Structure and strain hardening of superalloy AEREX350

Mechanical testing and microscopy techniques were used to characterize the strain-hardening behavior and microstructural evolution of the newly developed AEREX350 superalloy during large strain simple compression deformation. The alloy in solution-treated condition showed a four-stage hardening response similar to that reported in earlier studies of low SFE alloys. TEM investigations on solution-treated samples deformed to various strain levels revealed the existence of deformation twins at strains larger than about 0.10 in simple compression. Also, TEM studies on aged samples showed that the major strengthening phase formed in the temperature range 700–1000°C was coherent γ′ with L12 structure. The strain-hardening rate of the precipitation hardened alloy showed a significant increase in the strain range 0.08–0.30 compared to that of solution-treated alloy while, at larger strains, the strain-hardening responses of the two were rather similar. The physical origin of this behavior is still under investigation.