Deformation behavior and microstructural evolution of pure Ti produced by hot compressing
Tianli Zhao, Bing Zhang, Zhijuan Zhang, Le Chen, Yi Xu, Jun Cai, Kuaishe Wang
Abstract
As a component layer of layered composites, pure Ti renders the advantages of high specific strength, low density, low elastic modulus, high-temperature corrosion resistance and excellent biocompatibility. Accordingly, it has broad application prospects in the field of layered composites. In order to study the hot deformation behavior and microstructural evolution of pure Ti during roll bonding processing, hot compression tests were carried out at temperatures of 550–700 °C and strain rates of 0.01–10 s−1 with a true strain of 0.91 on the Gleeble-3500 thermal simulation machine. Arrhenius constitutive model was used to predict the flow behavior of pure Ti, and the correlation coefficient between the experimental and predicted values reached 0.92313. Based on the hot processing maps, it was found that the peak efficiency of power dissipation (η) region occurs at 650–700 °C/0.01–0.02 s−1. At a strain of 0.9, the optimal processing region is found to be 650–680 °C/0.01–0.015 s−1 with the power dissipation value about 0.59–0.62. At high temperature/low strain rate (650 °C/0.01 s−1), the dynamic recrystallization (DRX) phenomenon is obvious in pure Ti. With the increase of strain rate or the decrease of temperature, the discontinuous dynamic recrystallization (DDRX) nucleates at the original grain boundary in the form of grain boundary bow out, and gradually grows by consuming the original deformed grains, forming a typical “necklace” structure.