Hot deformation behavior and microstructure evolution of spray formed GH738 superalloy

Abstract

In order to evaluate the deformation characteristics of spray formed superalloy GH738, the hot compression test was conducted on Gleeble-3500 thermal mechanical simulator at a temperature range of 960–1120 °C, and a strain rates range of 0.1, 1.0 s−1 with engineering strain 50%. The flow stress data at various hot working conditions was obtained, and the influence of deformation temperature and strain rate on the microstructure evolution of spray formed GH738 was analyzed. The result shows that, the flow stress improves with the increasing of strain rate and the decreasing of temperature, the yield drop is observed on true stress-strain curves at strain rate of 1.0 s−1. The temperature and strain rate have a strongly effect on dynamic recrystallization. Higher temperature could efficiently promote the process of dynamic recrystallization, as the increment of temperature, the dynamic recrystallization grain size shows the tendency of growth. Higher strain rate is better for grain refinement.