Study On Forming Process And Properties Of Biomedical Titanium Alloy Fabricated By Additive Manufacturing

Ti6Al4V alloys have been widely used in medical clinical applications due to their advantages of good biocompatibility,comprehensive mechanical properties and corrosion resistance.Ti6Al4V alloy does not have antibacterial biological function,so adding appropriate amount of Cu elements with antibacterial function to medical metal can obtain antibacterial titanium alloy with good biocompatibility,mechanical properties and corrosion resistance,which has broad clinical application prospect.The traditional process of titanium alloy is complicated and the personalized processing is difficult.Selective laser melting technology provides a new idea for the processing of titanium alloy for oral cavity,and also provides an opportunity for personalized medical treatment.In this subject,Ti6Al4V-5Cu alloys were prepared by selective laser melting technology.Moreover,the process parameters and performance were optimized.The density,constituent phases,microstructure,average grain diameter,microhardness,friction and wear characteristics and electrochemical corrosion resistance of selective laser melted Ti6Al4V-5Cu alloys were systematically investigated and analyzed by high-precision analytical balance,optical microscope,X-ray diffraction,scanning electron microscope,electron backscatter diffraction,microhardness tester,multifunctional material surface performance tester and electrochemical workstation.The experimental results showed that selective laser melted Ti6Al4V-5Cu can be prepared successfully by selective laser melting technology.The optimal process parameters of selective laser melted Ti6Al4V-5Cu were scanning speed 1500mm/s,laser power 260W,spot diameter 70μm,scanning interval 45μm,layer thickness 30μm,serpentine scanning strategy.The selective laser melted Ti6Al4V-5Cu alloy had good formability,resulting in a maximum density of 99.25±0.08%.The constituent phases of selective laser melted Ti6Al4V-5Cu were composed ofα-Ti and Ti₂Cu phases.Through the EBSD analysis,the grains in the selective laser melted Ti6Al4V-5Cu alloys are in random orientation without obvious texture features.The average grain diameter of selective laser melted Ti6Al4V-5Cu alloy was smaller than that of forged TC4,which can improved the strength of materials.The highest microhardness of selective laser melted Ti6Al4V-5Cu alloys was up to 508±8HV.The wear resistance of selective laser melted Ti6Al4V-5Cu alloy in the atmospheric environment and simulated environment saliva is significantly better than that of forged TC4 specimen,and the highest can reach 4.46 and 3.37 times of forged TC4 specimen,respectively.The corrosion current density of the Ti6Al4V-5Cu alloy under optimal process parameters was 1.73×10^-8A/cm²,in the same order of magnitude as that of the forged TC4 specimen(4.23×10^-8A/cm²).The selective laser melted Ti6Al4V-5Cu alloy was equivalent to the electrochemical performance of the forged TC4 specimen,and the passivation region appeared.