The Solid Carburization Of Ti6Al4V In High Temperature And Its Properties Study

Due to good corrosion resistance, biocompatibility, high mechanical strength and good processing performance, Ti6Al4 V, namely TC4 alloy, has been widely applied in the field of orthopaedic survey. However, the poor tribological of TC4 greatly limits it’s further widely used in artificial joints. In order to develop high-performance artificial metal joints, many researches about surface modification have been taken to prepare ceramic layers with high hardness and good corrosion resistance, and then study its biological tribology performance under many different conditions, which is of great significance for the titanium alloys used as medical material.In this paper, solid carburizing agent was used to prepare a highly hard carburized layer on the surface of TC4, effectively avoid hydrogen embrittlement phenomenon in the traditional ion implantation process. In this paper, many characterizations, like surface morphology, composition, corrosion resistance and tribology performance, were taken to analyze the effect of carburizing technology on these properties of ceramic layer.Surface morphology analysis showed that the original surface morphology of sample had great change after carburizing, on which stacking large numbers of dense particles and club-shaped carburizing product, which’s surface boning force was little and easy to peel. At the high temperature, the longer the time of heat preservation, the more bulky the Ti C particles. When carburizing time was long enough, the soaking time had little effect on particles’ size. After simply polishing, a large quantity of pores prepared by Ti C particles stacking with different orientations, exited on the sample’s surface. Secondary Ti C grains existed in these pores. A thin and porous titanium oxide layer was formed on the surface of samples, and there was a small amount of Ti C and Ti N. The existence of Ti O2 did not hinder the penetration and diffusion of carbon atoms in the matrix, and had little influence on the carburizing process. After removing the original surface, the main ingredient was Ti C. The higher the carburizing temperature, the ceramic layer was thicker. The longer of soaking time, the ceramic layer was thicker. The sample’s surface hardness increased significantly after carburizing, and the maximum hardness could be up 4 times more than that of original sample.The corrosion resistance degenerates under saline, 5wt% H2SO4 and SBF solution after carburizing, but the samples were still belong to the corrosion resistance material. The surface wettability increased, and it could effectively improve the biocompatibility of Ti6Al4 V and be good for the adsorption of cells.The friction of carburized samples did have no large different from that of Ti6Al4 V. However, with the hardness improved significantly, the wear rate in three kinds of lubricant was apparently lower than that of Ti6Al4 V matrix. The surface modification of the surface solid carburization can greatly improve the wear resistance under different state.