Conjoint Influence of Heat Treatment, Hot Deformation and Cold Working on the Microstructure and Mechanical Response of a Co-Based Superalloy

An as-cast HAYNES 25 Co-based superalloy is subjected to a process, including four stages of heat treatment, hot deformation, cold working, and aging. Mechanical properties have been improved after processing; the hardness, tensile and yield strengths are enhanced while the reduction of ductility is reasonable. The process has led to break down the segregated as-cast microstructure and has given a well distributed inter-metallic reinforced microstructure with no segregation. The grain structure also includes the approximately equiaxed grains with a large density of Σ3 twins. The results showed that as the hot deformation plays an important role in the grain refinement and microstructure homogenization, it should be considered as an important phase of the manufacturing process.