Effect of Ultrasonic Treatment on the Structure and Properties of Ultrafine-Grained Nickel

Effect of ultrasonic treatment on the microstructure, microhardness, and thermal stability of nickel subjected to high-pressure torsion (under a quasi-hydrostatic pressure of 6 GPa) has been studied. It has been demonstrated that ultrasound favors a considerable decrease in internal microstresses. It has been found that after an ultrasonic treatment, the grain growth proceeds at higher annealing temperatures than it does in ultrafine-grained nickel that has not been subjected to ultrasonic treatment.