A Comparative Study on the Powder-Mixed Electric Discharge Machining (PMEDM) of Novel Ti29Nb13Ta4.6Zr (TNTZ) Biomedical Alloys: The Effect of C and O Atoms

The Ti29Nb13Ta4.6Zr (named as TNTZ) alloy is a unique candidate for biomedical applications due to super properties such as its non-toxic and non-allergenic nature, ideal Young's modulus, and excellent biocompatibility. Machining of biomaterials is a fundamental requirement of parts manufacturing and an important element of the efficiency and performance of bioecosystems. This study investigated the powder-mixed electric discharge machining (PMEDM) performance of TNTZ alloys, a solution treated and modified with 0.2O and 0.2C wt% atoms. The effects of PMEDM parameters, including EDM current and pulse-on time on the machining of modified TNTZ alloys, were investigated using Taguchi experimental design. The evaluation focused on surface roughness (SR) and material removal rate (MRR). The machined surface's white layer and overall surface quality were analyzed using 3D topographic analysis, scanning electron microscopy and energy-dispersive spectrometry-chemical. The results indicated that PMEDM caused the formation of a melting-recasting white layer, which exhibited a correlation with discharge energies such as SR and MRR. Furthermore, the treated surface and section displayed volcanic craters, holes, a few cracks, debris-covered in molten metal, and reinforcement particles. Analysis of variance showed the percentage contribution of current, materials, and pulse-on time is 18.06%, 14.64%, and 3.97%, respectively. The contribution of pulse interaction on time-current was the highest at 23.60%.