Thermal deformation behavior and microstructure evolution of Mo–14Re alloys prepared by powder metallurgy

The constant strain rate compression experiment of powder metallurgy Mo–14Re alloys was carried out by Gleeble 1500 thermal simulation tester. The effects of deformation temperature (1100~1400 ℃) and strain rate (0.100~0.001 s⁻¹) on the flow stress and microstructure evolution were analyzed. The constitutive equation of Mo–14Re alloys was established by hyperbolic sinusoidal Arrhenius model. The results show that, the flow stress of powder metallurgy Mo–14Re alloys decreases with the increase of deformation temperature or the decrease of strain rate during the thermal deformation, and the true stress-true strain curve shows the obvious work hardening and dynamic softening phenomenon. The dynamic softening behavior is mainly attributed to the dynamic recrystallization of Mo–14Re alloys at low strain rate (0.010 s⁻¹ and 0.001 s⁻¹) or high deformation temperature (>1200 ℃) during the thermal compression. The nucleation mode is grain boundary protruding nucleation. With the decrease of strain rate or the increase of temperature, the degree of recrystallization continues to increase, the grains continue to grow, and the Mo–14Re alloys are completely recrystallized at 1400 ℃ with the strain rate of 0.001 s⁻¹.