Phase Equilibrium Experimental Determination And Thermodynamic Calculation Of Ti-Zr-X(Ta,Nb,Ni) Biomedical Titanium Alloy

Titanium and titanium alloys have been widely used in the field of biomedical materials due to their low density,high strength,low modulus of elasticity,good corrosion resistance and good biocompatibility.Among them,the new ?-titanium alloy has become a hot spot,and the research on non-toxic ?-titanium alloy and medical shape memory alloy has become a hot spot.As an important theoretical basis for material design,phase diagram plays an important role in material composition design and process optimization.Therefore,the experimental determination and thermodynamic calculation of biomedical titanium alloy system and the establishment of thermodynamic database of biomedical titanium alloy system have important theoretical value and economic value for realizing the precise design and process optimization of biomedical titanium alloy composition and structure.In this thesis,the thermodynamic calculation and experimental verification of some biomedical titanium alloy systems are carried out by experimental determination and thermodynamic calculation.The results are as follows:The thermodynamic information of Ti-Zr,Ti-Nb,Ti-Ta,Zr-Nb and Zr-Ta systems were collected and combined with the thermodynamic information of three marginal binary systems and Ti-Zr-Nb and Ti-Zr-Ta,the thermodynamic calculation and optimization of Ti-Zr-Nb and Ti-Zr-Ta ternary systems were carried out by CALPHAD technique,and a ternary phase diagram with certain predictive properties was obtained.The isothermal section of Ti-Zr-Nb at 700 ? and 800 ? was experimentally determined by alloy method,X-ray diffraction analysis technique,metallographic microscope,scanning electron microscope and spectrometer,and electron probe microarea method(EPMA).Phase diagram and isothermal cross-section diagram of Ti-ZrTa at 900 ?,1000 ?,1100 ?,verify the extrapolation prediction ternary phase diagram,and then based on the experimental data of this study,Ti-Zr-Nb and Ti-Zr-Ta ternary system for further optimization and correction,obtaining a set of self-consistent thermodynamic parametersThe system collects,organizes and evaluates the existing thermodynamic properties and phase diagram experimental data of Ti-Zr-Ni,selects a reasonable thermodynamic model for description,and based on the experimental data of the latest high temperature part,uses CALPHAD technology to the Ti-Zr-Ni ternary system.Phase equilibrium for thermodynamic calculation and optimization,resulting in a set of self-consistent thermodynamic parametersBased on the experimental results and optimization calculation results of this study,combined with the experimental and calculated data reported in the previous literature,the Ti-Zr-based biomedical titanium alloy database was initially established.The phase equilibrium experimental results obtained in this study and the thermodynamic parameters obtained by calculation and optimization will be an important part of the biomedical titanium alloy database.At the same time,the research results will also provide the composition design and process optimization of biomedical titanium alloy.Important theoretical guidance.