Hot deformation behavior and microstructure evolution of WRe alloy under high temperature compression

Abstract

The hot deformation behavior and microstructural evolution of a powder metallurgy W25Re alloy have been investigated by conducting hot compression tests in the temperature range of 1670–1870 K and strain rate range of 0.001–0.1 s⁻¹. Based on the experimental results, a constitutive model with a correlation coefficient of 0.974 was established to predict the yield stresses. Furthermore, a hot processing map was constructed in the temperature range of 1670–1870 K and strain rate range of 0.001–0.1 s⁻¹ to determine the optimum hot processing parameters for the W25Re alloy. In addition, the microstructural evolution of the material was analyzed using electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) techniques. The results indicate that dynamic recovery is the dominant softening mechanism during hot compression. However, the softening effect of dynamic recrystallization becomes more significant with increasing temperature and decreasing strain rate. At deformation temperatures of 1670 K and 1770 K, the alloy exhibited strong 〈100〉// compression direction (CD) and 〈111〉//CD fiber textures. When the deformation temperature is increased to 1870 K, the texture changes from <100>//CD to 〈111〉//CD. The investigation of the thermal deformation mechanism shows that the {123}〈111〉 slip system dominates the thermal deformation process.