The effects of thermomechanical history on the microstructure of a nickel-base superalloy during forging

The effect of thermo-mechanical history on hot compression behaviour and resulting microstructures of a nickel base superalloy is presented. Hot compression tests were carried out on HAYNES® 282® specimens to varying strains from 0.1 to 0.8. Both single pass and multi-pass tests were completed. 60 min inter-pass times were utilized to accurately replicate industrial forging practices. The effect of dynamic, metadynamic and static recrystallization during inter-pass times on flow stress was investigated. The resulting microstructures were analysed using scanning electron, optical microscopy and EBSD to relate grain size and homogeneity with flow stress data. The study showed a negligible difference between multi-pass and single pass tests for strain increments above 0.2. Therefore, when modelling similar low strain and strain rate forging processes in HAYNES® 282®, previous forging steps can be ignored.