Ultrasonic vibration assisted turning for reducing tool wear in metal matrix composite machining

In automotive and aerospace industry there is a continuous research of materials with particular properties, as high specific strength, high specific stiffness, and wear resistance. Part of this research is focusing on particulate-metal-matrix-composites (PMMC), made of a metal matrix, as aluminium alloy or titanium alloy, and reinforcements which typically are hard particles, as silicon carbide SiC or titanium carbide TiC. The effects of reinforcements are an improvement of mechanical, thermal, chemical properties in respect of the monolithic alloys, but the same hard particles cause a severe tool wear, affecting machining time, costs of the tools, and final surface roughness. The purpose of this thesis is to study the tool wear during turning of an MMC, composed with a matrix of a series 3003-aluminium alloy, and a %30 in volume of SiC. A tungsten carbide tool with a physical vapor deposition coating of titanium aluminium nitride WC - PVD TiAlN was used, and the machining process was conducted with two techniques, conventional turning, and ultrasonic vibration assisted turning (UVAT), a technique to assist the machining process giving to the tool ultrasonic frequency vibrations. The machining procedure was made with a fixed depth of cut, three different feed rates, four different cutting speeds and two different machined volumes. After every machining process the flank wear was measured and was found that ultrasonic vibration assisted turning decreases the wear of the tool. In addition, it was made the analysis of the chips for every machining process.