Study On The Properties And Bone Implantation Simulation Of TiZrNb Medium Entropy Alloys For Biomedical Applications

High Entropy Alloys（HEAs）have changed people’s traditional cognition of metal materials due to their unique properties such as high strength,high toughness,high hardness,excellent low temperature toughness,excellent corrosion resistance and radiation resistance.In recent years,Medium Entropy Alloys（MEAs）derived from this have attracted extensive attention from researchers.Among them,titanium-based BCC refractory medium/high-entropy alloys have outstanding performance in mechanical properties,corrosion resistance and friction resistance,and have become one of the research hotspots in the field of biomedical alloys.In this paper,by adjusting the valence electron concentration value of the alloy,the biomedical non-equiatomic TiZrNb Hf Mo and TiZrNb Hf Ta medium entropy alloys with low elastic modulus,high strength and high corrosion resistance were designed and prepared,and the bone implantation simulation was carried out by ANSYS Workbench.It was found that the alloy had good bone adaptation.The experimental results obtained in this paper are as follows:In this paper,Ti₄₅Zr₄₅-Nb Hf Mo and Ti₄₅Zr₄₅-Nb Hf Ta medium entropy alloys satisfying the empirical criterion parameters were designed and prepared.Combined with Thermo-Calc thermodynamic calculation,it is predicted that the alloy formation phase is BCC solid solution structure.XRD,OM and SEM analysis also confirmed that the entropy alloys in the two groups were single-phase BCC structure and dendritic morphology.EDS results show that Ti and Zr are slightly segregated in the interdendritic region,while Hf,Nb,Mo and Ta are mainly enriched in dendrites.In this paper,Ti₄₅Zr₄₅-Nb Hf Mo and Ti₄₅Zr₄₅-Nb Hf Ta medium entropy alloys satisfying the empirical criterion parameters were designed and prepared.Combined with Thermo-Calc thermodynamic calculation,it is predicted that the alloy formation phase is BCC solid solution structure.XRD,OM and SEM analysis also confirmed that the entropy alloys in the two groups were single-phase BCC structure and dendritic morphology.EDS results show that Ti and Zr are slightly segregated in the interdendritic region,while Hf,Nb,Mo and Ta are mainly enriched in dendrites.Secondly,the mechanical properties,corrosion behavior and wear resistance of Ti₄₅Zr₄₅-Nb Hf Mo and Ti₄₅Zr₄₅-Nb Hf Ta medium entropy alloys were characterized.The results show that with the increase of Mo and Ta content,the yield strength of the alloy is significantly improved due to the solid solution strengthening caused by modulus mismatch.The tensile yield strength of Ti₄₅Zr₄₅Nb₃Hf_3.5Mo_3.5 medium entropy alloy reaches 927±5 MPa.The elastic modulus of the alloy is between 48 GPa and 59 GPa,which is much lower than that of Ti6Al4V alloy（110 GPa）.With the increase of Mo and Ta elements,the fracture mode gradually changes from ductile fracture to brittle fracture.No pitting corrosion occurred in the two alloys in PBS solution,and they had better corrosion resistance than Ti6Al4V.In addition,with the increase of alloy hardness,the average friction coefficient and wear area are also decreasing.According to the wear morphology and wear debris composition,the wear mechanism medium entropy alloys is abrasive wear and corrosion wear.Finally,the contact mechanics model of artificial hip joint and the model of prosthesis implantation were established,and the maximum joint force during human walking was applied.The Ti₄₅Zr₄₅Nb₇Hf_1.5Ta_1.5 medium-entropy alloy（48 GPa）with the lowest elastic modulus was selected as the prosthesis material for contact stress simulation and prosthesis implantation simulation.The contact stress simulation results showed that the peak contact stress caused by the medium-entropy alloy as the femoral head material to the Co Cr Mo liner was the smallest in the metal-metal contact pair.The simulation results of prosthesis implantation showed that compared with Ti6Al4V,the femoral stem material significantly reduced the effect of’stress shielding effect’on the femur after implantation.In summary,two groups of TiZrNb medium entropy alloys with high strength,near-bone elastic modulus and excellent corrosion resistance were developed in this paper.Secondly,the relationship between alloy composition,microstructure and comprehensive properties（mechanical properties,corrosion resistance,friction properties）was explored.Finally,finite element simulation proves that TiZrNb medium entropy alloys can significantly reduce the“stress shielding effect”as a hip prosthesis material.This paper provides a theoretical basis for the study of implant materials and explores the possibility of the application of medium entropy alloys in the biomedical field.