A study on hot deformation behavior of Ni-42.5Ti-7.5Cu alloy

To investigate the hot deformation behavior of the Ni-42.5Ti-7.5Cu (wt%) alloy, hot compression tests were carried out at the temperatures from 800 degrees C to 1000 degrees C and at the strain rates of 0.001 s(-1) to 1 s(-1). The results show that the occurrence of dynamic recrystallization (DRX) is the dominate restoration mechanism during the hot deformation of this alloy. There is an increase in peak and steady state stresses with decreasing the deformation temperature and increasing the strain rate. The experimental results were then used to determine the constants of developed constitutive equations. There is a good agreement between the measured and predicted results indicating a high accuracy of developed model. Zener-Hollomon (Z) parameter, calculated based on the developed model, indicates that DRX was postponed when the logarithm of the Zener-Hollomon parameter fell around 33 at strain rate of 0.001 s(-1) and temperature of 900 degrees C. This phenomenon can be regarded as the interactions between solute atoms and mobile dislocations. The established constitutive equations can be used to predict and analyze the hot deformation behavior of Ni-42.5Ti-7.5Cu alloy. (C) 2013 Elsevier B.V. All rights reserved.