Improvement on the wire EDM characteristics of zirconia filled Al7050 (Al-Zn-Cu-Mg) alloy composite using Taguchi coupled TOPSIS method

Abstract

Wire electrical discharge machining (WEDM) is an cutting edge non-traditional techniques for producing complicated 3D forms in rigid materials with greater dimensional accuracy. The aim of the investigation was, to predict the WEDM characteristics of ZrO₂ ceramic addition of Al7050 alloy composite by employing Taguchi coupled Technique for order preference by similarity to ideal solution (TOPSIS) approach. The work material was manufactured by stir casting process utilizing 12 wt.% of ZrO₂ particulates in Al7050 alloy matrix. The experimental work was carried out as per the L₉ (3³) orthogonal array design by taking input parameters like pulse current (I_p), pulse on-time (T_on) and pulse off-time (T_off), respectively. The impact of the WEDM parameters on the material removal rate (MRR) and surface roughness (SR) were determined by analysis of variance (ANOVA). Based on the TOPSIS approach, the higher MRR (0.32251 g/min) with lesser SR (3.982 µm) were achieved at the ‘I_p’ of 25 amps, ‘T_on’ of 115 µs and ‘T_off’ of 60 µs. ANOVA results explored that the ‘T_on’ was identified as the primary impact factor on MRR and SR, subsequently by ‘I_p’ and ‘T_off’ with contribution of 44.23%, 36.53%, and 12.16%, respectively. Moreover, the surface topography of the machined composite surface was analyzed through scanning electron microscopy (SEM). It was clearly revealed the formation of surface defects such as craters, micropores, cracks and also the appearance of a recast layer on the machined surface.