Microstructure and Properties of an Advanced Nickel-base PM Superalloy

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 ℃,was experimentally investigated.Emphasis was primarily put on microstructure and mechanical properties.The results indicated the measured phases in the sample were composed ofγ,γ′,MC,and M3B2.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(R m =1 000 MPa and R p0.2=800MPa at 850℃),strong creep resistance(ξp=0.12%at 815℃/400MPa/50h),and considerable stressrupture life(τ=457.4hat 815 ℃/450 MPa).The technical practicability of applications up to 815-850 ℃ of this alloy was conclusively proved.