Innovative design of heterogeneous structures in Cu-containing titanium alloys to enhance mechanical properties, abrasion resistance, and antibacterial performance

How to precisely modulate the morphology and distribution of precipitated phases to have long-term antibacterial activity and outstanding strength-ductility has slowed the overall development and engineering applications of Cu-bearing biomedical titanium alloys. For the first time, the electron beam powder bed fusion (EBPBF) was employed to design titanium alloys with a completely solid solution, and containing fine Ti₂Cu precipitates in both uniform and layered structures. The mechanical properties of the designed alloy with the layered (α-Ti and Ti₂Cu) structure are superior to the other structures, especially with an outstanding compressive yield strength of 1221.9 MPa. Simultaneously, the wear resistance of the heterogeneous structures containing Ti₂Cu precipitates was significantly improved, with a specific wear rate only half of that of the EBPBF-fabricated Ti6Al4V alloy. The compact arrangement of Ti₂Cu phases created a large number of interfaces conducive to the formation of corrosion channels, which provided the capacity of continuous Cu²⁺ release. This work comprehensively analyzes the effects of heterogeneous structures on enhancing the sustained antibacterial capacity and optimizing the mechanical properties of a Cu-containing titanium alloy, laying a good foundation for their application in clinical and implantable devices.