为提高焊接过程的稳定性,拓展最佳的工艺参数范围,采用能量均匀分布的矩形光斑对V形及Y形坡口的钛/铝异种合金进行激光熔钎焊(LWB),获得了在不同线能量条件下的界面微观组织及接头的力学性能。采用扫描电镜(SEM)及金相显微镜对接头界面的微观组织进行观察,结果发现,界面反应层厚度依赖于焊接线能量大小,并且从接头的上部到下部逐渐变薄;界面反应层厚度的不均匀分布对接头的力学性能有很大影响。根据抗拉强度测试的结果发现Y形坡口的焊接接头存在着混合型断裂、焊缝处断裂和界面处断裂三种断裂模式,而V形坡口的焊接接头存在着焊缝处断裂和界面处断裂两种断裂模式; 接头的最高抗拉强度为290 MPa,可达铝母材的80%以上。

To improve the stability during welding and extend the range of optimal technical parameter, joining of Ti/Al dissimilar alloys with V-shape and Y-shape groove respectively is performed by rectangle spot laser welding-brazing(LWB) with homogenize energy distribution. Interfacial microstructure and mechanical property of the joints with different line energies are obtained. The interfacial characteristics of the joints are investigated by scanning electron microscope (SEM) and metallographic microscopy. Results indicate that the thickness of the interfacial reaction layer, which depends on welding line energy, decreases from the top to the bottom of the joint. The unequal thickness of the reaction layer plays a great role in tensile strength of the joint. According to the results of tensile test, joints with Y-shape groove have mixed fracture and fractures in the seam and in the interface. Joints with V-shape groove have fractures in the seam and in the interface. Tensile strength of joint is 80% of the Al alloy matrix up to 290 MPa.