High-temperature stability of retained austenite and plastic deformation mechanism of ultra-fine bainitic steel isothermally treated below Ms  

作　　者：Ting-ting He Feng Hu Kun Wang Wen Zhou Li Li Serhii Yershov Kai-ming Wu 

机构地区：[1]The State Key Laboratory of Refractories and Metallurgy,Wuhan University of Science and Technology,Wuhan 430081,Hubei,China [2]Collaborative Innovation Center for Advanced Steels,Wuhan University of Science and Technology,Wuhan 430081,Hubei,China [3]Zhejiang Tsingshan Iron and Steel Co.,Ltd.,Qingtian 323903,Zhejiang,China

出　　处：《Journal of Iron and Steel Research International》2024年第8期2014-2030,共17页钢铁研究学报（英文版）

基　　金：The authors gratefully acknowledge the financial support from the National Natural Science Foundation of China(52071238);Leading Innovation and Entrepreneurship Team in Zhejiang Province(2021R01020);the Key Research and Development Program of Hubei Province(2021BAA057);Science and Technology Program of Guangxi Province(AA22068080);the 111 Project.

摘　　要：The mechanical properties of the sample and the stability of retained austenite were studied by designing two kinds of ultra-fine bainitic steel with different heat treatment methods austempering above and below Ms(martensite start tem-perature),which were subjected to tensile tests at 20 and 450℃,respectively.The results show that compared to room temperature(20℃)tensile properties,the uniform elongation of the sample at high temperature(450℃)significantly decreased.Specifically,the uniform elongation of the sample austempered above Ms decreased from 8.0%to 3.5%,and the sample austempered below Ms decreased from 10.9%to 3.1%.Additionally,the tensile strength of the sample austempered above Ms significantly decreased(from 1281 to 912 MPa),and the sample austempered below Ms slightly decreased(from 1010 to 974 MPa).This was due to the high carbon content(1.60 wt.%),high mechanical stability,low thermal stability for the retained austenite of the sample austempered below Ms.Besides,the retained austenite decomposed at high temper-atures,the carbon content and transformation driving force were significantly reduced,the transformation rate increased,and the phase transformation content reduced.

关 键 词：Ultra-fine bainite Isothermal treatment High-temperature tensile property Retained austenite stability Plastic deformation 

分 类 号：TG142.1[一般工业技术—材料科学与工程]