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采用真空热压-内氧化烧结法制备了TiC(30vol%)/Cu-Al2O3复合材料,测试其基本性能,对其微观组织进行了观察分析。利用Gleeble-1500D热力模拟试验机,在变形温度450~850℃、应变速率0.001~1s-1、变形量50%的条件下,对TiC(30vol%)/Cu-Al2O3进行了热压缩变形试验。通过对流变应力进行分析和计算,构建了该复合材料的本构方程及动态再结晶临界应变模型。利用加工硬化率-应变曲线的拐点和对应偏导曲线最小值的判据,建立了动态再结晶临界应变与Zener-Hollomon参数之间的函数关系。结果表明:TiC(30vol%)/Cu-Al2O3复合材料的真应力-真应变曲线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;计算得出该复合材料的热变形激活能为211.384kJ/mol。
TiC (30vol%) / Cu-Al2O3 composite was prepared by vacuum hot-press internal oxidation sintering method. The basic properties were tested and the microstructure was observed and analyzed. The hot compressive deformation test of TiC (30vol%) / Cu-Al2O3 was carried out with Gleeble-1500D thermomechanical testing machine under the condition of deformation temperature of 450-850 ℃, strain rate of 0.001-1s-1 and deformation of 50%. Through the analysis and calculation of the flow stress, the constitutive equation of the composite material and the critical strain model of dynamic recrystallization are established. The critical strain of dynamic recrystallization and the Zener-Hollomon parameter are established by using the inflection point of the work-hardening-strain curve and the criterion corresponding to the minimum deflection curve. The results show that the true stress-true strain curve of TiC (30vol%) / Cu-Al2O3 composites is characterized by the dynamic recrystallization softening mechanism, and the peak stress increases with the decrease of deformation temperature or strain rate. The thermal deformation activation energy of the composites was 211.384 kJ / mol.