Friction Stir Forming of A5083 Aluminum Alloy Gear-Racks with WC Particles Embedded in Tooth Surface

摘要

This paper proposes a new forming process for gear racks featuring a tooth-surface stiffening layer. The proposed process is as follows. First, a JIS A5083P aluminum alloy plate on which a surface modifier of WC particles and vaseline paste had been applied was put on a gear-rack die. Next, friction stirring was conducted on the back surface of the plate. The material then deformed and precisely filled the cavity of the die. WC particles were embedded into the surface of the aluminum alloy matrix due to high pressure and heat caused by friction stirring. The forming conditions and the corresponding results, including the distribution of WC perticles on the tooth surface, are investigated in the study. WC particles were embedded near the surface mechanically, and only a very few particles were observed inside the matrix. With an undefill condition, WC particles are concentrated on the rear surface of the tooth, which contacts the tail side of the die. In contrast, No significant particle density differences were observed among the profile of teeth with a fully filled condition in the die cavity.