The present study was undertaken to identify the appropriate parameter settings for rough and finish machined surface for EN31, H11, and high carbon high chromium (HCHCr) die steel materials in a powder-mixed electric discharge machining process. The effect of seven different process variables along with some of their interactions was evaluated using a dummy-treated experimental design and analysis of variance. Material removal rate (MRR), tool wear rate, and surface finish were measured after each trial and analyzed. The parameter settings for rough and finished machining operations were obtained. EN31 exhibited maximum MRR as compared to the other two materials at similar process settings. Copper (Cu) electrode with aluminum suspended in the dielectric maximized the MRR. Suspending powder in the dielectric resulted in surface modification. Graphite powder showed a lower MRR but improved the surface finish. HCHCr require higher current and pulse on settings for initiating a machining cut and works best in combination with tungsten-Cu electrode and graphite powder for improved finish. The MRR for H11 is lower than EN31 but significantly higher than HCHCr under same process conditions.

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To achieve the enhanced mechanical properties of the titanium grade 5 (Ti64) alloy, multi-layer graphene (MLG) reinforced Ti64 nanocomposites were successfully fabricated by using spark plasma sintering process. Spherical Ti64 particles with an average diameter of 25 μm, MLG with an average diameter of 5 μm, and an average thickness of 2.5 nm were used in the present study. Microstructure study reveals the in-suit reaction between Ti (matrix) and C (reinforcement) that leads to the formation of TiC along the interface. Further, it was observed that a maximum grain refinement of 32.56% occurs in the Ti64/1.2 wt% MLG nanocomposite. Strengthening along the Ti64 and MLG interface and grain refinement are the primary reasons for the enhanced mechanical properties of the nanocomposites. Nanocomposites with 1.2 wt% MLG exhibit nanohardness of 5.29 GPa, elastic modulus of 119.8 GPa which is 68.4% and 140.5% higher compared with that of Ti64 sintered alloy. The results showed that MLG reinforcement plays an important role in improving the mechanical properties of Ti64 nanocomposites.

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Magnesium has gained much attention as advanced light-weight material and have been extensively used in orthopedic applications. Its bone-like properties and non-toxic behavior have established it as a splendid bone implant with excellent biodegradability and biocompatibility; however, its corrosion properties have exploited its usage and need to be addressed. The current study emphasized the influence of rare-earth oxide, that is, Neodymium oxide (Nd2O3/NdO) on the mechanical and corrosion properties of Mg-Hydroxyapatite (HAP) composite. In this work, Mg-HAP-xNdO ( x = 1%, 1.5%, and 2%) was fabricated via powder metallurgy route using Box-Behnken design methodology with different sintering temperatures (400°C, 450°C, and 500°C) and sintering time (1, 2, and 3 h). The results showed that the addition of NdO to the composite developed various intermetallic phases such as Mg12Nd and Nd0.5Ca0.5 as analyzed through FESEM, XRD, and EDS techniques, producing refined microstructure. It was formalized that Mg-HAP composites containing 1.5% NdO, sintered at 400°C for 2 h showed the lowest corrosion rates as compared to other samples. Moreover, the secondary β-phase developed provided necessary reinforcement to the Mg-HAP composites and prevented deformation, resulting in improved microhardness (48.50 HV), ultimate compressive (UCS) (116.57 MPa), tensile strength (UTS) (154.23 MPa) at 1.5% NdO (400°C-2 h). In addition, the statistical analysis performed via the ANOVA technique confirmed the experimental results by revealing significant effects of sintering temperature and combination of all the three parameters on the microhardness and compressive strength of the composites. Hence, these findings concluded that the Mg-HAP-NdO composite could be a promising candidate for orthopedic implant applications.