High-temperature Superalloy Powder Metallurgy Turbine Disc

Core Technology of Superalloy PM Turbine Discs

1. Powder Atomization: Fine spherical alloy powders (10–100 µm) produced via gas atomization with excellent chemical uniformity and low oxygen content.

2. Hot Isostatic Pressing (HIP): Powders consolidated under 100–200 MPa and 1150–1200°C in a HIP furnace, achieving >99.9% density with porosity <0.1%.

3. Isothermal Forging (Optional): Forging at ~1100°C aligns grains and refines microstructure for optimal fatigue and creep strength.

4. Solution and Aging Treatment: Post-forging heat treatment stabilizes γ/γ′ phase, achieving tensile strength up to 1500 MPa.

5. CNC Precision Machining: Multi-axis CNC machining ensures ±0.01 mm dimensional tolerances on all load-bearing and aerodynamic surfaces.

6. Optional Coatings: Surfaces can be finished or coated with oxidation- and thermal-fatigue-resistant layers based on customer specification.

Material Characteristics of PM Superalloys for Turbine Discs

Case Study: Rene 95 Powder Metallurgy Disc for HP Turbine Stage

Project Background

A leading aircraft engine OEM required high-temperature turbine discs for its high-pressure turbine (HPT) stage. Specifications included sustained operation at 700–750°C, fatigue life exceeding 25,000 cycles, and dimensional tolerance under ±0.01 mm. Rene 95 via powder metallurgy was selected for its fatigue strength and microstructural stability.

Typical PM Turbine Disc Applications

• GE CF6 HP Turbine Disc (Rene 95): Used in widebody jet engines, sustaining high-speed rotation and repeated thermal cycling for over 25,000 flight cycles.

• PW4000 Intermediate Turbine Disc (Udimet 720): Offers long-term creep and fatigue reliability in mid-stage aero turbine assemblies.

• GE9X Compressor-Turbine Disc (FGH97): Designed for ultra-high bypass engines with maximum mechanical and thermal loading requirements.

• Siemens Industrial Gas Turbine Disc (FGH97): Supports long-duration base-load power generation with low creep deformation at >700°C.

Manufacturing Solution

1. Powder Selection and Screening: Rene 95 powder screened for optimal particle size distribution and chemistry control.

2. HIP Consolidation: Densified under 1200°C/150 MPa for full consolidation with <0.1% residual porosity.

3. Isothermal Forging: Forged at ~1100°C for uniform grain flow, minimizing stress concentration and improving fatigue resistance.

4. Heat Treatment: Solution annealing at 1150°C followed by dual-stage aging at 760–870°C developed a fine γ′ phase distribution.

5. CNC Machining: Turbine disc bore, face, and dovetail slots machined to ±0.01 mm using advanced 5-axis CNC systems.

6. Quality Assurance: Internal integrity confirmed by X-ray inspection; dimensional accuracy verified by CMM.

Results and Validation

1. Mechanical Strength: Final tensile strength exceeded 1450 MPa; yield strength exceeded 1000 MPa at 700°C.

2. Fatigue Performance: Low- and high-cycle fatigue tests passed 30,000 cycles under simulated engine load profiles.

3. Creep Resistance: 1000-hour creep test at 750°C showed strain under 0.5%, exceeding aerospace turbine spec.

4. Dimensional Tolerances: All critical dimensions confirmed within ±0.01 mm using multi-point CMM verification.

5. Microstructure Quality: SEM and metallography showed uniform γ′ dispersion and absence of pores or cracks.

FAQs

1. Why is powder metallurgy preferred for manufacturing turbine discs in high-temperature engines?

2. How does Rene 95 compare to other superalloys for fatigue and creep performance?

3. What tolerances can Neway AeroTech achieve on machined turbine discs?

4. Are powder metallurgy discs suitable for both aero and industrial turbine applications?

5. What non-destructive tests are used to verify PM disc quality at Neway AeroTech?