Hot deformation and dynamic recrystallization of TiC(30vol%)/Cu-Al2O3 composites
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摘要: 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0.001~1 s-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211.384 kJ/mol。
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关键词:
- TiC(30vol%)/Cu-Al2O3 /
- 复合材料 /
- 热变形 /
- 本构方程 /
- 动态再结晶
Abstract: The TiC(30vol%)/Cu-Al2O3 composites were successfully prepared by vacuum thermal pressed-internal oxidation sintering process. The basic properties and microstructure of the composites were tested and observed. The hot compression deformation tests of TiC(30vol%)/Cu-Al2O3 composites were conducted at deformation temperature of 450-850 ℃, strain rate of 0.001-1 s-1 and deformation amount of 50% by Gleeble-1500D simulator. By analyzing and caculating the flow stress, constitutive equation and model of dynamic recrystallization critical strain were constructed. By the inflection point of work hardening rate-strain curves and the minimum value criterion of corresponding partial derivative curves, the function relationship between dynamic recrystallization critical strain and Zener-Hollomon parameter was constructed. The results show that the softening mechanism of dynamic recrystallization is a feature of true stress-true strain curves of TiC(30vol%)/Cu-Al2O3 composites, and the peak stress increases with the decrease of deformation temperature or the increase of strain rate. The calculating thermal deformation activation energy is 211.384 kJ/mol. -
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