Microstructure and mechanical properties of SiC whiskers modified Ti-39Nb alloy fabricated by laser powder bed fusion

Titanium-niobium alloys have great potential in biomedical implants due to their low elastic moduli, excellent corrosion resistance, and biocompatibility. However, the strength of Ti-Nb (TN) alloy is still limited due to the almost n-Ti phase, leading to the limited strengthening effects. In this study, SiC whiskers modified (Ti39Nb)99.5SiC0.5 (TNS) alloy with low elastic modulus were fabricated by laser powder bed fusion (LPBF). TN alloy mainly comprises n-Ti phase, while TNS alloy contains n-Ti, alpha-Ti, SiC, Ti5Si3, Si, and omega phases. Si-rich phase was distributed uniformly in the n-Ti matrix with dots inside grains and networks along the grain boundaries. Compared with TN alloy, the yield strength of TNS alloy increased from -680 MPa to -816 MPa corresponding to the sacrifice of elongation from -17.3 % to -9.2 %. The contribution of the strengthening mechanisms was investigated. The SiC addition substantially increased the wear resistance two times with a low wear rate of 0.756 x 10-3 mm3/N center dot m. These results provide a guide for the design of n-type Ti alloys with high strength and low modulus.