The investigation of microstructure evolution, deformation behavior and processing performance of the high niobium containing TiAl alloys

Phase transformation and crystal structure variety will influence microstructure evolution and deformation behavior of high niobium containing TiAl alloys. The deformation mechanisms and the processing maps of Ti–43Al–6Nb–1Mo–1Cr alloys have been studied in this paper. The nucleation and growth of recrystallized γ and α grains can dominate the deformation below or above Tα2→α, respectively, in the temperature range of 1100°C-1200 °C. Additionally, the dynamic recovery (DRV) of α phase dominates the deformation in the condition with low strain rates above 1200 °C. In combination with the microstructure observation, the processing maps by Prasad and Murty instability criterion indicates that the suitable processing region with dynamic recrystallization (DRX) is about in the temperature range of 1100°C-1200 °C and the strain rate range of 0.01s−1-0.001s−1. Summarily, various deformation mechanisms have been discussed and the deformation mechanism map has been obtained, based on different types of microstructure analysis.