Structure control of a new-type high-Cr superalloy

Abstract

High-Cr superalloys are a new class of nickel-based superalloys with more than 30% Cr, that has greater oxidation resistance than traditional superalloys. This paper compares the α-Cr precipitation behavior in different Cr-containing superalloys. For two tested alloys with more than 37% Cr, α-Cr phase precipitates directly from the austenitic matrix with various morphologies. Heat treatment studies were performed on these two alloys in order to show the precipitation behaviors of α-Cr phase, and find an optimized microstructure distribution. Furthermore, the phenomenon and mechanism of poor hot-working ability for higher alloys are also discussed.