Comprehensive review of biological response, alloy design, strengthening mechanisms, performance evaluation, and surface modifications of titanium alloys for biomedical applications

The growing need for plastic surgery, dentistry, and load-bearing orthopaedic bioimplants has directed the search for biomaterials combining long lifespan, biocompatibility, and enhanced mechanical strengths. Due to better crack-growth resistance, corrosion resistance, fatigue resistance, and high specific strength, Ti and its alloys as biomaterials find many varied biomedical applications like stents, dental implants, bone plates, and joints as compared to Co-Cr-based alloy systems and stainless steel. This comprehensive review discusses a broad overview of developments in titanium alloys for medical applications, including low-cost implants with higher biocompatibility, strengthening mechanisms, biological responses, alloy design specially focused on advancements in machine learning models, performance evaluation, surface modifications, and innovations in additive manufacturing/3D printing techniques. The essential elements affecting the reliability, durability, and performance of Ti-based bioimplants include corrosion resistance, fatigue, wear, and strengthening characteristics. This review paper also discusses various surface modification techniques for Ti-alloys to improve their biofunctions. The significance of machine learning models on advancements in developing reliable, biocompatible, personalized bioimplants and real-time quality monitoring aiding manufacturing optimization was also discussed in this paper.