Effect of Rake Angle and Feed Rate on the Surface Quality While Turning In Situ TiB2/7050 Al Metal Matrix Composites

Abstract

In situ TiB2/7050 Al metal matrix composites are processed by mixed-salt reaction method to improve the interfacial reactions and enhance the material properties. However, the lack of research on its machinability limits its wide application in the industry. In the present study, the effects of rake angle and feed rate on the surface quality while turning in situ TiB2/7050 Al metal matrix composites have been investigated. Three types of polycrystalline diamond (PCD) tools with 0° ∼ 5° ∼ 10° rake angles were utilized in this work. The surface roughness, surface topography and residual stress profile developed in TiB2/7050 Al composites by cylindrical turning were evaluated. The experimental results reveal that feed rate has more significant impact for surface roughness than rake angle. The smooth surface topography without void and defects indicates that the chips are formed in ductile mode. Unlike other metallic alloys, the surface residual stress of TiB2/7050 Al composites are always in compressive state. In addition, the increase of feed rate contributes to deeper residual stress penetration layer. Through the discussion in this study, the role of TiB2 reinforcement particles on the machinability of TiB2/7050 Al composites can be better understood.