An overview of surface modification, A way toward fabrication of nascent biomedical Ti–6Al–4V alloys

Titanium and its alloys are widely used in biomedical fields as metallic biomaterials, specifically for implant applications. There are many kinds of titanium alloys capable to be used in clinical treatment, Ti–6Al–4V alloys are among the most widely used biomedical implant materials due to their favorable strength, high corrosion and wear resistance along with acceptable biocompatibility. Based on the complex physiological environment in the human body and the different needs for the treatment of various diseases, the performance requirements of Ti–6Al–4V alloy are getting higher and higher. Unfortunately, Ti–6Al–4V alloy has some disadvantages like high friction coefficient, mismatch of elastic modulus, and release of cytotoxic elements, hence its original performance is not satisfactorily sufficient to meet the growing clinical requirements. In consequence, further multilateral improvement of the overall performance of Ti–6Al–4V alloy by surface modification leads to achieving more and more compatible materials with the human body environment with stable and long-term effective use. Surface modification alone is not enough for improvement of implants' efficiency and the structural influence and topological features of cellular structures should also be considered. This paper is focused on the surface modification methods for improving wear resistance, corrosion resistance, biocompatibility, antibacterial property, wettability, and elastic modulus of Ti–6Al–4V alloy with the aim to achieve high throughput nascent Ti–6Al–4V alloys for biomedical applications. It mainly focuses on the new generation of medical implants especially additively manufactured ones and it summarizes the latest articles related to Ti–6Al–4V surface modification methods and elucidates how biocompatibility improvement will be a key research direction in the field of modern Ti–6Al–4V implants in the future.