Hot deformation behavior of GH4169 superalloy with high proportion of recycled material addition and initial dendrite structure

This research delves into the hot deformation characteristics of as-cast GH4169 superalloy, incorporating a substantial proportion of recycled material. Through conducted hot compression tests across a range of temperatures (900–1100 °C) and strain rates (0.005–1 s−1), the study aims to elucidate the deformation behavior under these conditions. By integrating microstructural observations, the optimal hot processing window has been determined, and the factors influencing the thermal activation energy have been thoroughly discussed. The intrinsic model and the dynamic recrystallization volume fraction model have been developed by analyzing the stress-strain curves of the as-cast GH4169 alloy. The flow stresses exhibit a systematic evolution with changes in deformation temperature and strain rate, highlighting significant work-hardening characteristics. The thermal processing maps reveal that a strain rate of 0.005–0.011 s−1 and a deformation temperature of 1030 °C to 1100 °C constitute the optimal processing interval for the as-cast GH4169 alloy. This interval is found to be more confined compared to that of the homogenized alloy. The activation energy for hot deformation across different states of the GH4169 alloy is ranked as follows: homogenized state, forged state, forged solid solution state, and as-cast unhomogenized state. The results of this study not only provide a theoretical basis for the application of as-cast GH4169 alloy in the actual forging process of billets, but also provide scientific guidance for the optimization of production costs in the future. © 2024 Elsevier B.V.