Microstructure and biocompatibility of porous-Ta/Ti-6Al-4 V component produced by laser powder bed fusion for orthopedic implants

Abstract

Tantalum is attracting more attention as an outstanding orthopedic implant material due to its excellent corrosion resistance and biocompatibility. However, the high melting point and strong oxygen affinity of tantalum make its preparation more difficult and costly. In addition, the high cost of raw materials also limits the wider application of tantalum. To break these limitations, porous tantalum coatings with different pore sizes were successfully prepared on Ti-6Al-4 V base by Laser Powder Bed Fusion, constructing an integral porous-Ta/Ti-6Al-4 V component with excellent bioactivity and osteointegration capacity. A strong metallurgical bonding was formed between tantalum and Ti-6Al-4V, and the bonding strength is more than 460 MPa. The porous tantalum coating is designed as diamond-like structure with strong symmetry. The porosity of tantalum coatings is 70%, and the pore size ranges from 447 to 865 μm. Its deformation characteristics are extremely similar to those of natural cancellous bone. The average compressive yield strength of the porous Ta coatings ranges from 5.8 to 24. 2 MPa. And the average compressive elastic modulus of porous Ta coatings (0.6–1.5 GPa) was close to that of cancellous bone. Corrosion resistance tests proved that the Ta-coated Ti-6Al-4 V alloy had an excellent chemical stability in simulated body fluid. In vitro tests showed that Mouse calvarial preosteoblasts presented a good adhesion and growth behavior on porous Ta coatings. Therefore, it is preliminarily determined that the customized porous-Ta/Ti-6Al-4 V component by Laser powder bed fusion can be a candidate material for orthopedic implantation. • A novel high-interface-strength porous Ta/Ti6Al4V component was successfully manufactured using Laser Powder Bed Fusion. • The mechanical properties of the component met the requirements of ideal orthopedic implant materials. • The component had a good chemical stability and an excellent biocompatibility in simulated body fluid.