Effect of quenching transfer time on microstructure and mechanical properties of oil-quenched FGH4095 superalloys

Abstract

The FGH4095 superalloys prepared by hot isostatic pressing + extrusion + isothermal forging were quenched with the different quenching transfer time, and the microstructure and mechanical properties of the treated superalloys were analyzed. The results show that, the quenching transfer time has little effect on the grain size, primary γ′ phase, and tertiary γ′ phase of the FGH4095 superalloys, but influences the size distribution of the secondary γ′ phase. The average size of the secondary γ′ phase with the quenching transfer time of 30 s is 142.9 nm, and that of the secondary γ′ phase is 161 nm with the quenching transfer time of 40 s. The shorter the quenching transfer time, the faster the quenching cooling rate of the FGH4095 superalloys, and the smaller the average size of the secondary γ′ phase. The yield strength of the FGH4095 superalloys at room temperature with the quenching transfer time of 30 s is better than that of FGH4095 superalloys with quenching transfer time of 40 s, and the tensile strength at room temperature is similar to that of FGH4095 superalloys with quenching transfer time of 40 s. The yield strength, tensile strength, endurance life, and endurance ductility of the FGH4095 alloys with the quenching transfer time of 30 s at 650 ℃ are higher than those of the FGH4095 superalloys with the quenching transfer time of 40 s. The shorter the quenching transfer time, the greater the number of the secondary γ′ phase, the smaller the size, the higher critical shear stress impeding the dislocation movement, the higher the tensile strength and the longer the endurance life of the FGH4095 superalloys.

Keywords

• powder metallurgy superalloys
• quenching transfer time
• microstructure
• tensile strength
• endurance properties