【摘要】 采用Gleeble-1500D研究了Ni-42W-10Co-1Mo（质量分数，%）中/重合金（MHA）在1150～1300℃和应变速率0.001～1 s^-1下流变行为和微观组织演化规律。结果表明，该合金初始组织由面心立方基体和初生σ相构成。流变应力对变形温度和应变速率敏感，在较高应变速率1s^-1下，应力-应变曲线呈现出典型的动态回复软化特征，而在较低应变速率0.1～0.001 s^-1下变形应力-应变曲线呈现出典型动态再结晶软化特征。基于应力-应变曲线建立了Arrhenius本构方程，并计算得到Ni-42W-10Co-1Mo合金热变形激活能为446.2 kJ/mol。基于动态材料模型构建该合金热加工图，发现在1300℃高应变速率下存在失稳区。通过微观组织分析，揭示其动态再结晶机制主要为不连续动态再结晶，σ相促进动态再结晶优先在其周围形核。最终优化获得了Ni-42W-10Co-1Mo合金最佳的热加工窗口：1250～1300℃，应变速率0.1～0.01 s^-1。更多还原

【Abstract】 The flow behavior and microstructural evolution of a high-density Ni-42W-10Co-1Mo（wt%） alloy were investigated at 1150-1300 ℃ under strain rates of 0.001-1 s^-1 using a Gleeble-1500D. The results show that the initial microstructure is composed of face-centered cubic matrix and σ phase. The flow stress is sensitive to the deformation temperature and strain rate, and the stress-strain curve shows typical dynamic revertive softening characteristics when deformed at 1 s^-1, while typical dynamic recrystallization softening characteristics are observed when deformed at 0.1-0.001 s^-1. The Arrhenius equation was established based on the stress-strain curves, and the hot deformation activation energy of the Ni-42W-10Co-1Mo alloy was calculated to be 446.2 kJ/mol. The thermal processing map was constructed based on the dynamic material model to evaluate the thermal processing performance, and the instable zone was located at 1300 ℃under high strain rate. The deformation microstructural evolution reveals that the dynamic recrystallization mechanism is discontinuous dynamic recrystallization, which preferentially nucleates around the σ phase. Finally, the optimized hot working window for Ni-42W-10Co-1Mo alloy was obtained at 1250-1300 ℃ under strain rate of 0.1-0.01 s^-1.更多还原