Investigation of effects of MgO ratio on the surface quality and tool wear in turning Al-MgO composites

Abstract

In this study, specimens of Al-MgO metal matrix composites with reinforcement-volume ratios of 5%, 10% and 15% were produced using vacuum infiltration method. The produced specimens were then tested for machining on computer numerical control lathe using carbide, cubic boron nitride and coated cubic boron nitride cutting tools. Machining tests were performed under dry cutting conditions with three different feed rates (0.075, 0.15 and 0.225mm/rev), four different cutting speeds (150, 200, 250 and 300m/min) and fixed depth of cut (1mm). The test results indicate that surface roughness (Ra) values for machined composite specimens were reduced as the cutting speed was increased, but increased as the feed rate was increased. The highest Ra values were observed at cutting speed of 150m/min and at feed rate of 0.225mm/rev. In general, the most stable results were achieved with C tools. The scanning electron microscope images of cutting tools suggest that the tip of tools had built-up edge and abrasive wear mechanism was effective on all of the cutting tools; and C tools, in general, provided the most stable results.