LAUSR

Abstract Hot deformation behavior and processing maps of Ni45Ti50Cu5 (at.%) shape memory alloy (SMA), which possesses acicular martensite phase at room temperature, were investigated systematically based on isothermal compression tests at the temperatures ranging from 600 to 1000 °C and the strain rates ranging from 0.0005 to 0.5 s−1. The flow stresses of the studied alloy were found to be dependent on the strain rate as well as the temperature. Processing maps at strains of 0.3, 0.6 and 0.9 were constructed on the basis of dynamic material model (DMM) theory by using the flow stresses obtained from compression tests. According to the processing maps, flow instability was found to mainly occur in the region with high strain rate and the scope of instability region was found to increase with the increase in the true strain. Based on the combination of processing map and microstructural observations, microstructural defects were found in the alloy samples deformed in the instability regions and the parameters suitable for hot working of the studied alloy were determined as the temperatures ranging from 750 to 850 °C and the strain rates ranging from 0.0005 to 0.001s−1.