高锰Hadfield钢单向拉伸变形及断裂行为研究  

Research on Monotonic Tension Deformation and Fracture Behavior of the High Manganese Hadfield Steel

作　　者：肖罡[1,2,3] 卜晓兵 杨钦文[1] 杨旭静[1] 冯江华[2] XIAO Gang;BU Xiaobing;YANG Qinwen;YANG Xujing;FENG Jianghua(State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha 410082;CRRC Zhuzhou Institute Co. , Ltd, Zhuzhou 412001;Hunan Provincial Key Laboratory of High Efficiency and Precision Machining of Difficult-to-Cut Material, Hunan University of Science and Technology,Xiangtan 411201;China Automotive Technology & Research Center Co. , Ltd, Tianjin 300300)

机构地区：[1]湖南大学汽车车身先进设计制造国家重点实验室,长沙410082 [2]中车株洲电力机车研究所有限公司,株洲412001 [3]湖南科技大学难加工材料高效精密加工湖南省重点实验室,湘潭411201 [4]中国汽车技术研究中心有限公司,天津300300

出　　处：《材料导报》2019年第22期3811-3814,共4页Materials Reports

基　　金：中国博士后科学基金(2019M652755);湖南省自然科学基金(2018JJ3178);难加工材料高效精密加工湖南省重点实验室开放基金(E21751);湖南科技大学博士科研启动基金(E51783)~~

摘　　要：本研究测试了高锰Hadfield钢室温下在大应变速率(分别为6×10^-3 s^-1、6×10^-4 s^-1、3×10^-5 s^-1和6×10^-6 s^-1)范围内的单向拉伸变形的力学响应行为,分析了合金的变形行为及裂纹萌生与扩展规律。结果表明:在不同应变速率下均存在动态应变时效现象,且延伸率具有正的应变速率敏感性。拉伸变形后,奥氏体晶粒内产生了大量位错和层错,以及细小且相互平行的形变孪晶。应变硬化率随真应变的增加依次表现为“减小—增大—减小”三个演变阶段。其中,第二阶段的增大现象是形变孪晶的急剧增加而形成孪生硬化所致。垂直于拉伸变形方向分布的高密度滑移带是裂纹萌生的主要区域。裂纹扩展以沿垂直拉伸方向的穿晶形式为主,结合沿孪晶方向进行。高锰Hadfield钢的主要变形机制是滑移与孪生的相互竞争。The monotonic tensile test of the high manganese Hadfield steel has been investigated at various strain rates of 6×10^-3 s^-1 , 6×10^-4 s^-1 , 3×10^-5 s^-1 and 6×10^-6 s^-1 . The deformation behavior and the crack initiation and propagation phenomenon of the steel have been analysed. The results illustrate that the studied alloy shows dynamic strain aging under all the selected strain rates. The ductility exhibits a positive strain rate sensitivity. A mass of dislocations and stacking faults are generated in the austenite grain after deformation, together with the generation of parallel tiny deformation twins. The strain hardening rate experiences three stages of “decrease-increase-decrease”, in which the second stage attributes to the continuous produce of deformation twins. The high density slip band perpendicular to the tension direction is beneficial for the initiation of crack. The crack is propagated in the transgranular form, together with propagation along twin form. The competition between gliding and twinning is the main deformation mechanism of the tested steel.

关 键 词：高锰Hadfield钢 应变硬化 断裂 变形机制 

分 类 号：TG142.1[一般工业技术—材料科学与工程]