Study on Laser Melt Injection Coatings Reinforced with TiC/WC Ceramic on Aluminum Alloy Surface AITranslate

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Chinese Library Classification Number:TG174.4[金属学及工艺—金属表面处理]

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To enhance the surface wear resistance of aluminum alloy,TiC/WC ceramic-reinforced coatings were fabricated in situ on a 7075 aluminum alloy substrate via laser melt injection.The microstructures and mechanical properties of the coatings with varying numbers of laser remelting cycles were investigated using metallographic microscope(OM),field emission scanning electron microscope(FESEM),X-ray diffractometer(XRD),Vickers hardness tester,nanoindenter,and ball-on-disk tribometer.The results indicate that in the TiC-reinforced coating,a small portion of the remelted TiC particles adhere to the surface,while the majority sediment at the bottom,leaving the intermediate region devoid of TiC.The grains of the TiC coating coarsen after remelting,exhibiting a columnar morphology.In contrast,the WC-reinforced coating shows nearly complete aggregation of the remelted WC particles at the bottom,forming a distinct ceramic layer.With increasing remelting cycles,the grain size of the WC coating decreases.However,after five remelting cycles,cracking of WC particles results in visible cracks within the coating.Both types of coatings exhibit significantly lower hardness compared to the aluminum alloy substrate,with a general decreasing trend as the number of remelting cycles increases.Similarly,the fracture toughness of both coatings decreases with additional remelting.In terms of wear resistance,both coatings demonstrate lower wear rates than the substrate,with the TiC coating showing a notably lower wear rate than the WC coating.As the number of remelting cycles increases,the wear rates of both coatings rise.Therefore,increasing the number of laser remelting cycles adversely affects key mechanical properties,namely hardness,fracture toughness,and wear resistance,in TiC/WC ceramic-reinforced coatings,thereby compromising the overall performance of the coatings.This study achievement can provide a reference for improving the wear resistance of aluminum alloy surface.