Development of Ti 50 Ni 50−X Co x (X = 1 and 5 at. %) Shape Memory Alloy and Investigation of Input Process Parameters of Wire Spark Discharge Machining

The present study discusses, wire spark discharge machining and optimizations of its process parameters (Voltage (V), pulse off duration (Toff), pulse on duration (Ton), wire-speed (WS) and servo feed (SF)) for machining of Ti50Ni49Co1 and Ti50Ni45Co5 alloys conventionally used bone staple material. These alloys are developed through Vacuum arc melting (VAM) for the current investigation. For the elemental analysis, Energy Dispersive X-Ray Spectroscopy (EDX) investigations have been performed for the developed alloys. A hybrid combination of optimization techniques is used for parametric optimization in WSDM. The Grey relational analysis (GRA) Entropy measurement methods and response surface methodology (RSM) are used for formulating a hybrid combination of optimization techniques. Such type of technique is rarely implemented to get optimum machining conditions for wire spark discharge machining of TiNiCo alloy to achieve a higher metal removal rate with a better surface finish. Response surface design (DOE) is applied for an experimental plan and created L-33 orthogonal array. Machining has been carried out of TiNiCo alloy as per the experimental plan and measured the machining responses (metal removal rate and average roughness). Experiment numbers 26 and 18 are found optimum machining conditions for Ti50Ni49Co1 and Ti50Ni45Co5 alloy, respectively, which is also confirmed by confirmation test results. Moreover, 6.52 mm3/min higher metal removal rate has been noticed for the Ti50Ni49Co1 and 8.538 mm3/min metal removal rate for Ti50Ni45Co5 alloy which means metal removal rate is increasing with increased the percentage of Co in TiNi which is also confirmed by scanning electron microscopy images. A similar trend has been observed for the average roughness.