Hot Deformation Behavior and Microstructure Evolution of IN783 Low-Expansion Superalloy
The hot deformation behavior of IN783 low-expansion superalloy was investigated through hot compression experiments at the deformation temperatures of 1000-1120 ℃ and strain rates of 0.01-10 s-1.The microstructure evolution of the alloy under different deformation conditions was studied using electron backscatter diffraction(EBSD).The results indicate that the flow stress of IN783 alloy is significantly decreased with the increase in deformation temperature and the decrease in strain rate.Combined with Arrhenius equation and Zener-Hollomon parameter model,the constitutive equation of the alloy was established as e=3.58237 × 1015[sinh(0.00495724σ)]3 99121.exp(-417.146551/RT),which can well describe the relationship between flow stress and deformation temperature,strain rate of IN783 alloy during hot deformation.The hot working diagram of IN783 alloy was drawn based on the dynamic material model.According to the hot working diagram and the microstructure observation,the safety zone for hot working of IN783 nickel-based superalloy is determined as:1000-1080 ℃/0.1-10 s-1 and 1000-1040 ℃/0.01-0.1 s-1.In addition,under the condition of high temperature and low strain rate(1060-1120 ℃,0.01 s-1),mixed crystal and grain coarsening occur,which makes it not suitable for the hot working of IN783 alloy although the alloy has high power dissipation coefficient in those parameters.
IN783 superalloyhot deformation behaviorhot working mapmicrostructure evolution