Magnesium/aluminum bi-metallic castings offer significant mass saving opportunities in automotive structural applications. A “zincate+galvanizing” surface treatment has been developed for aluminum alloys to provide improved wetting and metallurgical bond with molten magnesium in bi-metallic casting, due to the removal of Al2O3 layer and the formation of with a very thin metallic zinc film on the aluminum surfaces. The bi-metallic experiments using a selfdesigned high-vacuum test apparatus provided valuable understanding of the interfacial phenomena of Mg (AM60)/ Al (6061) bi-metallic samples. The test results show significantly improved shear strength in the bi-metallic samples with “zincate+galvanizing” surface treatment. It is recommended to adjust the pre-heating temperature and time of the aluminum substrates to control the interfacial reactions for optimum interfacial properties in the actual bi-metallic casting processes.
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