Experimental investigation on WEDM parameters of Ni-rich nitinol plate

Abstract

Wire Electro discharge machining (WEDM) process is extensively employed to fabricate miniaturized products. Ni-Ti shape memory alloy (Nitinol) finds its primary application in many significant engineering areas and biomedical fields because of its inherent properties, like shape recovery, superior biocompatibility, and elasticity. The current research investigates the shape recoverability characteristics of WEDM machined nitinol. WEDM Experiments were conducted through DOE with significant input factors like the current (I), pulse on time (Ton), and Wire Feed (f). The responses recorded are material removal rate (MRR), wire wear rate (WWR), percentage of shape recovery (R), kerf width (w), and surface roughness (Ra). The mathematical model developed was to predict the response for corresponding input factors, and the variances of the model are analyzed. Significant contributors are identified from ANOVA, and surface plots are drawn to show the interaction effects. The morphological behavior of the surface was analyzed by FESEM and compositional analysis by EDAX. Surface topography is analyzed in surface roughness, and microhardness was measured to understand the process relevant to shape recoverability better. The results reveal that current and pulse on time affect the microhardness and surface roughness, altering the machined alloy’s shape recoverability.