Abstract Hot compression tests of a novel hot-extruded (HEXed) P/M nickel-based superalloy at the temperature of 1020–1110 °C with the strain rate of 0.001–1 s−1 were carried out on a thermal simulated test machine. The microstructure evolution and nucleation mechanisms of DRX were analyzed by employing optical microscope (OM) and transmission electron microscope (TEM). The results indicate that the true stress-true strain curves of the superalloy exhibit typical features of dynamic recrystallization (DRX). The flow stress is reduced with the increasing deformation temperature or decreasing strain rate. Based on the friction-modified true stress-true strain curves, the activation energy for hot compression of the superalloy is determined to be 1175.1 kJ/mol, and the constitutive equation as well as the DRX kinetics models is established. Elevating deformation temperature or reducing strain rate can promote the proceeding of DRX. Various nucleation mechanisms of DRX are found to occur during hot deformation of the novel superalloy, which include the dominant DDRX, assisting twin-induced nucleation and CDRX, and possible γ′ stimulated nucleation.

中文翻译：

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一种新型 HEXed P/M 镍基高温合金的热变形和动态再结晶

摘要 在热模拟试验机上对一种新型热挤压 (HEXed) P/M 镍基高温合金在 1020-1110 °C 和 0.001-1 s-1 的应变速率下进行了热压缩试验。采用光学显微镜(OM)和透射电子显微镜(TEM)分析了DRX的微观结构演变和成核机制。结果表明，高温合金的真应力-真应变曲线表现出典型的动态再结晶（DRX）特征。流动应力随着变形温度的升高或应变速率的降低而降低。基于摩擦修正的真应力-真应变曲线，确定高温合金热压缩活化能为1175.1 kJ/mol，并建立了本构方程和DRX动力学模型。提高变形温度或降低应变速率可以促进DRX的进行。在新型高温合金的热变形过程中发现了 DRX 的各种成核机制，包括占主导地位的 DDRX、辅助孪生诱导成核和 CDRX，以及可能的 γ' 受激成核。