Study On Microstructure And Properties Of Ti-35Nb-7Zr-5Ta Medical Materials Fabricated By Spark Plasma Sintering

Titanium alloy has excellent mechanical properties,wear resistance and corrosion resistance.And it is currently the most widely used metal implant material.However,used titanium alloy bio-implant materials still have problems of high modulus of elasticity,poor biological activity,and some materials may release toxic elements in the human body.The elastic modulus of the material was lowered by the addition of the pore former NH₄HCO₃.The bioactivity of the material is increased by alkali treatment or addition of HA.In this paper,various Ti-35Nb-7Zr-5Ta implant materials were prepared by SPS,and the relative density,microstructure,elastic modulus,compressive strength and biological activity of the materials were studied.The relative density of Ti-35Nb-7Zr-5Ta alloy increases with the increase of sintering temperature.Titanium alloys are composed of?-Ti and a small amount of?-Ti,Nb,and Ta phases.As the sintering temperature increases,the element diffusion becomes more uniform,and the?-Ti phase increases,and the?-Ti,Nb,and Ta phases decrease.As the sintering temperature increases,the elastic modulus of the material rises from 43GPa to 53GPa,which is higher than that of human bone.Its compressive strength increased from 1563MPa to1777MPa.The titanium alloy exhibited bio-inertness in SBF.However,the surface of the titanium alloy treated with different concentrations of NaOH showed good biological properties,and the titanium alloy treated with 10 mol/L NaOH had the best biological activity.The relative density of?Ti-35Nb-7Zr-5Ta?-HA composites increases with the increase of sintering temperature and decreases with the increase of HA content.The phases of the composite are composed of?-Ti,?-Ti and newly formed ceramic phases Ti₂O,Ca₃?PO₄?₂,CaZrO₃,CaO and Ti₅P₃.The elastic modulus of the composite varies from 30-95GPa,slightly higher than human bone.Its compressive strength varies between 593-1978MPa to match the implantation requirements.The composites to which HA is added are biological activity.With the increase of sintering temperature,the biological activity gradually decreased,and with the increase of HA content,the biological activity gradually increased.The mechanical properties and biological activity of the 15wt.%HA composite at 950°C are suitable for the requirements of implant materials.The open porosity of porous Ti-35Nb-7Zr-5Ta alloy decreases with the increase of sintering temperature,and the open porosity increases with the increase of NH₄HCO₃content.The porous structure is mainly formed by the macropores left by the decomposition of NH₄HCO₃ and the pores left by the incomplete sintering.The phases of the porous titanium alloy are all composed of?-Ti,?-Ti,Nb,and Ta.The elastic modulus of porous titanium alloy can be regulated in the range of 1.1-6.0GPa,which is consistent with human bone.However,its compressive strength varies from 32MPa to 160MPa,slightly lower than human bone.The porous titanium alloy exhibited biological inertness after soaking in SBF.The surface of the titanium alloy treated with different concentrations of NaOH exhibited high bioactivity,and the surface of the titanium alloy treated with 10 mol/L NaOH formed a multi-layered bone-like apatite.The density of porous?Ti-35Nb-7Zr-5Ta?-HA composites decreased with the increase of NH₄HCO₃ content,and the density increased with the increase of HA content.The phases of the material are composed of?-Ti,?-Ti and newly formed ceramic phases Ti₂O,CaZrO₃,CaO,Ti₅P₃.The elastic modulus of the porous composite varies from 12GPa to 52GPa.The compressive strength of this material varies from 255-1696MPa.Therefore,porous composite biomaterials have good mechanical compatibility.Therefore,the porous composite material has excellent mechanical compatibility.The composites added with HA are biologically active.As the content of NH₄HCO₃ and HA increases,the biological activity gradually increases.However,biological activity is not as good as alkali treatment and needs to be further improved.In summary,the porous?Ti-35Nb-7Zr-5Ta?-HA composite prepared by SPS technology has mechanical properties suitable for human body and has good biological activity.It is a bio-implant material with excellent comprehensive performance and has potential application value.