Towards load-bearing biomedical titanium-based alloys: From essential requirements to future developments

The use of biomedical metallic materials in research and clinical applications has been an important focus and a significant area of interest, primarily owing to their role in enhancing human health and extending human lifespan. This article, particularly on titanium-based alloys, explores exceptional properties that can address bone health issues amid the growing challenges posed by an aging population. Although stainless steel, magnesium-based alloys, cobalt-based alloys, and other metallic materials are commonly employed in medical applications, limitations such as toxic elements, high elastic modulus, and rapid degradation rates limit their widespread biomedical applications. Therefore, titanium-based alloys have emerged as top-performing materials, gradually replacing their counterparts in various applications. This article extensively examines and highlights titanium-based alloys, along with an in-depth discussion of currently utilized metallic biomedical materials and their inherent limitations. To begin with, the essential requirements for load-bearing biomaterials are introduced. Then, the biomedical metallic materials are summarized and compared. Afterward, the microstructure, properties, and preparations of titanium-based alloys are explored. Furthermore, various surface modification methods are discussed to enhance biocompatibility, wear resistance, and corrosion resistance. Finally, the article proposes the development path for titanium-based alloys in conjunction with additive manufacturing and the novel alloy nitinol.