板条马氏体拉伸塑性行为的原位分析  

In Situ Analysis of Plastic Deformation of Lath Martensite During Tensile Process

作　　者：石增敏 梁静宇 李箭[2] 王毛球[3] 方子帆 SHI Zengmin;LIANG Jingyu;LI Jian;WANG Maoqiu;FANG Zifan(Hubei Key Laboratory of Hydroelectric Machinery Design&Maintenance,China Three Gorges University,Yichang 443002,China;School of Materials Science and Engineering,Huazhong University of Science and Technology,Wuhan 430074,China;Special Steel Institute,Central Iron and Steel Research Institute,Beijing 100081,China)

机构地区：[1]三峡大学水电机械设备设计与维护湖北省重点实验室,宜昌443002 [2]华中科技大学材料科学与工程学院,武汉430074 [3]钢铁研究总院特殊钢研究所,北京100081

出　　处：《金属学报》2021年第5期595-604,共10页Acta Metallurgica Sinica

基　　金：国家重点基础研究发展计划项目No.2010CB630802;国家自然科学基金项目No.51201093;湖北省技术创新专项(重大项目)No.2017AAA113。

摘　　要：采用原位中子衍射分析技术测试了板条马氏体钢的拉伸塑性行为,采用Z-Rietveld和卷积多重全曲线拟合方法对衍射数据进行拟合分析。板条马氏体内的位错为刃、螺型位错的混合位错,并呈现随机分布特征。马氏体的加工硬化需要同时考虑位错密度和位错类型2个因素的作用。随着拉伸应变量的增加,螺型位错数量减少,刃型位错数量增加,总位错密度增加。硬取向板条束内位错密度增加,呈现加工硬化特征;软取向板条束内位错密度降低,出现加工软化特征。外加应力在硬取向和软取向板条束内产生应力再分配,变形后在板条束内形成长程内应力。Lath martensitic steels are widely used in high strength structural materials. Coherency strains in quenched lath martensite induce huge dislocation densities, which are the sources of the alloys.strength, whereas the way its microstructure functions is still unclear. The plastic deformation behavior of lath martensite in ultrahigh strength steel was investigated using in situ neutron diffraction technology. Diffraction data were analyzed using the Z-Rietveld and convolutional multiple whole profile(CMWP) fitting procedures. Transformation dislocations in the as-quenched martensite were mixed with edge and screw components and showed characteristics of random distribution. Significant work hardening of lath martensite can be better understood by considering the increase in dislocation density along with changes in dislocation arrangement. With increased tensile strain, the total dislocation density increased with the increasing amount of edge-type components and the decreasing amount of screw-type components. The hard orientation packets showed characteristics of work hardening with an increased dislocation density,whereas the soft orientation packets showed characteristics of work softening with a decreased dislocation density. The partitioning of the applied load was carried out within two types of packets, which further promoted the formation of long-range internal stresses after deformation.

关 键 词：超高强度钢 板条马氏体 塑性变形 位错密度 原位中子衍射 

分 类 号：TG142.1[一般工业技术—材料科学与工程]