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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0.001~1s-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。
In order to determine the dynamic recrystallization behavior of TiC / Cu-Al2O3 composites, this paper provides a theoretical reference for the formulation of thermal processing parameters. The thermal simulations of TiC / Cu-Al2O3 composites were carried out by using Gleeble-1500D thermal simulation machine under the conditions of deformation temperature of 450-850 ℃, strain rate of 0.001-1s-1 and total strain of 0.7. The true stress-strain curves of TiC / Cu-Al2O3 composites were fitted and analyzed, and the work hardening rate was obtained. The critical condition of dynamic recrystallization of the composite was studied by combining the inflection point of the work-hardening-strain curve and the corresponding minimum deflection curve. The results show that the true stress-strain curve of TiC / Cu-Al2O3 composites is mainly characterized by the dynamic recrystallization softening mechanism, and the peak stress increases with the decrease of deformation temperature or strain rate. The work hardening rate-strain The inflexion point of the curve appears, corresponding to the minimum value of the partial derivative curve. The critical strain decreases with the increase of the deformation temperature and the strain rate, and the correlation between the critical strain and the peak strain and the Zener-Hollomon parameter.