Bioactive and fatigue-resistant Ti–Ta alloy by additive manufacturing for orthopedic applications

Abstract

Despite advancements, metallic materials for load-bearing medical applications still face ongoing challenges. Titanium (Ti) and tantalum (Ta) are widely used due to their mechanical and biological properties, but both have limitations: Ta is highly bioactive but heavy and expensive, while Ti is lightweight but less bioactive. Metal additive manufacturing (AM) offers a new pathway for the design of porous metallic biomaterials. This study developed a 50 wt% Ti–Ta alloy for orthopedic implants using in situ alloying capability from laser powder bed fusion (LPBF) AM to combine Ti's lightweight with Ta's bioactivity. Extensive evaluations, including fatigue testing, wettability analysis, and in vitro and in vivo biocompatibility assessments, revealed the superior fatigue and biocompatibility performance of LPBF-fabricated Ti–Ta alloys compared to pure Ti. The alloy demonstrated exceptional fatigue resistance, enduring up to 10 5 cycles at 110 % of yield strength, and achieved a 40 % bone–implant contact rate 12 weeks after implantation in rabbit femurs. For the first time, this study uncovered the critical influence of LPBF process parameters (i.e., laser power and scan speed) on the microstructures, mechanical properties, and biocompatibility of Ti–Ta alloys. These findings validate LPBF's capability to produce bioactive, mechanically robust Ti–Ta scaffolds, underscoring their potential for advanced orthopedic applications. • LPBF in-situ alloying is effective for fabricating Ti-Ta alloy for orthopedic application. • Microstructure and properties of Ti-Ta alloys can be tailored via LPBF processing parameters. • Optimized LPBF parameters yield Ti-Ta alloys with fatigue resistance comparable to Ta and superior to Ti. • Ti-Ta alloys produced under optimal LPBF conditions exhibit biocompatibility matching Ta and exceeding Ti.