Influence of Cold Spray on the Microstructure and Residual Stress of Resistance Spot Welded Steel-Mg

摘要

A mixture of Al_2O_3 and pure-Al powder was successfully deposited on weld nugget of the spot weld dissimilar metals Mg and galvanized steel. The cross-sectional microstructure was analyzed using SEM. Also, residual stress was measured through hole drilling and X-ray diffraction methods. The obtained microstructure analysis shows that mixture of Al and Fe with a continuous layer of ～2.7 μm were observed at the interface of weld nugget/coat. At the same time, equiaxed grains were observed near the interface. In contrast, the Zn containing interlayer thickness of ～14 μm with porosity was identified at the interface of the coating on the Zn coated steel. The hardness distribution also revealed that the interface obtained lower hardness compared to the substrate and coating. At the same time, the residual stress also changes through thickness of the coating to the substrate which will improve the corrosion and fatigue properties.