A novel in-situ synthesized bioactive TaZrTi alloy by high energy laser beam for total knee arthroplasty application

Abstract

Total knee arthroplasty is the gold standard treatment for end-stage knee osteoarthritis, which could significantly improve function and relieve pain for patients. However, the present materials and manufacturing approaches are dissatisfactory for knee implants. In the present work, a Ta60-Zr20-Ti20 (in wt%) coating was in-situ synthesized onto Ti6Al4V alloy via a high energy laser beam. The microstructure analysis indicated that α-Ta/ZrTi solid solution generated into body-centered cubic (bcc) grains in dimensions of several to hundred micrometers. The Ta-riched dendrites nucleated, grew, and expanded in the ZrTi matrix. The mechanical and biological properties of the in-situ synthesized TaZrTi sample are compared with the conventionally rolled Ti6Al4V, which is also the substrate alloy. The mean values of hardness and elastic modulus of in-situ synthesized TaZrTi tested by the nanoindenter, are 10.31 and 134.84 GPa, respectively. These results are harder than the Ti6Al4V counterpart (5.14 GPa) with a preferred slightly low elastic modulus (152.95 GPa of Ti6Al4V). Subsequently, the in-situ synthesized TaZrTi exhibits an excellent wear resistance demonstrated by nano-scratch experiments. In addition, the osteoblastic and endothelial cells were cultured in vitro to evaluate the biocompatibility of in-situ synthesized TaZrTi. The results show a comparable bioactivity and surface affinity compared with the rolled Ti6Al4V in 7 days. Briefly, this in-situ synthesized TaZrTi alloy is expected to shed light on load-bearing orthopedic applications to relieve the pain of patients, and the findings in this study provide an insightful understanding of laser additive manufactured TaZrTi alloy.