Research On The Forming Process Of ZrO₂/Ti Biological Composites Prepared By Selective Laser Melting

Titanium alloys are widely used in orthopedics,dentistry and other medical fields because of their high specific strength,good biocompatibility and excellent corrosion resistance.The most commonly used medical material is Ti-6Al-4V,but it contains vanadium and aluminum which are harmful to human health.Therefore,it is currently preferred to use pure titanium instead of titanium alloys as medical material.However,due to the insufficient strength,low hardness and poor wear property of pure titanium,its applications are limited.In order to solve the above problems,the material properties can be improved by adding submicron zirconia reinforcement phase into pure titanium to prepare titanium matrix composites.In this paper,the ZrO₂/Ti biological composites were successfully prepared by selective laser melting?SLM?.The forming process and properties of ZrO₂/Ti composites were also studied.The main research contents are as follows:?1?The ZrO₂/Ti composite powders were prepared and the forming process of selective laser melting was studied.The results showed that the relative density of the sample increased with the increase of the laser linear energy density.When the laser linear energy density was 333.33 J/m?P=160 W,v=0.48 m/s?,the forming quality of ZrO₂/Ti composites was good,the longitudinal section of the sample was smooth,close to full density,no obvious porosity,and the relative density was as high as 99.04%.?2?The phase and the microstructure of the SLM-processed ZrO₂/Ti composites were analyzed.Under the optimized process parameters,the martensitic transformation??phase?acicular martensitic??phase?occurred in the microstructure of the SLM-processed samples.Moreover,the addition of the zirconia reinforcement phase could refine the grain of the SLM-processed samples.It was observed by SEM that the zirconia reinforcement phase with fine structure was evenly distributed in pure titanium matrix in the form of dots.?3?The effect of process parameters on the microhardness and wear property of the SLM-processed ZrO₂/Ti composites was studied.Under the process parameters used in this paper,the microhardness and wear property of the SLM-processed samples increased with the increase of the laser line energy density.?4?In order to study the effect of zirconia reinforcement phase on the properties of the SLM-processed samples,the composites samples with zirconia contents of 1wt.%,3wt.%,5wt.%and pure titanium samples were prepared by SLM.Due to the dispersion strengthening and fine grain strengthening of zirconia particles,the microhardness and compressive property of the SLM-processed ZrO₂/Ti composites were significantly improved,and increased with the increase of zirconia content.When the zirconia content was 5wt.%,the average microhardness and compressive strength of the samples were 464 HV and 1424 MPa,which were about twice that of the pure titanium samples.Due to the addition of zirconia reinforcement phase,the wear property and corrosion resistance of the ZrO₂/Ti composites were significantly improved compared with pure titanium,and gradually increased with the increase of zirconia content.?5?The porous structure of ZrO₂/Ti composites was prepared by SLM,and the biocompatibility of the ZrO₂/Ti composites was preliminarily studied.The results showed that the ZrO₂/Ti composites had good biocompatibility and no cytotoxicity.Moreover,the cell growth and adhesion on the surface of ZrO₂/Ti porous structure was better than that of pure titanium porous structure.