High Temperature Solid Carburizing And Biotribological Properties Of Ti15Mo Alloy

Beta type Ti15 Mo alloy has the advantages of low elastic modulus,good corrosion resistance and good biocompatibility,which is regarded as one of the potential biomedical materials.However,due to the poor hardness and wear resistance of titanium alloy,it faces the risk of debris disease caused by wear in clinical application,which limits its further development in the medical field.Carbon atoms easily enter the surface of titanium alloy due to diffusion and form titanium carbide under high temperature.Graphene and carbon nanotubes as carbon family members have long been proved to have excellent biological properties.Therefore,in this paper,carbon powder,graphene and multi-walled carbon nanotubes were selected as carburizing agents,and the surface modification of Ti15 Mo alloy was carried out by high-temperature solid carburizing technology.The surface composition,mechanical properties,surface morphology,biotribological properties,electrochemical properties and surface wettability of carburized titanium alloy were tested.Therefore,It was found that the depth of Ti C cementite layer on the surface of CP-Ti15 Mo,G-Ti15 Mo and MWCNTs-Ti15 Mo alloys increased with temperature.The maximum infiltration depth can reach 92.05 ?m,184.02 ?m and 1433.68 ?m respectively.The highest hardness can reach 1117.4 HV,1221.5 HV and 1246.1 HV,respectively,which are 3.60,3.93 and 4.01 times of the microhardness of Ti15 Mo alloy.The surface morphology of CP-Ti15 Mo alloy gradually presents spherical distribution with the increase of temperature;The surface morphology of G-Ti15 Mo alloy shows plate-like distribution with increasing temperature,and more pores appear.The surface morphology of MWCNTs-Ti15 Mo alloy gradually exhibits lath-like distribution with the increase of temperature.The friction coefficient and wear rate of Ti15 Mo alloy under different carburizing conditions decreased in SBF simulated body fluid and 25% calf serum solution.In SBF simulated body fluid,the wear rates of CP-Ti15 Mo,G-Ti15 Mo and MWCNTs-Ti15 Mo alloys could be reduced to 58.26%,74.24% and 77.22% of the original samples of Ti15 Mo alloy,respectively.In 25% calf serum solution,the wear rates can be reduced to 47.93%,68.83% and 82.06% of the original samples of Ti15 Mo alloy,respectively,and the wear resistance of the material is greatly improved.The electrochemical corrosion depth of carburized Ti15 Mo alloy decreases,and the corrosion resistance grade increases by 1?2 grade,which meets the requirements of human implantation.The contact angle decreases,the adhesion work increases,the wettability and surface free energy are greatly improved,which is beneficial to cell adsorption and improve the biocompatibility of the material.This paper has 57 figures,14 tables and 94 references.