Effect of initial temperature on dynamic recrystallization of tungsten and matrix within adiabatic shear band of tungsten heavy alloy

Uniaxial dynamic compression tests were performed on tungsten heavy alloys (WHAs) at different temperatures. The microstructure evolution of tungsten grains and matrix within adiabatic shear band (ASB) was investigated. With the initial temperature decreased, the width of elongated subgrain observed in both tungsten grains and matrix shows a decreasing tendency, and the dynamic recrystallization (DRX) process within ASB is evidently suppressed and delayed at cryogenic temperatures. Compared with tungsten grain, the DRX of matrix is earlier and more sufficient, and the observed subgrain of matrix is much finer. No twins were observed during DRX of tungsten grains at various temperatures. However, secondary slip micro bands were observed within the elongated subgrain of matrix at −80 °C, with the angle between the micro bands and original subgrain ranging from 38° to 45°, and twins were observed in matrix at a lower temperature of −140 °C.