Preparation And Study On Mechanical Properties Of Porous Ti6Al4V For Medical Application

Because of its high porosity,wear resistance,good biocompatibility and mechanical properties,porous titanium alloys can be designed according to different porosity and pore size,and are applicable to various parts of human bones.They have great medical value and market potential.Common porous titanium alloy preparation methods include slurry foaming method,space holder method,additive manufacturing method and self-propagating high-temperature synthesis method.The preparation process of porous titanium alloy with simple development process,low cost,non-toxic reagent and wide porosity distribution range is of great significance for its application in the medical field.Gel-casting method is a porous metal material forming technology that can be used to prepare complex parts.However,the preparation of porous titanium alloy by gel injection molding also has the disadvantages of many reagents used,toxicity of reagents and small porosity distribution range.In this paper,the combination of gel injection molding and foaming process,using Ti6Al4V powder as raw material,using natural macromolecular agar as the gel system,the preparation process of porous Ti6Al4V alloy with adjustable porosity was studied,and its mechanical properties were studied.(1)Using agar as the gel system and hydroxypropyl methylcellulose(HPMC)as the thickening agent,the porosity can be adjusted by the process of gel-casting(porosity38%~46.1%)when porous Ti6Al4V alloy made.The effects of different process parameters such as agar content,thickener content,solids loading,gel temperature and drying temperature on the green body preparation process were studied.The influence of the porosity and pore size distribution of Ti6Al4V alloy is mainly determined by the solids loading.The study found that the optimal gel temperature of the porous Ti6Al4V wet billet is 5 ~oC,and the optimal drying temperature of the wet billet is 25 ~oC.When the solid phase volume fraction is 40%,the sintered body has a porosity of 46.1%,an elastic modulus of 35 GPa,and a small pore size,which can't meet the requirements of medical implants.(2)Through the optimization of process parameters,the gel-foaming process parameters of high-porosity(49.65%~83.1%)Ti6Al4V alloy containing a large number of large pore sizes(>100?m)were obtained,and their mechanical properties were characterized.Through element distribution and phase analysis after high temperature sintering,the formation mechanism of sinter neck and optimal sintering process of porous Ti6Al4V alloy were explored.Through process optimization,a porous Ti6Al4V alloy with good mechanical properties and better toughness was obtained.Among them,the porous Ti6Al4V alloy with a porosity of 70.53%has a compressive strength of 68.4 MPa,a compressive elastic modulus of 2.21 GPa,and good toughness.It doesn't break when it is deformed by 80%,and there is no debris during the deformation process which means it has high medical value.