关键词: 爆炸复合钢板, 拉伸, 原位观察, 界面缺陷

Abstract: For 304L / 533B explosive 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 in 304L / 533B explosive 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 304L side of interface is ascribed to the refined grain, while the decreased hardness in the 533B 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 533B side comes from the sharped plastic deformation. By contrast, the specimen fractured comes from the microcrack in the fine grain zone of 304L side 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 533B side comes from the main crack merged with the microcracks initiated from the interfacial defects.

Key words: explosive welded composite steel, tensile, in situ observation, interfacial defect