热输入对钛铝异种合金激光自熔钎焊接头组织与力学性能的影响

Effect of Heat Input on Microstructure and Mechanical Properties of Laser Self Fluxing Brazed Ti/Al Dissimilar Alloy Joints

使用IPG 6000光纤激光器对TC4钛合金与6061铝合金进行对接焊,通过激光束偏移到铝侧,获得钛铝异种合金的激光自熔钎焊接头,通过金相显微镜、扫描电镜以及拉伸测试等分析了热输入对TC4/6061钛铝异种接头组织以及力学性能的影响。结果表明,当焊接热输入超过133 J/mm,较多的脆性金属间化合物在界面生成,金属间化合物主要为TiAl3以及TiAl2;当热输入小于133 J/mm,金属间化合物层很薄且在1μm左右,金属间化合物主要为TiAl3。当焊接热输入为107 J/mm时,TC4/6061钛铝异种接头抗拉强度最大,达到212 MPa,约为6061铝合金的63%,接头断裂方式为韧脆混合型断裂。

The TC4 titanium alloy and 6061 aluminum alloy were butt welded by using IPG 6000 fiber laser.The laser self fluxing brazed joint was obtained with the laser beam shifting to the aluminum side.The effect of heat input on the microstructure and mechanical properties of TC4/6061 titanium aluminum dissimilar joint was analyzed by metallographic microscope,scanning electron microscope and tensile test.The results show that when the heat input exceeds 133 J/mm,more brittle intermetallic compounds are formed at the interface,and the main intermetallic compounds are TiAl3 and TiAl2.When the heat input is less than 133J/mm,the intermetallic layer is very thin,about 1μm,and the main intermetallic compound is TiAl3.When the heat input is 107J/mm,the maximum tensile strength of TC4/6061 dissimilar joint is 212 MPa,which is about 63%of that of 6061 aluminum alloy.The fracture mode of TC4/6061 dissimilar joint is ductile brittle mixed fracture.