铜/石墨复合材料热变形行为研究

通过Gleeble-3500热模拟试验机对铜/石墨复合材料进行热压缩试验，研究变形温度为700～850 ℃、应变速率为0.001～1.000 s^-1时该复合材料的热变行为。通过光学显微镜研究复合材料显微组织的演变，根据实验数据构建该复合材料的本构方程和热加工图。使用Zener-Hollomon参数模型对该复合材料的流变应力进行研究。研究发现，铜/石墨复合材料的流变应力随着应变温度的升高而降低，随应变速度的增大而增大。计算得出该复合材料的热变形激活能为463.02 kJ/mol，表明材料具有良好的成形能力。通过构建的本构方程验证了最大应力的吻合性，发现计算值和试验值的误差在9.5%以内，说明该方程对复合材料的流变行为具有指导作用。热加工图表明了该复合材料的适宜加工温度为780～820 ℃，变形速率为0.050～0.100 s^-1；变形温度为830～850 ℃时，变形速率约为0.001 s^-1。

Hot deformation behavior of copper/graphite composites

The hot compression test of copper/graphite composites was conducted using a thermal simulation testing machine, Gleeble-3500, to study the thermal deformation behavior of the composites at a deformation temperature of 700-850 °C and a strain rate of 0.001-1.000 s^-1. According to the experimental data, the constitutive equation and thermal processing map of the composites were constructed, and the microstructure evolution of the composites was studied by optical microscope. The rheological stress of the composites was studied according to Zener-Hollomon parameter model. The flow stress of the composites decreases with the increase of strain temperature and increases with the increase of strain rate. The calculated thermal deformation activation energy of the composites is 463.02 kJ/mol, which shows that the composites has good formability. The consistency of the maximum stress was verified through the constructed constitutive equation, and it was found that the error between the calculated and experimental values was within 9.5%, indicating that the equation has a guiding role in the rheological behavior of composites materials. The thermal processing map shows that the suitable working temperature is 780-820 °C and the deformation rate is around 0.050-0.100 s^-1, when the deformation temperature is 830-850 °C, the deformation rate is about 0.001s^-1.