Microstructure and Properties of an Advanced Nickel-base PM Superalloy

Abstract

The need for nickel-base powder metallurgy (PM) superalloy turbine discs is becoming increasingly evident. With the eventual aim of improving thrust-to-weight ratio of aeroengines for power generation, well integration of significantly high strength, high damage tolerance and high-temperature capability would be reasonably required. An advanced PM superalloy, which was designed for applications up to 815–850 °C, was experimentally investigated. Emphasis was primarily put on microstructure and mechanical properties. The results indicated the measured phases in the sample were composed of γ, γ′ MC, and M3 B2. With uniform coarse grain microstructure (ASTM 5–6), the sample appeared to exhibit overwhelming superiority over the prior art materials FGH95, FGH96, FGH97 and FGH98. The dominant embodiments consisted of high tensile strength (Rm = 1000 MPa and Rp0.2 = 800 MPa at 850 °C), strong creep resistance (ξ = 0.12% at 8150 °C /400 MPa/50 h), and considerable stress-rupture life (τ = 457.4 h at 815 °C/450 MPa). The technical practicability of applications up) to 815–850 °C of this alloy was conclusively proved.