Direct Metal Deposition of Graphene–Ti28Nb35.4Zr Matrix Composites With Enhanced Mechanical, Corrosion, and Biocompatibility Properties for Bone Implants

This study presents the fabrication of β‐type Ti–28Nb–35.4Zr (TNZ) and graphene nanoplatelet (GNP)‐reinforced TNZ composites (0.1 and 0.2 wt.%) via direct metal deposition (DMD) for orthopedic implant applications. The effects of GNP addition on microstructure, mechanical strength, tribological behavior, corrosion resistance, and cytocompatibility were systematically evaluated. All DMD‐processed samples primarily exhibited β‐phase, while GNP incorporation promoted α″ martensite formation due to oxygen uptake during processing. The 0.1 wt.% GNP addition refined the grain structure, enhancing compressive yield strength by 16% (863 MPa) and maintaining high ductility with a maximum strain >55%. Hardness increased by 17% for the TNZ‐0.1GNP composite, which had the lowest wear volume (0.03 µm 3 ) and minimal debris formation. Electrochemical testing in Hanks’ balanced salt solution revealed enhanced corrosion resistance for TNZ‐0.1GNP with a corrosion rate of 3.88 µm y −1 due to synergistic passivation and barrier effects. The reduced water contact angle (74° ± 5°) indicated improved hydrophilicity and favorable surface energy for biointeractions. Furthermore, human osteoblast‐like SaOS2 cells showed thriving adhesion, proliferation, and complete surface coverage on TNZ‐0.1GNP after 7 days of culture. Overall, DMD‐processed TNZ‐0.1GNP composite exhibited promising mechanical, wear resistance, corrosion and biocompatible performance as load‐bearing orthopedic implant materials.