Effect of ultrasonic treatment on the structure of coarse-grained nickel

Abstract Commercially pure coarse-grained nickel was studied. On the electrically polished surface of four samples an area 1 × 1 mm2 in size was marked by a special indenter and studied by EBSD analysis. All the samples were subjected to ultrasonic treatment (UST) with stress amplitudes of 20–80 MPa. The marked area was studied after that. In all the samples, X-ray diffraction analysis, TEM study, microhardness measurements and surface roughness analysis were carried out before and after the UST. It was shown that the UST results in an increase in dislocation density, an increase in the fraction of low-angle boundaries, an increase in microhardness and root-mean-square microstrain. The values of these parameters depend on the UST amplitude.