Critical conditions of dynamic recrystallization of TiC/Cu Al₂O₃ composites

In order to determine the dynamic recrystallization behavior of TiC/Cu-Al₂O₃ composites and provide theoretical reference for the development of hot working process parameters. Using the Gleeble-1500D simulator, the hot simulation compression tests of TiC/Cu-Al₂O₃ composites were conducted at deformation temperature of 450-850℃, the strain rate of 0.001-1 s^-1 and total strain of 0.7. The true stress-strain curves of TiC/Cu-Al₂O₃ composites were fitted and analyzed. The work hardening rate of TiC/Cu-Al₂O₃ composites was obtained. The critical conditions of dynamic recrystallization were studied by the inflection point criterion of work hardening rate-strain curves and the minimum value criterion of corresponding partial derivative curves. The results indicate that the softening mechanism of the dynamic recrystallization is a feature of true stress-strain curves of the composites, and the peak stress increases with the decrease of deformation temperature or the increase of strain rate. The inflection point in the work hanrdening rate-strain curve appears and the minimum value of the corresponding partial derivative curve is presented when the critical state is attained for this composite. The critical strain decreases with the increasing deformation temperature and the decreasing strain rate. There is linear relationship between critical stra in, peak strain and Zener-Hollomon parameter.