Machinability of B4C-reinforced Al2014 metal matrix composites in electric discharge machining

This study was conducted to clarify the effect of various variables such as the type of electric discharge machining, discharge current and reinforcement content of B4C-reinforced Al alloy metal matrix composite on workpiece removal rate, electrode wear rate and material removed per discharge pulse, which are not extensively explored in the literature. B4C-reinforced Al2014 matrix composite samples containing 5 and 10 vol.-% B4C particles, produced by vacuum infiltration method, were machined with electric discharge machining and powder mixed electric discharge machining at various discharge current settings. In both types of machining processes, the workpiece removal rate and electrode wear rates decreased and increased, respectively, when the reinforcement contents of the composites increased. However, powder-mixed electric discharge machining enhanced the machining stability, and a comparatively higher workpiece removal rate was observed with a decreased electrode wear rate. On the other hand, by increasing the discharge current, which was also verified as the most effective machining parameter in variance analysis, both workpiece removal rate and electrode wear rate values increased in both machining techniques. The experimentally calculated volumetric workpiece material removed by a discharge pulse was compared to that of a model in the literature, and they were also found to be consistent with each other.