Nanocrystalline Ti-Nb-Ta-Fe0.35-Co0.35 High-Entropy Alloy as a Possible Hard Tissue Implant

Abstract

High-entropy alloys (HEAs) have gained significant interest in medical applications due to their unique functional properties and remarkable strength. For the same, current study prepares Ti-Nb-Ta-Fe0.35-Co0.35 HEA, which exhibits enhanced properties as compared to the corresponding in commonly used implant materials. After validating the composition by a parametric approach, the material has been mechanically alloyed for 50 h to produce single-phase body-centered cubic (BCC) HEA. This has been confirmed by x-ray and electron diffractions. This sample has an average crystallite size of ∼ 7 nm, revealing its nanocrystalline nature. The same powder has been spark-plasma-sintered at 1000 °C to get the high-density product. However, it is transformed into two phases (BCC and hexagonal closed packed), as a phase transformation temperature of ∼ 812 °C is shown by differential scanning calorimetry. The sintered sample has shown compressive strength, ultimate tensile strength, and hardness values as ∼ 1295, ∼ 970 MPa, and ~ 614 HV, respectively, which are greater than those of Ti-6Al-4V and cp-Ti. However, this material has a lower Young’s modulus (∼ 73 GPa) than that of Ti-6Al-4V (∼ 100-110 GPa) and cp-Ti (∼ 90-110 GPa) which makes it a more mechanically suitable candidate for implant application. Its biocompatibility has been evaluated with human osteosarcoma (MG-63) cells by MTT assay and is found to be comparable to that of widely accepted cp-Ti. Hence, this alloy may further be evaluated as future material for implant applications. © ASM International 2024.