Influence of ultrasound on the structure and properties of nickel processed by equal-channel angular pressing

Commercially pure nickel was processed by equal-channel angular pressing (ECAP) and subjected to ultrasonic treatment (UST) with a stress amplitude of 100 MPa. The microstructure, microhardness and mechanical properties of the deformed and sonicated samples were studied. It was shown that the UST affected the microstructure of ECAP nickel. A refinement of grains in the longitudinal section, changes in the texture, and an increase in the dislocation density and microstrain were observed. Tensile tests have shown an increase in the elongation to failure without any noticeable changes in the tensile strength. The possible mechanisms of the action of ultrasound on the structure and properties of the deformed nickel are discussed.