Effect of Ti on microstructure and properties of laser welding weld of SiC particle reinforced 6092 Al alloy matrix composite

Ti foils of different thickness are used as filler materials to analysis the effects of different amount of Ti elements on microstructure and mechanical properties during laser welding of SiCp/6092 aluminum matrix composites. The results show that the addition of Ti foil can effectively improve the fluidity of the molten pool, thereby reducing the technologic porosities in the weld zone. At the same time, adding Ti foil can avoid the low melting point element burnt caused by the direct laser irradiation on the base material. Under the irradiation of the laser, the Ti foil is completely melted and metallurgical reacted with the matrix metal which is melted by the action of heat conduction. When the content of Ti element is too little, the interface reaction can not be effectively suppressed, and a large number of brittle phases are still distributed in the weld. Ti element does not significantly improve the mechanical properties of the welded joint. When the content of Ti element is too much, the Ti element fails to diffuse in the molten pool, and the excess Ti element reacts with aluminum to form Al₃Ti. The over-grown Al₃Ti is in the shape of sheet, which will be detrimental to the mechanical properties of the joint. Therefore, adding an appropriate amount of Ti element to the molten pool is beneficial to improve the metallurgical reaction of the molten pool, thereby improving the mechanical properties of the joint, and the maximum tensile strength of the welded joint can reach 206 MPa.