【摘要】 为了研究热变形过程中动态再结晶对金属流变行为的影响,采用Gleeble-3800热模拟机对CuCrZr合金和35CrMo钢进行了高温压缩实验。通过观察热变形后样品的金相组织,证明了样品在热变形过程中经历了明显的动态再结晶,且动态再结晶晶粒尺寸随着变形温度的升高和应变速率的降低而增大。以应力-位错密度的关系为理论依据,定义了由动态再结晶所引起的净软化作用η。η与Z参数之间呈三次递减关系。计算得到的CuCrZr合金和35CrMo钢的最大η值分别为21.9%和29.8%。基于所提出的动态再结晶软化效应,构建了两种合金的高温流动行为本构模型。并对模型参数进行了定义和求解。所建模型的预测值与实验所得的数据高度吻合。更多还原

【Abstract】 In order to study the effect of dynamic recrystallization on the metal flow behavior during thermal deformation, the elevated temperature compression experiments of CuCrZr alloy and 35 CrMo steel are carried out using Gleeble-3810 thermal simulator. It is proved that the samples underwent obvious dynamic recrystallization behavior during thermal deformation by microstructure observation of deformed specimens. The size of recrystallized grains increases as the temperature improved and the strain rate decreased. Meanwhile, the net softening rate caused by dynamic recrystallization is determined based on the stress-dislocation relationship. It can be found that the value of net softening rate increases quadratically as the Z parameter decreases, and the dynamic recrystallization net softening rate of Cu Cr Zr alloy and 35 Cr Mo steel are calculated to be 21.9% and 29.8%, respectively. Based on the dynamic recrystallization softening effect proposed, the novel elevated temperature flow constitutive models of two different alloys are proposed, and the related parameters are well defined and solved in detail. The predicted values of the obtained models are agreed well with the experimental values.更多还原