Study on High-Temperature Deformation Behavior of Homogenized Industrial Electrolytic Nickel

Hot compression experiments were carried out on homogenized industrial electrolytic nickel by a Gleeble-3 500 thermal simulation tester, and the high temperature deformation behavior was investigated at the temperature of 900, 1000, 1100, and 1200 degrees C under the strain rate of 0.01, 0.1, 1, and 10 s(-1) and the deformation of 60%. The microstructure evolution of electrolytic nickel during hot deformation was investigated by EBSD. The true stress-true strain curves were obtained based on the compression data, the effects of deformation temperature and strain rate on the mechanical properties of electrolytic nickel were analyzed, the rheological stress eigenstructure equations were obtained, and the thermal processing diagrams were established based on the dynamic material model and the Prassd instability criterion. The results show that electrolytic nickel exhibits strong sensitivity to deformation temperature and strain rate, and the rheological stress decreases gradually with the increase of deformation temperature and the decrease of strain rate. With the increase of strain, the rheological stress reaches a peak, decreases to a certain value, and then tends to stabilize, showing the characteristics of rheological softening. Discontinuous dynamic recrystallization of electrolytic nickel occurs during hot deformation, and the dynamic recrystallization process occurs more completely at low strain rates as the deformation temperature increases with the transformation of small-angle grain boundaries to large-angle grain boundaries. According to the thermal processing diagram, the better thermal processing process range of electrolytic nickel is obtained as follows: the range of deformation temperature is 980-1040 degrees C and the change of strain rate is from 3.16 s(-1 )to 10 s(-1); the deformation temperature is 1100 degrees C and the strain rate is from 1 s(-1) to 4 s(-1).