Microstructure And Mechanical Properties Of Ti6Al4V Artificial Hip Joint Manufactured By Electron Beam Melting

Titanium and titanium alloys have been widely used in the medical field due to their excellent corrosion resistance,biocompatibility,mechanical properties and processing properties.Additive manufacturing technology has attracted more and more attention academically and clinically as it can be used to fabricate customized implants.However,the existence of defects such as holes and the anisotropic microstructure significantly affect the mechanical properties of 3D printed titanium alloy.In addition,effects of different heat treatments on the microstructure and properties of 3D printed titanium alloy have not been systematically studied.In this study,the defects,microstructure and mechanical properties of Ti6Al4 V titanium alloy manufactured by electron beam melting in the transverse section and longitudinal section were studied.The effects of different heat treatments on the microstructure and properties of the EBMbuilt Ti6Al4 V were mainly investigated.It was found that the EBM titanium alloy has obvious anisotropic microstructure on the transverse section and longitudinal section.Tensile test results showed that the strength of transverse specimens is higher and the plasticity of longitudinal specimens is better.This experiment also explored the changes in the microstructure and mechanical properties of the EBM-built Ti6Al4 V alloy after it was preserved at 900 ?,1000 ? and 1100 ? for one hour,followed by air cooling(AC).It was found that after heat treatments of 9000 ? / 60 min / AC,1000 ? / 60 min / AC and 1100 ? / 60 min / AC,the grain size increases from 102.45 ?m to 122.73 ?m,209.34 ?m and 509.67 ?m respectively.The X-ray diffraction found a peak of ?-phase(110)indicating an increase in the concent of ?-phase after heat treatments.The shift of peak position illustrated an increase in the solid solubility of solute elements in the heat-treated alloy.The tensile test results showed that tensile strength decreases by 4.92 %,4.72 % and 5.62 % and the yield strength decreases by 6.97 %,5.7 % and 7.1 % respectively after heat treatments of 900 ? / 60 min / AC,1000 ? / 60 min / AC and 1000 ? / 60 min / AC.