Hot deformation behaviour and optimization of process parameters for an as-cast Cu–20Ni–20Mn alloy

Abstract

The hot deformation behaviour of an as-cast Cu–20Ni–20Mn alloy was investigated by isothermal compression tests in a TA-DIL 805 phase change thermal expansion instrument with a temperature ranging from 800 to 950 °C and a strain-rate ranging from 0.001 s−1 to 1 s−1. The results showed that Cu–20Ni–20Mn presented a stress drop at the beginning of the strain, and the flow stress decreased with increasing temperature and decreasing of strain rate. In particular, the hot deformation activation energy was determined to be 277.958 kJ/mol. The hot compression constitutive equation was established, and the processing maps of the alloy were constructed. The stress-strain values predicted by the proposed model were coincident with the experimental results, which confirmed that the deformation principal equation gives an accurate and precise estimate of the flow stress in Cu–20Ni–20Mn. The established processing maps and microstructure analysis determined the rolling process parameters in which the optimum range of temperature for the hot-working deformation of the as-cast Cu–20Ni–20Mn alloy is 810–900 °C with a strain rate of 0.001–0.002 s−1.