Zhou Songbo, Hu Feng, Wang Kun, Hu Chengyang, Zhou Wen, Yershov Serhii, Wu Kaiming, Zhang Zhicheng, Pan Xianming
The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, China.
Collaborative Innovation Center for Advanced Steels, Wuhan University of Science and Technology, Wuhan 430081, China.
Materials (Basel). 2022 Aug 30;15(17):5996. doi: 10.3390/ma15175996.
A two-step bainitic treatment with a final isothermal temperature below M was adopted to obtain bainitic steel with abundant retained austenite (RA). Nanoindentation testing was used to investigate the stability of RA in bainite steel and clarify the effect of RA on the deformation of medium-carbon steel. The results showed that, in contrast to the traditional one-step approach, a greater amount of nanoscale RA film was obtained using the two-step treatment. This was due to a lower final bainitic transformation temperature, which induced a higher carbon concentration in the untransformed austenite in the stasis stage; this resulted in untransformed austenite with a higher carbon content existing as RA rather than forming martensite in the subsequent cooling process. In addition, it was determined that the increased stability of RA during the two-step transformation delayed the pop-in point.
采用两步贝氏体处理，最终等温温度低于M点，以获得具有大量残余奥氏体（RA）的贝氏体钢。利用纳米压痕试验研究贝氏体钢中残余奥氏体的稳定性，并阐明残余奥氏体对中碳钢变形的影响。结果表明，与传统的一步法相比，两步处理获得了更多的纳米级残余奥氏体薄膜。这是由于较低的最终贝氏体转变温度，导致停滞阶段未转变奥氏体中的碳浓度较高；这使得碳含量较高的未转变奥氏体以残余奥氏体的形式存在，而不是在随后的冷却过程中形成马氏体。此外，还确定了两步转变过程中残余奥氏体稳定性的增加延迟了压入点。
