Study On Technology And Properties Of Ti12Mo6Zr2Fe Alloy By Selective Laser Melting

Biomedical titanium alloy has a wide range of medical applications because of its superior biocompatibility,excellent mechanical properties and low elastic modulus close to human compact bone.Ti-12Mo-6Zr-2Fe(TMZF)alloy is a metastable?-Ti alloy with high strength,low elastic modulus,superior corrosion resistance and wear resistance,which is an ideal artificial bone implant biological material.Therefore,it has been approved to utilize in the clinical medicine field.In this present work,the metastable?-Ti alloy Ti-12Mo-6Zr-2Fe(TMZF)was successfully fabricated by SLM technology with pre-mixed powders.Firstly,single track forming of SLM TMZF was simulated by ANSYS software,and the single track samples were prepared by SLM technology for verification.The forming quality,melting width,melting depth,melting height and element distribution of the single track section of SLM TMZF single track samples were systematically studied.In the single track forming process of TMZF,the temperature field gradually decreased from the laser irradiation point to the surrounding.With the increase of linear energy density,the melting width increased,and the flatness and continuity of a single track became better.At high energy density,the surface of the single track was smooth,the cross section of the single track was arc-shaped,the element distribution in the single track was uniform,and there was a small amount of unmelted titanium powders.Secondly,SLM parameters were optimized by response surface method and low-power parameters verification.Through comprehensive comparative analysis,the optimal parameters of SLM TMZF were determined as(100 W,500 mm/s,0.1 mm).Under the optimal parameters,the phase of SLM TMZF sample was all?-Ti,the grain size of the sample was relatively small,the preferred orientation of the sample grain was<101>direction,and there was segregation in the distribution of elements in and between grains.Finally,TMZF samples(100 W,500 mm/s,0.1 mm)were prepared by SLM under the optimal parameters.The nano indentation,wear resistance,biocompatibility and electrochemical corrosion behavior of SLM TMZF in 3.5 wt.%Na Cl solution were systematically studied.The average microhardness and elastic modulus of SLM TMZF were442.1 HV_0.2 and 130.94 GPa respectively.The friction and wear test in 3.5 wt.%Na Cl solution had been done and the average wear rate of SLM TMZF sample was 13.24×10^-5mm³/(N·m),and the average wear rate of the TMZF cast sample was 40.69×10^-5 mm³/(N·m),the friction and wear performance of SLM TMZF sample in 3.5 wt.%Na Cl solution was better.This indicated that SLM TMZF sample has good biocompatibility.The electrochemical performance test in 3.5 wt.%Na Cl solution,the I_corr of the TMZF casting and SLM TMZF sample were 0.32?A.cm^-2 and 1.07?A.cm^-2;TMZF casting sample showed higher impedance than SLM TMZF sample;the capacitive arc radius of the SLM TMZF specimen was smaller than that of the TMZF casting specimen.Therefore,in 3.50 wt.%Na Cl solution,the corrosion resistance of the TMZF casting sample was better than that of SLM TMZF sample.