Surface recrystallization of ZE41 to enhance its corrosion behaviour

It is proposed that by microstructural modification of the surface of Mg alloy ZE41, the corrosion resistance of the alloy may improve. This is based on the assumption that the secondary phase in the microstructure of the alloy is responsible for the corrosion and by removing or reducing the secondary phase, the corrosion resistance of ZE41 would improve. Laser surface treatment and friction stir surface treatment are two techniques employed in the present study to carry out this surface microstructural modification on ZE41. New refined microstructures are formed in the modified zones. Corrosion behavior of the surface modified alloy has been compared with the alloy without surface modification, by eletrochemical corrosion tests and elemental analysis of the corroded specimens.The results indicate insignificant improvement in the alloys corrosion resistance as a result of the surface modifications. This lack of improvement in corrosion resistance due to the surface modifications has been discussed on the basis of the nature secondary precipitates in the case of alloy ZE 41, which possibly behaves differently to the precipitates in other common Mg alloys.