Hot deformation and dynamic recrystallization of TiC(30vol%)/Cu-Al₂O₃ composites

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.