Investigation on TIG welding of mixed gas for SiCp-reinforced aluminum matrix composite

摘要

Taking the He-Ar mixed gas as protected atmosphere, the weldability of TIG welding for SiCp/6061 Al composites were investigated without and with Al-Si filler. The tensile test of weld joint with filler was conducted. The microstructure and fracture morphology of the bead were observed. The results show that adding 50% helium (vol. %) in shielding gas improves arc stability and provides the seams with high quality appearance. Compared with the weld formability of composites with and without Al-Si filler having 12% Si, the high quality appearance welded seam is obtained when the Al-Si filler added. In addition, the interface reaction between SiC and matrix is greatly depressed. The microstructure of the welding joint has evident non-uniformity and there are a lot of reinforcement phases in the weld center. The average tensile strength of weld joints with Al-Si filler is above 70% of the matrix composites as annealed condition.