TiC/CuAl2O3复合材料动态再结晶临界条件

为了确定TiC/Cu-Al₂O₃复合材料的动态再结晶行为，为热加工工艺参数的制定提供理论参考。采用Gleeble-1500D热模拟试验机，在变形温度450~850℃、应变速率0.001~1 s^-1、总应变量为0.7的条件下，对TiC/Cu-Al₂O₃复合材料进行热模拟试验。对TiC/Cu-Al₂O₃复合材料的真应力-应变曲线数据进行拟合、分析，求得材料的加工硬化率。结合加工硬化率-应变曲线的拐点和对应偏导曲线最小值的判据，研究了该复合材料动态再结晶临界条件。结果表明：TiC/Cu-Al₂O₃复合材料的真应力-应变曲线主要以动态再结晶软化机制为特征，峰值应力随变形温度的降低或应变速率的升高而增加；该材料的加工硬化率-应变曲线出现拐点，对应偏导曲线出现最小值；临界应变随变形温度的升高与应变速率的降低而减小，且临界应变与峰值应变以及Zener-Hollomon参数之间具有相关性。

Critical conditions of dynamic recrystallization of TiC/Cu Al2O3 composites

In order to determine the dynamic recrystallization behavior of TiC/Cu-Al₂O₃ composites and provide theoretical reference for the development of hot working process parameters. Using the Gleeble-1500D simulator, the hot simulation compression tests of TiC/Cu-Al₂O₃ composites were conducted at deformation temperature of 450-850℃, the strain rate of 0.001-1 s^-1 and total strain of 0.7. The true stress-strain curves of TiC/Cu-Al₂O₃ composites were fitted and analyzed. The work hardening rate of TiC/Cu-Al₂O₃ composites was obtained. The critical conditions of dynamic recrystallization were studied by the inflection point criterion of work hardening rate-strain curves and the minimum value criterion of corresponding partial derivative curves. The results indicate that the softening mechanism of the dynamic recrystallization is a feature of true stress-strain curves of the composites, and the peak stress increases with the decrease of deformation temperature or the increase of strain rate. The inflection point in the work hanrdening rate-strain curve appears and the minimum value of the corresponding partial derivative curve is presented when the critical state is attained for this composite. The critical strain decreases with the increasing deformation temperature and the decreasing strain rate. There is linear relationship between critical stra in, peak strain and Zener-Hollomon parameter.