Abstract In this study, electron microscopy was employed to examine the microstructure evolution mechanisms and dynamic recrystallization kinetics in low and medium carbon steels with a lamellar structure of perlite during equal channel angular pressing (ECAP) at 400 °C. Mechanisms of the subgrain structure formation and its transformation into a grain-subgrain structure with average element size of 200–500 nm were revealed. It was found that new ultrafine grains with high-angle boundaries are formed in the ferrite phase as a result of dynamic recrystallization beginning after the second ECAP pass. It was shown that the growth rate of the recrystallized fraction increases drastically after 3 ECAP passes. Fragmentation of ferrite lamellas within perlite colonies and strain induced split of cementite plates was detected suppressing the recrystallization in AISI 1045 steel. Enhanced mobility of dislocations in ferrite phase of AISI 1020 steel assisted in severe strain hardening and subsequent dynamic recrystallization.

中文翻译：

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ECA温压过程中低碳钢和中碳钢的动态再结晶动力学

摘要 本研究采用电子显微镜研究了具有珍珠岩层状结构的低碳和中碳钢在 400 °C 等通道角挤压 (ECAP) 过程中的微观结构演变机制和动态再结晶动力学。揭示了亚晶结构形成的机制及其向平均元素尺寸为 200-500 nm 的晶粒-亚晶结构的转变。发现作为第二次 ECAP 道次后开始的动态再结晶的结果，在铁素体相中形成了具有大角度边界的新超细晶粒。结果表明，经过 3 次 ECAP 后，再结晶部分的生长速率急剧增加。检测到珍珠岩群内铁素体片层的碎裂和渗碳体板的应变诱导分裂抑制了 AISI 1045 钢的再结晶。AISI 1020 钢铁素体相中位错迁移率的增强有助于严重应变硬化和随后的动态再结晶。