Abstract: A SiC particle reinforced alum inum alloy metalmatrix composite, SiC_P/6061A lMMC, is welded by laser beam w elding using nickel p lates as alloying fillermetal. M icrostructure of thew eld ischaracterized as functions of laser p rocessing parameters. Results show that the dissolution ofreinforcement SiC particles and formation of the needle-like harmful Al₄C₃ phases are noticeablysupp ressed using nickel as the alloying filler metal. The new reinforcements, such as Al₃Ni, AlNi,etc, are p roduced in-situ in theweld by laser beam w elding of SiC_P/6061AlMMC using nickel plate asalloying filler metal.