Microstructure evolution during high-strain rate and high-temperature thermo-mechanical processing of a 44MnSiV6 microalloyed steel is investigated using synchrotron high-energy powder X-ray diffraction. The conditions selected replicate a newly developed near solidus high-strain rate process designed for reducing raw material use during the hot processing of steels. High temperatures (exceeding 1300 °C) and high strain rate = 9 s processing regimes are explored. The lattice strains and dislocation activity estimated from diffraction observations reveal that the microstructure evolution is primarily driven by dynamic recrystallisation. A steady-state stress regime is observed during deformation, which develops due to intermittent and competing work hardening and recovery processes. The texture evolution during the heating, tension, shear deformation and cooling stages is systematically investigated. The direct observation of phase evolution at high-temperature and high-strain rate deformation enables a comprehensive understanding of new manufacturing processes and provides deep insights for the development of constitutive models for face-centred cubic alloys.

中文翻译：

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使用同步加速器 X 射线揭示微合金钢在快速高温变形过程中的动态再结晶


使用同步加速器高能粉末 X 射线衍射研究了 44MnSiV6 微合金钢在高应变率和高温热机械加工过程中的微观结构演变。所选择的条件复制了新开发的近固相线高应变率工艺，旨在减少钢材热加工过程中的原材料使用。探索了高温（超过 1300 °C）和高应变率 = 9 秒的加工方案。通过衍射观察估计的晶格应变和位错活动表明，微观结构的演变主要是由动态再结晶驱动的。在变形过程中观察到稳态应力状态，这是由于间歇性和竞争性加工硬化和恢复过程而产生的。系统地研究了加热、拉伸、剪切变形和冷却阶段的织构演变。直接观察高温和高应变率变形下的相演化可以全面了解新的制造工艺，并为面心立方合金本构模型的开发提供深刻的见解。