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 delta 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 delta 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, delta phase can inhibit the dislocation movement and enhance the work-hardening behavior. However, with further straining, delta phase stimulates the occurrence of dynamic recrystallization and promotes the dynamic softening. When the deformation temperature is higher than the dissolution temperature of delta phase, the effects of delta phase on work-hardening behaviors are weakened. (C) 2014 Elsevier B.V. All rights reserved.