Hot Deformation Behavior of ATI 718Plus Alloy with Different Microstructures

In this work, the effect of microstructure on hot deformation behavior of ATI 718Plus (hereinafter refers to 718Plus) alloy was studied by isothermal compression test. The results showed that when the strain rate was 0.01–0.1 s−1 with deformation temperature of 980 and 1030 °C, hot deformation behavior was mainly affected by dislocation density. Dislocation density of the air-cooling alloy was larger than that of the furnace-cooling alloy, which makes its critical strain smaller and peak stress higher than that of the furnace-cooling alloy. When the strain rate was 1 s−1, hot deformation behavior of the alloy was mainly affected by twins and γ′ phase, and high-density deformation twins in air-cooling alloys resulted in higher critical strain. γ′ phase exists in furnace-cooling alloy, which makes its peak stress higher than that of air-cooling alloy. 718Plus alloy is sensitive to cooling rate; dislocation and γ′ phase have obvious effects on its hot deformation behavior.