Abstract A novel advanced high-strength steel Fe79.85Cr2.07Ni2.62Si2.68B0.5Mn12C0.23 (wt%) was designed in laboratory scale. Steel microstructures under conditions of cast ingot, cold rolling, annealing and after tensile deformation were characterized by means of scanning electron microscopy, electron backscattered diffraction, X-ray diffraction and transmission electron microscopy. The corresponding mechanical properties were analyzed. Results showed that a high number density of nano-sized boride particles precipitated in austenite matrix, which contributed to grain refinement during annealing and deformation. The M2B boride was confirmed to be of bcc crystal structure and exhibited 1 1 ¯ 2 M 2 B / / 200 γ , 1 ¯ 11 M 2 B / / 011 γ orientation relationships with austenite matrix. The differential C–J analysis was used to understand work-hardening behaviors of steel samples subjected to various annealing processes. It was indicated that the tensile deformation was divided into three stages and each stage was associated with a distinct work-hardening exponent n value. A good combination of tensile strength (1260 MPa) and elongation (25%) was achieved as a result of enhanced work hardening behavior concerning mechanisms of dislocation glide, strain-induced martensitic transformation and mechanical twinning.

中文翻译：

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一种冷轧新型先进高强钢的设计：微观组织演变和力学性能分析

摘要 以实验室规模设计了一种新型先进高强度钢Fe79.85Cr2.07Ni2.62Si2.68B0.5Mn12C0.23 (wt%)。采用扫描电子显微镜、电子背散射衍射、X射线衍射和透射电子显微镜对铸锭、冷轧、退火和拉伸变形后钢的显微组织进行了表征。分析了相应的力学性能。结果表明，在奥氏体基体中析出高数量密度的纳米级硼化物颗粒，这有助于退火和变形过程中的晶粒细化。M2B硼化物被证实为体心立方晶体结构，与奥氏体基体显示出1 1 ¯ 2 M 2 B / / 200 γ 、1 ¯ 11 M 2 B / / 011 γ 取向关系。微分 C-J 分析用于了解钢样品经过各种退火工艺的加工硬化行为。结果表明，拉伸变形分为三个阶段，每个阶段都与不同的加工硬化指数 n 值相关。由于位错滑移、应变诱发马氏体转变和机械孪晶机制的加工硬化行为增强，因此实现了抗拉强度 (1260 MPa) 和伸长率 (25%) 的良好组合。