Machinability of magnesium-alloy reinforced with tricalcium-phosphate: experimental and optimization analysis

Bioimplants require materials that exhibit biocompatibility, biodegradability, high strength and hardness, lightweight characteristics, and superb surface quality. Magnesium is highly valued in bioimplants due to its biodegradability, biocompatibility, and natural presence in the human body. This study primarily focuses on the fabrication of AZ31/β-tricalcium phosphate (TCP) composites via the bottom-pouring stir-casting route and the evaluation of their machinability using electrical discharge machining (EDM). SEM-EDS and XRD analysis confirmed uniform dispersion of TCP particles at 3 wt%, moderately homogeneous distribution at 6 wt%, and significant agglomeration near grain boundaries at 9 wt%. The integration of TCP enhanced compressive strength by 33.14%, 68.57%, and 66.62%, and microhardness by 10.2%, 22.5%, and 16% at 3, 6, and 9 wt%, respectively. The EDM experiments were designed using the Taguchi technique to investigate the effects of TCP wt%, duty cycle, and current on surface roughness (SR), tool wear rate (TWR), and material removal rate (MRR). ANOVA results revealed that current was the most influential factor affecting MRR and TWR, and TCP wt% was the dominant factor influencing SR. Multi-response optimization was performed using grey relational analysis, which identified material level three, duty cycle level one, and current level three as the optimal parameter settings.