Neutron diffraction study of Ti-Zr alloy microstructure evolution during annealing after severe plastic deformation

The evolution of the Ti-Zr alloy microstructure (residual stresses, as well as microstress) during annealing after severe plastic deformation is reported. A strong residual macro-stresses relief starts at temperature of 530-540 degrees C. A steep decrease continues up to 580 degrees C and a further slight decrease up to 600 degrees C. Microstrain (caused by the high dislocation density created by equal channel angular pressing) is almost constant up to 300 degrees C, and then begins to decrease gradually due to recovery. The microstrain decrease accelerates at 560 degrees C and is finished at 580 degrees C. Most probably, this is caused by recrystallization. The information obtained is important for possible microstructure modifications and tuning via post-process heat treatment.