Microstructure and Mechanical Properties of Weld Metal of SiC_P/LD2 Composite
The SiCP/ LD2 alloy composite was welded by using MIG with addition of Al-Si or Al-Mg filler metal. The mi- crostructure of weld metal was analysed with OM and TEM, and the properties of weld metal were analysed with MTS-810 testing system. The results show that when welding with Al-Mg filler metal, serious reaction between Al matrix and SiC particles occurred in the molten pool, and a quantity of large -size acicular Al4C3 formed in the weld metal. With Al-Si filler metal used, the interfacial reaction between Al matrix and SiC particles is alleviated remarkable, only a little small-size acicular Al4C3 is found in the MIG weld, It is also found that Si in welding wire can prevent from the formation of hot-crack in weld. The mechanical testing results show that tensile strengths and elongation of welds deposited with Al-Si filler metal is higher than those of welds deposited with of Al-Mg filler metal.