Superior corrosion resistance and good biocompatibility of Ti-24Nb-4Zr- 8Sn alloy fabricated by a cost-effective, net-shape powder metallurgy method

Non-toxic β-type titanium alloy is expected to be a next-generation biomaterial due to the low Young’s Modulus and good biocompatibility. Reducing costs and fabricating complex parts of titanium alloys are essential considerations for biomedical applications, which, however, do not usually work for both simultaneously. Here, we have successfully fabricated Ti-24Nb-4Zr-8Sn (Ti2448) alloys with low Young’s Modulus, superior corrosion resistance, and good biocompatibility via a cost-effective, net-shape powder metallurgy method. The corrosion rate of the Ti2448 alloy, treated with hot isostatic processing and water quenching (SHIPQ), is more than 3.5 times lower than that of the Ti-6Al-4V (Ti64) counterpart. This substantial reduction is primarily attributed to the lack of galvanic corrosion in a single β phase, as there is a lack of driving force (potential difference), and most pores are eliminated during hot isostatic processing. Furthermore, compared with the Ti64 counterpart, the SHIPQ alloy exhibited increased lamellipodia spread, with pronounced filamentous filopodia extending from the leading edge of the lamellipodia and the cellular body in MG-63 cell culturing. It also showed a greater volume of new bone and higher mineral density around the implants, with no detectable inflammatory response in the micro-computed tomography (micro-CT) or Haematoxylin and eosin (HE) staining results of removed femoral implants, suggesting that the SHIPQ alloy is biocompatible. Besides, as an implant in long-term service, SHIPQ alloy has distinct advantages because of its low Young’s modulus and lack of allergic or toxic elements, showing great potential for future clinical applications.