Microstructure and Mechanical Properties of Ti–Ta Composites Prepared Through Cold Spray Additive Manufacturing

In this study, an innovative approach was used to fabricate Ti–Ta composite biomaterials through cold spray additive manufacturing followed by a diffusion treatment. The microstructure and mechanical properties of the composites were investigated in detail using field emission scanning electron microscopy, electron backscatter diffraction, 3D X-ray computed tomography, tensile test, nanohardness test and resonance vibration test. The obtained results indicated that the prepared composites have inhomogeneity in their microstructure and composition. A unique microstructure, composed of Ti-rich, Ta-rich and diffusion regions, was evolved in the composites due to incomplete diffusion between Ti and Ta splats. Further, Kirkendall pores were formed in the composites due to uneven diffusion of the two phases (of Ti and Ta) during high-temperature heat treatment. The prepared composites simultaneously showed low elastic modulus and high tensile strength which is required for a good biomaterial. Low elastic modulus was associated with the residual pores and the alloying effect of Ta in Ti, while high tensile strength was related to the solid solution strengthening effects. The obtained results indicated that the prepared Ti–Ta composites have a great potential to become a new candidate for biomedical applications.