Hot Deformation Behavior, Microstructure Evolution and 3D Processing Map of a Novel Al-Mg-Zn Alloy with Sc and Zr Microalloying
摘要
The hot deformation behavior and microstructure evolution of an Al-Mg-Zn-Sc-Zr alloy under isothermal compression at temperatures ranging from 400 to 475°C and strain rates ranging from 0.001 to 1 s−1 were investigated. Based on the true stress–true strain curves, the flow stress increased with strain, reached a maximum, then decreased and eventually stabilized. An eighth-order strain-compensated Arrhenius model was proposed to predict the flow stress, with an activation energy of Q = 212.54 kJ mol−1, a correlation coefficient of 0.9873 and an average relative error of 5.894%. EBSD analysis indicated that the temperature and strain rate significantly affected the dynamic recrystallization (DRX) behavior of the alloy. The synergistic effect promoted the formation of both continuously and discontinuously recrystallized grains and facilitated the DRX process. Consequently, a large number of fine-sized, low-dislocation and well-oriented DRX grains were generated in the alloy. Based on the hot processing map and microstructural evolution analysis, the optimal hot working parameters for the alloy were determined to be 460-475°C and 0.001-0.005 s−1.