Core‐Shell Heterostructural Design Enables Spark Plasma Sintered Ti‐Zn Alloys With Superior Mechanical Properties

Pure titanium (Ti) as a substitute for load‐bearing bone implants still faces potential challenges, including insufficient strength, a mismatched elastic modulus, debris generated from wear against human tissue, and bio‐inertness. Herein, zinc (Zn) is introduced as a bioactive ingredient, and the difference in the physical properties of Ti and Zn elements is managed through a designed two‐step spark plasma sintering process to prepare dense core–shell heterostructural Ti‐Zn alloys consisting of pure Ti cores and Ti‐Zn intermetallic eutectic shells. The well‐bonded core–shell interfaces, the effect of dislocations and twins within the Ti cores, and the hetero‐deformation‐induced strengthening collectively contribute to the superior tensile and compressive properties of Ti‐Zn alloys. Thus, Ti‐7Zn and Ti‐3Zn exhibit the highest tensile and compressive strengths of 694.4 and 2247.4 MPa, respectively. Notably, these alloys simultaneously maintain a low elastic modulus comparable to bone. As the Zn content increases, the hardness and wear resistance improve. Moreover, the wear and corrosion resistance of Ti‐Zn alloys surpasses that of pure Ti, effectively mitigating tissue damage caused by debris and excessive ion release when used as implants. This study can provide insights into the fabrication of bioactive Ti‐based alloys and components with significantly different melting points.