剪切应变速率对经循环正反扭转处理的奥氏体钢微观结构及性能的影响

Zhang Zhimin, Dong Qingshan, Song Bo, He Hong, Chai Linjiang, Guo Ning, Wang Bingshu, Yao Zhongwen

School of Materials and Energy, Southwest University, Chongqing 400715, China.

Department of Mechanical and Materials Engineering, Queen's University, Kingston ON K7L3N6, Canada.

Materials (Basel). 2019 Feb 7;12(3):506. doi: 10.3390/ma12030506.

In this work, commercial AISI 304 stainless steel rods were subjected to cyclic forward/reverse torsion (CFRT) treatments at low-speed and high-speed torsion at room temperature. Microstructures in the core and surface layers of the CFRT-treated samples were systematically characterized. Results show that the CFRT treatment can introduce martensite phase on the surface of the rods via strain-induced martensitic transformation. High-speed twisting is more effective in inducing martensite in the surface layer compared to low-speed twisting. During the stretching process, the overall strain-hardening behavior of the gradient material is related to the content of its gradient defects. Higher gradient martensite content results in a higher surface hardness of the material, but less overall tensile properties. The effect of twisting speed on torsion behavior and the strain-hardening mechanisms in tensile of the gradient structured steels was also addressed.

在这项工作中，商用AISI 304不锈钢棒在室温下进行了低速和高速循环正向/反向扭转（CFRT）处理。对CFRT处理样品的芯部和表层微观结构进行了系统表征。结果表明，CFRT处理可通过应变诱导马氏体相变在棒材表面引入马氏体相。与低速扭转相比，高速扭转在表层诱导马氏体方面更有效。在拉伸过程中，梯度材料的整体应变硬化行为与其梯度缺陷含量有关。较高的梯度马氏体含量导致材料表面硬度较高，但整体拉伸性能较低。还探讨了扭转速度对梯度结构钢扭转行为和拉伸应变硬化机制的影响。