Effect of slow cooling treatment on hot deformation behavior of GH4742 superalloy

The very poor hot workability of high-alloyed GH4742 superalloy is represented in the aspects of very narrow available deformation temperature range, high deformation-resistant force and poor ductility. In this paper, a special heat treatment to change the ingot microstructure is proposed to improve the hot workability of the GH4742 superalloy. The γ′ phase with an appropriate size and morphology and tortuous grain boundary were obtained by slow cooling in the γ + γ′ two phases region after solution treatment. Modified microstructure induces that the hot deformation flow stress of GH4742 superalloy was decreased effectively and hot deformation plasticity was increased obviously.