Thermal Deformation Behavior and Microstructural Evolution of ZK61M Alloy Plate Fabricated by Asynchronous Cross-Roll Rolling
摘要
To investigate the influence of subsequent processing parameters and the corresponding microstructural evolution, hot compression tests were conducted on asynchronously cross-roll rolled ZK61M magnesium alloy plates. The deformation temperature ranged from 250 to 400 °C and strain rates of 0.001 to 1 s−1. The resulting true stress-strain curves were used to establish and subsequently modify a constitutive equation for the alloy. The microstructural characteristics and recrystallization mechanisms under various hot deformation conditions were systematically analyzed by EBSD. Based on the comprehensive analysis of the flow response and microstructural evolution, the appropriate processing window for a strain range of 0.3 to 0.7 was delineated within 280 to 400 °C and strain rates of 0.001 to 0.01 s−1. Microstructural observations revealed that discontinuous dynamic recrystallization (DDRX) is the dominant mechanism at low temperatures and low strain rates, whereas continuous dynamic recrystallization (CDRX) becomes dominant at high temperatures and high strain rates. Furthermore, hot deformation at high temperature and low strain rate leads to sufficient dynamic recrystallization, resulting in a uniform and refined microstructure.