Experimental Study on Electro-Discharge Drilling of NiTiCu10 Shape Memory Alloy

Abstract

Shape memory alloys (SMAs) are potential materials in various areas such as engineering and medicine, and their applications are being studied for practical use. SMAs show competence in their main material properties in response to their working environment or external stimuli. Machining of NiTiCu10 SMAs is difficult using traditional machining because of their wide-ranging mechanical properties like high toughness, strength, and sensitivity to phase transformation temperature. Nonconventional machining methods such as electro-discharge machining (EDM) are suitable for effective machining SMAs. The work material NiTiCu10 SMA has been used in this study, and processed using the vacuum induction melting (VIM) technique. The addition of copper leads to increase in the martensitic transformation temperatures. This paper focuses on the electro-discharge drilling (EDD) of NiTiCu10 SMA using copper tool electrode. Experimental analysis of performance criteria has been evaluated by conducting experiments following one factor at a time (OFAT) approach. Machining features such as material removal rate (MRR), tool electrode wear rate (TEWR), and surface roughness (SR) have been studied by considering pulse current ([Formula: see text]), gap voltage ([Formula: see text]), pulse on time ([Formula: see text]), pulse off time ([Formula: see text]), and rotational speed of tool electrode (N). Experimental results have shown that machining at the highest [Formula: see text] of 12[Formula: see text]A yields the highest MRR with the value of 4.077[Formula: see text]mm3/min, whereas mcahining at [Formula: see text] of 15[Formula: see text][Formula: see text]s yields the lowest TEWR with the value of 0.031[Formula: see text]mm3/min. The lowest SR is 2.8[Formula: see text][Formula: see text]m achieved at the lowest [Formula: see text] of 15[Formula: see text][Formula: see text]s. Surface morphology is significant in quality evaluation in the manufacturing, and building industries because it directly determines the mechanical performance of parts, and the service life of products. Morphological investigation via scanning electron microscope (SEM) has confirmed the formation of craters, debris, microcracks, and resolidified layers. The benefit of this study has been that we have been able to select the range of significant control factors, and predict their levels, for decisive experimentation.