Effects of Cu-Coated SiC Content on Microstructure and Properties of Laser Cladding SiC(p)/Al–Si Composite Coatings

SiC particles (SiC(p))-reinforced Al–Si matrix composite coatings were synthesized on 4032 aluminum alloy by laser cladding using powder mixtures of Al-20 wt.% Si alloy and electroless copper-plated SiC particles (SiC(p-Cu)). The effects of SiC(p-Cu) content on microstructure, phase composition, and microhardness of the SiC(p)/Al–Si laser cladding layer (LCL) were investigated systematically. The results showed that the microstructure of SiC(p-Cu)/Al–Si LCL was mainly composed of undissolved SiC(p), lump-like primary Si, lump-like Al(2)Cu, plate-like Al(4)SiC(4), and Al–Si–Cu ternary eutectic. In addition, the eutectic microstructure became finer with the increasing of SiC(p-Cu) content. The average microhardness of the LCL increased with the increasing of SiC(p-Cu) content. When SiC(p-Cu) content was 50 wt.%, the average microhardness of the LCL reached 508 HV(0.05), which was about 3.5 times larger than that of the substrate. The LCL reinforced with a SiC(p-Cu) content of 30 wt.% exhibits the best wear resistance.