High speed, high power density laser-assisted machining of Al-SiC metal matrix composite with significant increase in productivity and surface quality

摘要

Al-SiC metal matrix composites (MMCs) are promising materials for aerospace and electronic packaging applications. However, machining of Al-SiC MMC is very challenging, often resulting in surface scratches by the hard SiC particles and extensive tool wear. Recent approaches of laser assisted machining using low cutting speeds and low laser power densities, although reduce the tool wear, lead to overheating of the bulk material and their irreversible thermal deformation. Here we report a new approach of high speed and high-power density laser-assisted turning (LAT) of an Al-SiC MMC (Al2124 + 17 vol% 0.3 mu m SiC). The high cutting speed allows the surface of the locally heated parts to be removed timely avoiding the excessive heat transfer from the surface layer to the main body, which also greatly improves the productivity. The diameter of the laser beam spot (0.7 mm) is smaller than the nose radius of the turning insert (0.8 mm) so that the heat generated from the laser radiation can be effectively removed by the chips. As a result, overheating of the entire part is avoided. The maximum laser power density in this work is 3.38 x 10(6) W/cm(2), which is two orders of magnitude higher than that reported in previous LAT publications. A cutting speed of 565 m/min can be achieved leading to over 2.7-140 times increase in productivity compared with previously reported values, and the surface quality has also been substantially improved in addition to reduced tool wear.