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在变形温度为1223~1423 K及应变速率为0.01~10 s-1的条件下,利用MMS-300热模拟试验机开展单道次压缩变形实验,结合SEM-EBSD和TEM等观察分析技术,研究了一种高锰奥氏体孪晶诱发塑性(TWIP)钢的高温热变形及再结晶行为,对其动态再结晶过程中的组织演变规律及其与应力-应变曲线的相关性进行了分析和表征.结果表明,该高锰奥氏体TWIP钢的热变形行为对应变速率较敏感;当应变速率低于0.1 s-1时,热变形过程中发生动态再结晶;当应变速率高于1 s-1时,发生动态回复.通过回归计算建立了该高锰奥氏体TWIP钢的热变形本构方程,分析认为动态再结晶过程中的组织演变规律与其应力-应变曲线密切相关.随着应变量的增加,晶界迁移诱导再结晶形核;形变量进一步增加,产生大量亚晶界;相邻亚晶界上的位错攀移和滑移等运动使晶界合并,导致再结晶晶粒形成.
Under the conditions of deformation temperature of 1223 ~ 1423 K and strain rate of 0.01 ~ 10 s-1, single-pass compression deformation test was carried out by MMS-300 thermal simulation test machine, combined with SEM-EBSD and TEM observation and analysis techniques A high temperature hot deformation and recrystallization behavior of high manganese austenite twin induced plasticity (TWIP) steel was studied. The microstructure evolution regularity and its relationship with stress-strain curve during dynamic recrystallization were analyzed. The results show that the hot deformation behavior of the high manganese austenite TWIP steel is sensitive to the strain rate. When the strain rate is lower than 0.1 s-1, dynamic recrystallization occurs during the hot deformation. When the strain rate is higher than 1 s -1, the dynamic response occurs.The thermal deformation constitutive equation of the high manganese austenitic TWIP steel is established by regression analysis, and the results show that the regularity of microstructure evolution during dynamic recrystallization is closely related to the stress-strain curve With the increase of the variables, the grain boundary migration induces recrystallization nucleation; the amount of deformation increases further to produce a large number of subgrain boundaries; the movement of dislocation climbs and slippages on the adjacent subgrain boundaries merges the grain boundaries, resulting in recrystallized grains form.