Wire electro spark machining and characterization studies on Ti50Ni49Co1, Ti50Ni45Co5 and Ti50Ni40Co10 alloys

Abstract

The wire electrical discharge machining process (WEDM) is high demand and influenced by various input process parameters namely pulse duration, voltage, wire diameters and wire material. In this research, a smart material made of TiNiCo alloy is investigated to study the machinability using WEDM process. The pulse duration and servo voltage varied to perform the experiments on Ti50Ni49Co1 Ti50Ni45Co5 and Ti50Ni40Co10 smart materials for bone staple applications which were designed by ELCAM software and generated G-code for machining with same software. L-25 orthogonal array used for machining of selected alloys, which is created (L-25 orthogonal array) through Taguchi design of experiment. From the experiments, an analysis was made to study the amount of material removal and average roughness as a response. Further machined areas were subjected to metallurgical characterization techniques such as surface topography, EDS analysis, residual stress calculation and wear mechanism. Tensile residual stress was noticed at higher values of outputs while lower values of residual stress at lower values of outputs which were also confirmed through microstructure and surface topography that smoother surface has been found at lower values of outputs. Moreover, the higher value of residual stress has been noticed on the machined surface of Ti50Ni40Co10 alloy while lower on the machined surface of Ti50Ni49Co1 alloy. Copper (Cu), Zinc (Zn), Carbon (C) and Oxygen (O) were found as additional elements on the machined surface during the EDS analysis of machined components for each alloy.