Thermal stability of the HPT-processed tungsten at 1250 – 1350 °C

Abstract Unveiling the influence of the high-pressure torsion (HPT) on microstructure for pure tungsten under annealing process is of great significance to realize the control of thermal stability and irradiation resistance at high temperatures. To this end, a detailed investigation on the microstructure evolution, energy release and its hardness change is conducted. The results show that the microstructure with homogeneous fine grains and the favorable orientation with high irradiation resistance appeared after the continuous static recrystallization (cSRX). During the HPT and subsequent annealing process, the stored energy change is mainly affected by high angle grain boundaries (HAGBs). Although the ultrahigh stored energy released in the annealing process, the homogeneous fine grains and the boundaries with high average misorientation lead to the stable grain growth with the low boundary velocity even at high temperatures and then improve the irradiation resistance of tungsten. And the high hardness retention is also presented at 1350 °C. Results reveal that, performing HPT makes it possible to improve the thermal stability and irradiation resistance in pure tungsten.