不等厚铝/钢激光焊接接头组织与性能研究  

Study on microstructure and properties of laser welded joints of aluminum/steel with different thickness

作　　者：方正帅 刘佳明 黄根哲[1] 张宏[1] 刘凤德[1] FANG Zhengshuai;LIU Jiaming;HUANG Genzhe;ZHANG Hong;LIU Fengde(College of Mechanical and Electric Engineering,Changchun University of Science and Technology,Changchun 130022,China)

机构地区：[1]长春理工大学机电工程学院,长春130022

出　　处：《激光技术》2023年第2期147-153,共7页Laser Technology

基　　金：吉林省科技发展计划资助项目(20190302022GX)。

摘　　要：为了改善铝/钢连接性能,采用激光技术通过调整工艺参数获得了拉伸强度达到铝母材40%的不等厚铝/钢对焊接头,并对接头焊缝组织、界面化合物、力学性能展开了分析。结果表明,焊接速率为1.8 m/min、激光向钢侧偏置0.3 mm、离焦量为0 mm、激光功率为3.0 kW时,接头抗拉强度达到38 MPa;保持其它焊接参数不变,离焦量为-2 mm时,接头抗拉强度进一步提升至57.7 MPa,焊缝截面形状由酒杯状变为束腰状,熔合线更加整齐,附近裂纹、气孔缺陷明显减少;焊缝界面区域物相衍射与能谱分析表明,沿熔合线垂直方向生长的化合物为脆韧程度不尽相同的FeAl、FeAl_(3)、Fe_(2)Al_(5)和Fe_(2)CrAl、Fe_(3)Al;接头整体拉伸断裂模式为脆性断裂,断口表面部分位置连接强度较好,呈凹陷状,检测发现Fe_(3)Al。此研究结果在提升车身铝/钢连接处性能、车身减重以及节能减排方面具有重要现实意义。In order to improve the performance of aluminum/steel connection,an unequal thickness aluminum/steel pair welding head whose tensile strength is 40%of that of the aluminum alloy base metal was obtained using the laser technology by adjusting the process parameters.The joint weld structure,interface compounds,and mechanical properties were analyzed.The results show that the welding speed is 1.8 m/min,the laser is biased to the steel side by 0.3 mm,the defocusing amount is 0 mm,the laser power is 3.0 kW,and the tensile strength of the joint reaches 38 MPa,respectively.With the other welding parameters unchanged,when the defocus amount is-2 mm,the tensile strength of the joint is further increased to 57.7 MPa,the shape of the weld section changes from wine cup shape to corset waist,the fusion line is more neat,and the cracks and porosity defects near it are significantly reduced.Phase diffraction and energy dispersive spectrometer in the interface area of the weld showed that the compounds grown vertically along the fusion line were FeAl,FeAl_(3),Fe_(2)Al_(5)and Fe_(2)CrAl and Fe_(3)Al with different degrees of brittleness.The overall tensile fracture mode of the joint is brittle fracture,the connection strength at some positions on the fracture surface is good,showing a concave shape,and Fe_(3)Al is found through inspection Fe_(3)Al.The results of this study are improving the performance of aluminum/steel joints in the bodywork,weight reduction and energy saving and emission reduction are of great practical significance.

关 键 词：激光技术 不等厚铝/钢 激光焊接 铁-铝化合物 微观组织 力学性能 

分 类 号：TG456.7[金属学及工艺—焊接] TN249[电子电信—物理电子学]