Design of high strength and wear-resistance β-Ti alloy via oxygen-charging

Titanium (Ti) is a promising biomedical material due to its superior corrosion resistance, low elastic modulus and favorable biocompatibility. Nevertheless, Ti faces a dilemma because of its inferior abrasion performance and strength-ductility trade-off, which poses a limitation in application as biomedical implants. Here, we developed an oxygen-charging method to fabricate a β-Ti alloy with combination of ultrahigh surface hardness, strength, toughness and remarkable wear resistance. The superior mechanical performance of β-Ti alloy originates from a 200 μm-thick α+β phase hard shell, a 600 μm oxygen gradient region and an oxygen-free β-Ti core. The gradient phase and composition structures display different deformation mechanisms, transforming from simple but unusual basal slip in α phase to multiple-slip activities in β phase. The unique oxygen gradient distribution makes β-Ti alloy much stronger and tougher that can resist surface crack propagation and sample catastrophic failure. Oxygen charging is a novel technique to design high-performance Ti implants for biomedical applications. © 2022 Acta Materialia Inc.