosion; its fine-grained structure (grain size 6-9 ASTM) ensures uniform strength distribution;
• Hypersonic Aircraft Propulsion Parts: Heat shield panels and combustion chamber liners in scramjet engines, resisting 1050-1100℃ aerodynamic heating and thermal fatigue, reducing component replacement frequency by 45-55% compared to GH4033.

3.2 Energy Field

3.2.1 Advanced Industrial Gas Turbines

In ultra-high-efficiency industrial gas turbines (turbine inlet temperature: 1300-1400℃) for combined cycle power generation, GH4105 is applied to:

• Turbine Rotor Blades: High-pressure turbine blades (stage 1-3), withstanding 1000-1050℃ high-pressure gas and cyclic thermal stress; the alloy’s creep resistance improves gas turbine efficiency (up to 60% for combined cycle power generation);
• Combustion Chamber Support Structures: Ultra-high-temperature support rings and brackets around combustion chambers, resisting radiant heat and ensuring structural stability for over 120,000 hours of operation.

3.2.2 Ultra-supercritical Nuclear Energy

For advanced nuclear reactors (e.g., molten salt reactors (MSRs) and high-temperature gas-cooled reactors (HTGRs) with coolant temperature: 800-900℃), the alloy is used for:

• Reactor Core Heat Exchanger Tubes: High-temperature heat exchanger tubes in MSRs, resisting corrosion by molten fluoride salts (e.g., LiF-BeF₂) and neutron radiation;
• Reactor Pressure Vessel Liners: Inner liners of HTGR pressure vessels, withstanding 800-850℃ high-temperature helium gas erosion and ensuring reactor safety.

3.3 Petrochemical Field

In large-scale coal-to-olefins and ultra-high-temperature ethylene cracking units (operating temperature: 1000-1100℃), GH4105 is used for:

• Ultra-high-temperature Cracking Furnace Tubes: Core furnace tubes in coal-to-olefins cracking furnaces, resisting hydrocarbon gas pyrolysis corrosion and creep deformation; compared to GH4033, it extends furnace tube service life by 65-75% and reduces maintenance costs by 50-55%;
• High-pressure Syngas Valves: Valve stems and seats in high-temperature syngas pipelines (pressure: 25-30MPa, temperature: 950-1000℃), resisting hydrogen embrittlement and ensuring valve sealing reliability.
• Metallurgical Industry: High-temperature furnace rolls (working temperature: 950-1000℃) for nickel-based superalloy hot rolling, withstanding alloy melt splashing and mechanical wear; its oxidation resistance extends roll service life by 85-95% compared to 310S stainless steel;
• Vacuum Heat Treatment Equipment: Heating elements and furnace liners in ultra-high-temperature vacuum annealing furnaces (operating temperature: 1050-1100℃), ensuring uniform temperature distribution and avoiding contamination of heat-treated workpieces (e.g., high-precision superalloy components);
• High-temperature Test Equipment: Sample holders for ultra-high-temperature creep testing (850-1100℃) and high-load fixture components in material performance testing machines, providing stable support for long-term tests (up to 12,000 hours) and ensuring accurate test data for next-generation superalloy research.
• Hot Working: Forging temperature range: 1140-1200℃; initial forging temperature should not exceed 1200℃ to avoid γ’ phase dissolution and grain coarsening, and final forging temperature should not be lower than 1020℃ to prevent work hardening and cracking;
• Cold Working: Cold working is limited to light deformation (≤12%) such as precision machining and grinding; cold rolling or stamping is not recommended due to ultra-high room-temperature strength; intermediate annealing (1080-1120℃, 1h) is required after any cold deformation to restore ductility;
• Heat Treatment: The two-step process (solid solution + aging) must be strictly controlled—over-aging (above 780℃) will cause γ’ phase coarsening (particle size >0.4μm) and significant strength degradation, while under-aging (below 700℃) will result in insufficient precipitation strengthening and reduced high-temperature creep resistance.

3.4 Metallurgical & High-end Industrial Fields

4. Processing & Heat Treatment Recommendations

This comprehensive performance and application profile makes GH4105 an advanced, high-reliability nickel-based superalloy for ultra-high-temperature high-end manufacturing, perfectly balancing ultra-high-temperature strength, corrosion resistance, and processability for the most demanding hot-end components in aerospace, energy, and petrochemical industries.