Effects of process parameters on jet electrochemical machining of SiC particle-reinforced aluminum matrix composites

Abstract

Silicon carbide particle-reinforced aluminum matrix composites (SiCp/Al) are increasingly applied in high-end industries because of their excellent comprehensive material properties. However, as a typical difficult-to-cut material, machining of SiCp/Al using traditional processes faces serious challenges. Jet electrochemical machining (Jet-ECM) is a new-generation electrochemical machining (ECM) technology, which exhibits improved process flexibility and machining accuracy, in addition to the basic advantages of the ECM process. Jet-ECM appears to be a potential alternative machining technology for SiCp/Al to achieve high machining rate and damage-free surface. In the present work, the polarization curves obtained by electrochemistry study showed that a passivation-tanspassivation transition behavior with increasing the voltage occurs in NaNO3 electrolyte, while NaCl electrolyte causes active behavior. Thus, compared to NaCl electrolytes, the NaNO3 electrolyte is relatively suitable for Jet-ECM of SiCp/Al because of its potential to improve the machining localization. Besides, the effects of process parameters (including voltage, electrolyte type, and concentration) on the machining performance were systematically investigated. It was found that the voltage has the most significant influence on the machined dimple profile. A higher voltage helps in achieving a large depth. The surface roughness is dependent on the selection of the electrolyte and voltage. The NaNO3 electrolyte is preferred to realize smooth surface. Additionally, it was found that with increasing voltage, the surface roughness increases. Finally, this work was extended to be Jet-ECM with linear movement of the nozzle, and well-formed SiCp/Al grooves can be obtained using the selected process parameters.