Work-hardening behaviors of typical solution-treated and aged Ni-based superalloys during hot deformation

A detailed analysis of work-hardening behavior is useful to optimize the hot forming processing of metals or alloys. The hot compression tests of solution-treated and aged Ni-based superalloys are carried out over wide ranges of temperature and strain rate. Based on the experimental data, the effects of strain rate, deformation temperature, strain and δ phase (Ni3Nb) on the work-hardening behaviors are discussed in detail. The microstructures of the studied superalloy are observed to correlate with the complex dynamic deformation mechanisms. The experimental results show that the work-hardening behaviors of the studied superalloy are significantly affected by deformation temperature, strain rate, strain and δ phase. The work-hardening rate increases with the decrease of deformation temperature or the increase of strain rate. When the deformation degree is relatively small, δ phase can inhibit the dislocation movement and enhance the work-hardening behavior. However, with further straining, δ phase stimulates the occurrence of dynamic recrystallization and promotes the dynamic softening. When the deformation temperature is higher than the dissolution temperature of δ phase, the effects of δ phase on work-hardening behaviors are weakened.