Investigations on the effect of electrical discharge machining process parameters on the machining behavior of aluminium matrix composites

Abstract Extensive applications are found in aluminum matrix composites, where high strength to weight ratio, low weight and high corrosion resistance are needed. One of the categories of such materials is the SiC reinforced aluminum matrix composite. This reinforcing material belongs to ceramic group of materials and can withstand high temperature and improve several properties when incorporating in the grain structure of the base matrix. The introduction of SiC enhances wear resistance, hardness value and tensile strength. However, the use of high percentage of SiC material reduces the machinability (ductility) and toughness resistance and the machining of such material becomes difficult. In this current study, an attempt is made to develop an aluminum (LM25 alloy) matrix composite, which is reinforced with 7%SiC and 3%Gr particulates through stir casting route. The fabrication of composite is followed by evaluating the machining behavior of hybrid composite through electric discharge machining. During machining, current, voltage, pulse on time and pulse off time are selected as input controllable variables while material removal rate (MRR), tool wear rate (TWR) and over cut are chosen as responses. The experiments are carried out as per Taguchi's L9 OA, with the aid of ANOVA and significant parameters effecting responses are identified. Main effects plots are drawn and optimum set of input machining conditions are determined.