Processing of silicon carbide particulate reinforced aluminum alloy composites using rotary electrochemical discharge machining

As a kind of metal matrix composites, silicon carbide particulate reinforced aluminum alloy composites (SiCp/Al) have been widely applied in numerous fields. However, it is still difficult to process this composite material with electrical discharge machining (EDM) at present. To address this problem, this study introduces a novel rotary electrochemical discharge – chemical composite machining (RECDM-CM) method. This method uses rotating electrodes and workpieces to improve the flushing effect of working medium and utilizes the electrolysis to reduce the recast layer thickness. The chemical reaction between sodium carbonate (Na2CO3) and aluminum oxide (Al2O3) at high temperatures is used to remove the non-conductive Al2O3 in this composite machining. Rotary electrochemical discharge – chemical composite machining is used to process silicon carbide particulate reinforced AA2009 aluminum alloy composites with the silicon carbide volume fraction of 55%. The experimental results reveal that the material removal rate (MRR) of rotary electrochemical discharge – chemical composite machining is 5.2 times that of rotary electrical discharge machining, and its relative tool wear rate (RTWR) is 37.42% of rotary electrical discharge machining. The recast layer thickness is reduced to less than 13 μm via rotary electrochemical discharge – chemical composite machining.