Dislocations across interphase enable plain steel with high strengthductility  

位错越过相界使廉价钢具有高强塑性

作　　者：Jiazhi Zhang Yanguang Cui Xunwei Zuo Jianfeng Wan Yonghua Rong Nailu Chen Jian Lu 张家志;崔岩光;左训伟;万见峰;戎詠华;陈乃录;吕坚(Shanghai Key Laboratory of Materials Laser Processing and Modification,School of Materials Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China;Department of Mechanical Engineering,City University of Hong Kong,Greater Bay Joint Division,Shenyang National Laboratory for Materials Science,Hong Kong 999077,China;Shanghai Nuclear Engineering Research and Design Institute,Shanghai 200233,China)

机构地区：[1]Shanghai Key Laboratory of Materials Laser Processing and Modification,School of Materials Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China [2]Department of Mechanical Engineering,City University of Hong Kong,Greater Bay Joint Division,Shenyang National Laboratory for Materials Science,Hong Kong 999077,China [3]Shanghai Nuclear Engineering Research and Design Institute,Shanghai 200233,China

出　　处：《Science Bulletin》2021年第11期1058-1062,M0003,共6页科学通报（英文版）

基　　金：supported by the National Natural Science Foundation of China(51771114 and 51371117);the National Key R&D Program of China(2017YFA0204403);the Key Projects of National Natural Science Foundation of China(51031001)。

摘　　要：Low cost,high strength and high elongation steel is always the major trends of steel development especially for automotive industry.However,raising strength usually brings about loss of ductility,which is known as the strength-ductility trade-off[1].Solving strength-ductility trade-off by increasing low cost carbon content is the century-long pursuit of researchers.Rashid[2]pointed out that investigation since 1900s indicates that the increase of carbon content leads to enhancing strength,but deteriorating ductility and other properties of steels.低成本、高强塑性一直是汽车用钢的发展趋势.然而钢的强度和塑性通常相互排斥,即强度的提高将导致塑性的下降.本文设计了一种廉价的高碳淬火-分配-回火(Q-P-T)钢,与其他钢相比,展现出最高的性/价比;而且通过碳含量的增加,同时提高了Q-P-T钢的强度和塑性,实现了百年来研究者的愿望.本文发现了Q-P-T钢在拉伸过程中位错越过马氏体/奥氏体界面(DAMAI),从马氏体运动到奥氏体的现象.DAMAI效应有效地提高了马氏体的形变能力,从而显著地提高了高强度马氏体钢的塑性.DAMAI效应随后被透射电镜原位动态拉伸观察和分子动力学模拟所证实.本文进一步提出了基于DAMAI效应的增塑策略,即通过碳从马氏体到残留奥氏体的分配来平衡残留奥氏体含量和其稳定性,由此增强DAMAI效应,并尽可能减少脆性的应变诱发孪晶马氏体,该增塑策略将为开发高强塑性马氏体钢提供新路径.

关 键 词：残留奥氏体 马氏体钢 孪晶马氏体 强度和塑性 高强塑性 汽车用钢 动态拉伸 相互排斥 

分 类 号：U465.11[一般工业技术—材料科学与工程] TG142.1[机械工程—车辆工程]