Deformation mechanisms for a new medium-Mn steel with 1.1 GPa yield strength and 50% uniform elongation

作     者：Wei Wang Yanke Liu Zihan Zhang Muxin Yang Lingling Zhou Jing Wang Ping Jiang Fuping Yuan Xiaolei Wu Wei Wang;Yanke Liu;Zihan Zhang;Muxin Yang;Lingling Zhou;Jing Wang;Ping Jiang;Fuping Yuan;Xiaolei Wu

作者机构：State Key Laboratory of Nonlinear MechanicsInstitute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering SciencesUniversity of Chinese Academy of SciencesBeijing 100049China 

出 版 物：《Journal of Materials Science & Technology》 (材料科学技术（英文版）)

年 卷 期：2023年第132卷第1期

页      面：110-118页

核心收录：

学科分类：08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）] 

基　　金：supported by the National Key R&D Pro-gram of China(No.2017YFA0204402) the NSFC Basic Science Cen-ter Program for“Multiscale Problems in Nonlinear Mechanics”(No.11988102) the National Natural Science Foundation of China(Nos.11790293 and 52192591) 

主　　题：Medium-Mn steel Strain hardening Ductility Martensite transformation Strain gradient Mobile dislocations 

摘      要：A new medium-Mn steel was designed to achieve unprecedented tensile properties,with a yield strength beyond 1.1 GPa and a uniform elongation over 50%.The tensile behavior shows a heterogeneous deforma-tion feature,which displays a yield drop followed by a large Lüders band strain and several Portevin-Le Châtelier *** strain hardening mechanisms for excellent tensile properties were ***,non-uniform martensite transformation occurs only within a localized deformation band,and ini-tiation and propagation of every localized deformation band need only a small amount of martensite transformation,which can provide a persistent and complete transformation-induced-plasticity effect dur-ing a large strain ***,geometrically necessary dislocations induced from macroscopic strain gradient at the front of localized deformation band and microscopic strain gradient among various phases provide strong heter-deformation-induced ***,martensite formed by displacive shear trans-formation can inherently generate a high density of mobile screw dislocations,and interstitial C atoms segregated at phase boundaries and enriched in austenite play a vital role in the dislocation multipli-cation due to the dynamic strain aging effect,and these two effects provide a high density of mobile dislocations for strong strain hardening.