Surface modification of AC2B aluminum alloy castings using friction thermomechanical process

Abstract

Although many surface modification technologies had been proposed and applied to ferrous materials, a few methods can be capable to improve the surface properties of aluminum alloy castings. The present paper proposes a novel process, called friction thermomechanical process (hereafter referred as FTMP) for surface modification of AC2B aluminum alloy castings. In this process, a non-consumable rod is forced to contact the substrate under specified load while rotating. The friction heat, generated at the interface between the rod and substrate, makes substrate surface metal plasticized. The coarse cast microstructures on the substrate surface have been continuously refined due to dynamic recrystallization. As the result, surface modification of AC2B aluminum alloy castings was performed by FTMP, where the zone within 3 mm depth from surface was treated with hardness increment and refined microstructures in this experiment.