Discontinuous yielding behavior and microstructure evolution during hot deformation of TC11 alloy

Discontinuous yielding behavior of TC11 alloy was found during hot compression tests at temperatures of 1000-1050 degrees C and the strain rate of 10 s(-1). The flow stress showed a rapid drop and subsequent oscillation after peak stress before true strain of 0.15. It was proved to be the result of the stress induced phase transformation (alpha ->beta), which introduced softening effect for the generation of new beta phase. Moreover, the magnitude of the stress drop increased with the increasing of the fraction of stress induced phase transformation. In addition, these newly generated beta phase were further deformed by subsequent compression strain. As a result, the phase transformation of beta ->alpha '' was found in final quenched microstructures.