Effect of beam swing parameters on microstructure and properties of SiCp/Al composites by laser welding

For SiCp / Al composites, SiC particles will react with Al matrix to form needle-like brittle phase Al4C3 during high temperature melting, which will deteriorate the welding performance of the joint and seriously restrict the welding application of the material.To improve the microstructure and properties of welded joints, the effects of different laser swing parameters on the microstructure and properties of SiC particle reinforced Al matrix ( SiCp / 6005A ) composites were studied. The Linear ( I ), Circle ( O ), 8, Infinity ( ∞ ) swing modes and the difference of laser welding forming under different swing frequencies and amplitudes were analyzed. The results show that the influence of swing parameters on the formation of Al4C3 by SiC is comprehensive. Appropriate swing parameters can inhibit the growth of needle-like brittle phase Al4C3 in the weld, thereby ameliorating the microstructure and properties of the composite joint, reducing the welding porosity, obtaining the weld with good surface and improving the tensile strength of the weld. Under the Linear ( I ) swing, the smaller the swing frequency in the range of 50 ~ 200Hz, the lower the content of brittle phase Al4C3 in the weld structure, and the better the mechanical properties. When the swing amplitude is 1mm, the maximum tensile strength can reach 220Mpa. The tensile specimen breaks along the needle-like brittle phase Al4C3 at the weld, and the hardness of the weld in the joint is generally higher than that in other areas.