SEM原位观察双尺度纳米晶304不锈钢的断裂行为  

Fracture behavior of bimodal nano-crystalline 304 stainless steel in-situ observed with SEM

作　　者：盛捷[1] 喇培清[1] 任军强[1] 马吉强[1] 周学渊 石玉 SHENG Jie;LA Pei-qing;REN Jun-qiang;MA Ji-qiang;ZHOU Xue-yuan;SHI Yu(State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals,Lanzhou Univ.of Tech.,Lanzhou730050,China)

机构地区：[1]兰州理工大学省部共建有色金属先进加工与再利用国家重点实验室,甘肃兰州730050

出　　处：《兰州理工大学学报》2019年第2期10-15,共6页Journal of Lanzhou University of Technology

基　　金：国家自然科学基金(51561020);甘肃省高等学校科研项目(2018A-020);兰州市人才创新创业项目(2017-RC-20)

摘　　要：利用原位拉伸扫描电镜,观察并研究了"铝热反应法"制备出的304奥氏体不锈钢试样经退火与轧制处理后动态拉伸过程中裂纹的萌生与扩展情况及其与双尺度微观组织之间的相互影响关系.结果表明:在拉伸过程中,微裂纹易生成于微米晶和纳米晶间的晶界处,在纳米晶基体中延伸、扩展.裂纹扩展路径受拉伸应力状态以及板材内部晶粒和粗大第二相分布的影响.双尺度组织中微裂纹产生的背应力可有效减缓裂纹扩展速度,从而增强了材料整体的延展性.In-situ tension scanning electron microscope was used to observe and study the germination and propagation of cracks in specimen of 304 austenitic stainless steel, which was prepared by means of aluminothermic reaction method and processed beforehand by annealing and rolling during its dynamic tension process. The mutual influence of bimodal microstructure and cracks on each other was researched, also. The result showed that it would be easy for the microcracks to form at grain boundaries between microcrystalline and nanocrystalline phases and extend and expand in nanocrystalline matrix. The propagation path of cracks would be affected by the tensile stress, grain size, and distribution of bulky second phase. The back stress produced by micro-cracks in bimodal structure could effectively alleviate the speed of crack propagation, so that the overall ductility of the material would be enhanced.

关 键 词：双尺度分布 不锈钢 原位拉伸 断裂行为 

分 类 号：TG142.1[一般工业技术—材料科学与工程]