拉伸载荷下304L/533B爆炸复合板界面损伤的原位观察  

In Situ Observation on Interfacial Damages of 304L/533B Explosive Welded Composite Steel Sheet under Tensile Loading

作　　者：刘丽丽[1] 轩福贞[1] 

机构地区：[1]华东理工大学,上海200237

出　　处：《中国机械工程》2016年第23期3235-3240,共6页China Mechanical Engineering

基　　金：国家自然科学基金资助项目(51325504)

摘　　要：针对304L/533B爆炸复合钢板,进行了扫描电镜下外加载荷的原位实验,观察分析了界面及其缺陷的演化规律。结果表明:304L/533B爆炸复合钢板界面呈周期性循环波形状态,界面处存在孔洞、未融合和夹杂初始缺陷,界面304L侧产生的细晶区导致纳米硬度升高,533B侧的脱碳区导致硬度减小。平行和垂直界面加载条件下,界面孔洞和未融合缺陷均发生沿加载方向的形变和边缘微裂纹,而夹杂缺陷的变化不明显。然而界面缺陷均未对试样的宏观强度产生影响,垂直界面方向拉伸载荷下试样的断裂源于界面533B侧等轴晶区的塑性形变,而平行于界面方向拉伸载荷下试样的破坏源于304L侧的微裂纹。剪切载荷下界面孔洞和未融合缺陷形成了沿界面的微裂纹,其与剪切主裂纹的合并导致了试样在533B侧发生剪切破坏。For 304L/533 Bexplosive welded composite steel sheet,in situ tensile experiments were carried out in the chamber of scanning electron microscopy（SEM）.Damage evolution of the interfaces and original defects were analyzed.The results show a periodically sine-shaped interface in304L/533 Bexplosive welded composite steel sheet,and three kinds of defect such as micro-voids,non-fusion and micro-inclusion around the interface are observed.A sharply increased nano-hardness in the 304 Lside of interface is ascribed to the refined grain,while the decreased hardness in the 533 B side of interface is caused by decarburization.Under the loading conditions of parallel to the interface and perpendicular to the interface,both of interfacial voids and nonfusion is deformed along the loading direction and the cracks are initiated at the edge of micro-voids.In addition,no significant changes of inclusions are detected.But the strength of composite steel sheet is not influenced by the interfacial defects.For load direction being perpendicular to the interface,the specimen fractured in the equiaxial grains zone of 533 Bside comes from the sharped plastic deformation.By contrast,the specimen fractured comes from the microcrack in the fine grain zone of 304 Lside under the load direction being parallel to the interface.Under the shear load conditions,microcracks are initiated from the interfacial voids and nonfusion defects along the interface.The specimen failed at the 533 Bside comes from the main crack merged with the microcracks initiated from the interfacial defects.

关 键 词：爆炸复合钢板 拉伸 原位观察 界面缺陷 

分 类 号：TG156[金属学及工艺—热处理]