关键词: 镍基高温合金, 热变形, 元胞自动机, 动态再结晶, 亚动态再结晶

Abstract: Single-pass and double-pass hot compression tests for Ni-Cr-Mo-based superalloy Hastelloy C276 were conducted by Gleeble thermal-mechanical simulator, and the flow stress curves and microstructure under different hot deformation conditions were obtained. On this basis, the physical metallurgy models as well as the parameters were determined, and then the cellular automaton model was established for topological evolution of microstructure. The results show that the dynamic recrystallization is prone to occur of the Hastelloy C276 superalloy during high temperature compression. When the dynamic recrystallization is not complete, the recrystallized grains will further grow rapidly during the heat preservation or the hot compression pass intermittence, so that metadynamic recrystallization will occur. The recrystallization behavior of the Hastelloy C276 superalloy is sensitive to the hot processing parameters, including the deformation temperature, strain rate, strain and so on. The dislocation density evolution, recrystallization nucleation, and migration of grain boundary, etc during the heat preservation and the hot compression pass intermittence can be calculated simultaneously by the constructed cellular automaton model, which can be used to predict both the microstructure topological structure evolution and the stress-strain response of the Hastelloy C276 superalloy during high temperature compression effectively.

Key words: nickel-based superalloy, hot deformation, cellular automaton, dynamic recrystallization, metadynamic recrystallization