Markedly enhancing mechanical properties of powder metallurgy superalloy by hot oscillatory forging

A powder metallurgy superalloy prepared by hot pressing (HP) was forged under static and oscillatory pressures. The microstructure, mechanical properties and fracture behavior of the sample before and after forging were characterized in detail. The results showed that the forging processes could effectively break the prior particle boundaries (PPBs) and reduce the PPBs precipitates, thus significantly improved the mechanical properties of the material. In particular, the hot oscillatory forging (HOF) process increased the tensile elongation and stress rapture life of the hot forged sample by 1.3 and 3.5 times, respectively. The present study suggests that HOF could be a promising technique for preparing high-performance superalloys.