No abstract

Metals or alloys when reinforced with more than one reinforcement materials are generally considered as hybrid metal matrix composites (MMCs). The superior properties of the hybrid MMCs deter its wide applications due to the difficulty in machining. Wire electrical discharge machining (WEDM) is an effective unconventional machining process which can be used to machine difficult to machine materials. This work is aimed towards optimizing the WEDM parameters to achieve better surface roughness ( Ra) during machining of stir cast unreinforced A17075 alloy and A17075/B4C/Al2O3 based hybrid MMCS. The experiments were carried out as per central composite design of response surface methodology (RSM). It is observed that all the process parameters such as pulse-on time ( TON), pulse-off time ( TOFF), wire feed (F), gap voltage (V) considered in this work were significant.

This investigation is aimed towards the optimization of wire electrical discharge machining (WEDM) parameters of the hybrid MMCs consisting of aluminium alloy (Al7075) reinforced with boron carbide (B4C) and alumina (Al2O3) particles at four distinct volume fractions. The effect of important WEDM parameters such as pulse-on (TON), pulse-off (TOFF), gap voltage (V) and wire feed (F) on material removal rate (MRR) and surface roughness (Ra) are studied. The experiments are carried out as per L9 orthogonal array (OA) using design of experiments (DOE) approach. Analysis of variance (ANOVA) is used to identify significant parameters for achieving higher MRR and lower Ra. From the study, it is observed that increase in percentage volume fraction of the reinforcements resulted with decrease in MRR but increase in the Ra value. Regression equations are presented to represent the relationship between input and output parameters.