铝/钛异种合金激光熔钎焊接头特性

以C02激光为热源，以A1Si12焊丝为填充材料，对Ti-6Al-4V钛合金和5056铝合金异种材料激光熔钎焊进行研究，采用SEM、EDS、XRD和金相显微镜分析接头的微观结构特征，通过拉伸实验评定接头的力学性能。研究结果表明：所得接头具有熔焊和钎焊双重性质，即铝母材局部熔化，为熔化焊，而钛母材与焊缝金属之间存在金属间化合物层钎焊界面；钎焊界面上部的金属间化合物层组成复杂，可分为2层，即呈针状或芽状的Ti-Al-Si系金属间化合物层和以Ti-Al系金属间化合物为主的连续层；钎焊界面下部的金属间化合物层较薄；拉伸试样断裂倾向于发生在紧邻钎焊界面的焊缝上，平均抗拉强度为298．5MPa。

Characteristics of laser welding-brazing joint of Al/Ti dissimilar alloys

Laser welding-brazing(LWB) of Ti-6Al-4V and 5056Al was conducted using AlSi 12 filler metal.The microstructure characteristics of LWB Al/Ti joints were analyzed by SEM,EDS,XRD and optical microscopy.The joint strength was measured via tensile test.The results show that the joint has dual characteristics and can be divided into a welding part on the aluminium side and a brazing part on the titanium side.An intermetallic compound layer forms at the brazing interface between mixed seam metal and titanium.The intermetallic compound layer at interfacial top includes an acicular Ti-Al-Si intermetallic layer and a continuous Ti-Al intermetallic layer near titanium alloy.The intermetallic compound layer at interfacial bottom is thin and different from that at top.The average tensile strength of joints is 298.5 MPa.Fracture is prone to occur in the seam metal nearby brazing interface.