T2紫铜-45钢电子束焊双材料界面性能与裂纹偏转

焊接接头性能与缺陷一直是焊接材料相关课题的重要方面，大量的研究描述了焊接材料的接头性能与特征，但异种焊接材料的界面与开裂问题研究并不充分. 文中对T2紫铜-C45钢电子束焊接双材料界面强度和裂纹开裂的问题，首先采用标准拉伸和三点弯曲试验，得到该材料焊缝区抗拉强度、屈服强度、弹性模量参数，并依此计算判断出断裂韧性值；其次对拉伸和三点弯曲试验试样的宏观和微观断口分析，表征其断口形貌特征，得出断口断裂类型为准解理和沿晶脆性复合断裂模式；基于试验分析结果对裂纹开裂偏转路径进行讨论，得出裂纹沿焊缝区扩展并偏向T2紫铜端；最后以实测参数为基准，基于ABAQUS有限元分析得出三点弯曲试验下焊缝区的裂纹扩展和偏转方向结果，为该种异种金属焊接材料接头性能的提升提供了依据.

Study on interfacial properties and crack deflection of the T2 copper-45 steel bimaterial

The performance and flaw of welded joint have always been important aspects of the welding material on this subject. A lot of research has described the performance and characteristics of welding joint materials, but the research about interface of dissimilar welding material and cracking problems is not sufficient. The project is focused on solving the problems of interface strength, microscopic mechanism and crack initiation of the T2 copper-45 steel bimaterial. The four-step measurement starts with using standard tensile and three-point bending experiment to calculate ultimate strength, yield strength and elastic modulus for fracture toughness. The macro/micro fracture morphology of tensile and three-point bending experiment are analyzed, characterizing the fracture surface morphology characteristics. It can be concluded that the fracture types of fracture are quasi-cleavage and intergranular brittle fracture mixed model. The deflection path of crack initiation is discussed and the crack is extended along the weld area and titled towards the T2-copper. Finally, based on experimental testing parameters and ABAQUS finite element analysis, crack propagation and deflecting direction of three point bending test result provide the basis for the improvement of the welded joint performance.