铝钛异种合金的激光熔钎焊

提出了一种连接Al/Ti异种合金的新工艺，即采用激光为热源，AlSi12为填充材料，实现了Ti-6Al-4V钛合金和LF6铝合金的激光熔钎焊连接。激光熔钎焊是一种局部加热焊接过程，通过调整激光加热参数，控制填充材料的润湿铺展及界面金属间化合物的形态和数量，从而控制接头质量。在实验过程中，填充焊丝实时送入，通过改变激光功率、间隙大小、光斑尺寸、焊接速度、送丝速度、激光辐照位置等工艺参数，以获得对接头的不同加热效果。研究了不同参数下的钎缝成形规律、接头界面特点及接头拉伸强度。结果表明，采用激光熔钎焊工艺连接Al/Ti异种合金可以获得成形良好、强度较高的接头，但焊接过程对工艺参数要求严格;接头厚度方向不同位置的界面金属间化合物的厚度和形态各不相同;热输入较低情况下，钎料与钛合金材料作用不充分，接头易从界面处断裂;热输入较高时，接头容易从铝合金侧熔合区附近断裂。

Laser Welding-Brazing Al/Ti Dissimilar Alloys with Filler Metal

A novel method, laser welding-brazing is presented to joint Al/Ti dissimilar alloys, in which filler metal is AlSi12 and base metal are Ti-6Al-4V and LF6. With this method, the desirable spatial and temporal temperature distribution can be obtained, and then the shape and quantity of intermetallic compounds can be controlled. In experiments, the process characteristics were investigated with the butted joint, the influence of laser power, gap length, feeding and welding speed, laser irradiation position on the joint appearance, interface behavior and tensile-strength were assessed. The experimental results indicate that the joints with good appearance and high tensile-strength can be achieved with this joining method, although the process requirements are rigorous. The shape and thickness of intermetallic compound layer at different positions in the same joint are various. The joint fracture accrues at the interface between titanium alloy and weld when the heat input is inadequate.