Microstructure Evolution and Processing Map of Superalloy GH720Li during Isothermal Compression

摘要

Isothermal compression tests for superalloy GH720Li were conducted to investigate the effect of hot deformation parameters on microstructure evolution. The changing characteristics of flow stress during hot deformation were also studied. The flow instability area was calculated based on Prasad Plastic Instability Criterion and the hot processing map was obtained. The results showed that dynamic recrystallization was the main softening mechanism of GH720Li alloy during hot deformation. The peak and steady stress decreased significantly with an increase of test temperature and a decrease of the strain rate. Finally, three unstable areas have been found from the processing map.