Effect of the cutting condition and the reinforcement phase on the thermal load of the workpiece when dry turning aluminum metal matrix composites

Aluminum metal matrix composites (Al-MMCs) are two-phase high-performance materials. The reinforcement of aluminum alloys enhances the properties of the composite material but leads to poor machinability. The required mechanical work for machining is mostly dissipated into heat. Considerable generated quantities of heat are therefore expected when machining Al-MMCs due to the poor machinability of these composite materials. The machine tool, the tool, and the workpiece are thus subjected to a thermal load, which decreases the accuracy of machining. The thermal load increases moreover when dry turning due to the missing heat convection through the cutting fluid. It is therefore necessary to investigate the effect of the reinforcement phase and the cutting condition used on the thermal load of the workpiece in dry turning. Therefore, composites with different reinforcement phases and the non-reinforced aluminum matrix were used as the workpiece materials. The reinforcement differs regarding the volume percent and the average size of the silicon carbide particulate reinforcements. The results revealed that the thermal load and the thermal expansion of the workpiece are significantly affected by the cutting condition used and the reinforcement phase. High cutting speeds and feeds and moderate depths of cut need to be used in order to decrease the thermal load of the workpiece. The Al-MMC workpieces are subjected to greater thermal loads than the workpieces of the non-reinforced alloy. However, better machining accuracies were achieved in dry turning the Al-MMCs.