超声辅助瞬间液相扩散连接异种金属AZ31/LY12成形规律及组织性能研究

Study on Formation Regularity and Microstructure and Properties of AZ31/LY12 Dissimilar Metal Bonded by Ultrasonic-assisted Transient Liquid Phase Bonding

研究了采用超声辅助瞬间液相扩散焊(U-TLP)连接镁铝异种材料的成形规律、接头显微组织和力学性能,着重分析了不同施加超声时间对金属间化合物形成规律、显微组织形态及力学性能的影响。结果表明:在460℃下施加超声5 s即可有效破除镁铝表面的氧化膜,实现镁铝在大气环境下的有效连接。超声可以促使反应层发生挤出效应,使焊缝宽度变小,可以破碎枝状晶,提高形核率,细化晶粒。焊缝的主要成分是Al3Mg2、Al12Mg17、Al Mg和α-Mg。镁铝接头的剪切强度大小与焊缝厚度成反比,当超声时间为5 s时剪切强度达到最大值,为28.36 MPa,断裂方式为解理断裂,断裂位置是Al3Mg2和Al母材之间。

The formation regularity, microstructure and mechanical properties of magnesium and aluminum dissimilar material joints by ultrasonic-assisted transient liquid phase bonding(U-TLP) were studied. The effects of different ultrasonic time on the formation of intermetallic compounds, microstructure and mechanical properties were analyzed. The results show that the oxide film on magnesium and aluminum alloys can be effectively broken when the ultrasonic is applied for 5 s at460 ℃, and the effective connection of magnesium aluminum in atmospheric environment can be realized. Ultrasound can promote extrusion effect of the reaction layer, making the weld width smaller. Ultrasonic can break dendritic crystals,improving the nucleation rate and refining the grains. The main components of the weld are Al3 Mg2, Al12 Mg17, Al Mg andα-Mg. The shear strength of the welded joint of the magnesium and aluminum is inversely proportional to the thickness of the weld. When the ultrasonic time is 5 s, the shear strength reaches the maximum value, which is 28.36 MPa. The fracture method is cleavage, and the fracture position is between Al3 Mg2 and Al base metal.