Basic Theoretical Research On The Microstructure Of Ti-Al-V Alloy

Ti-Al-V alloy is widely used in various fields because of its characteristics of high strength,good corrosion resistance and high heat resistance.Many countries in the world have realized the importance of titanium alloy materials,which have been studied and developed in succession,and have been applied in practice.However,due to the large difference between the melting points of metal Al and Ti of the base metal in Ti-Al-V alloy,Al element is easy to volatilize during the smelting of Ti-Al-V alloy,resulting in the alloy composition is not easy to control.In order to explore the mechanism of this process,it is necessary to study the microstructure of Ti-Al-V alloy.Nowadays,the theoretical design of molecules and materials by combining theoretical calculation with experimental research in a certain range has gradually become a common research method in the fields of metallurgy,biology and materials.Therefore,the microstructure and component interaction mechanism of Ti-Al-V alloy were studied by the first-principles method.The main contents of this paper are as follows:the ground state structure of Al_nV_n(n=2-12),Al_nTi_n(n=2-12)and V_nTi_n(n=2-12)clusters are searched by ab initio molecular dynamics,and the average binding energy,vertical electron ionization potential,vertical electron affinity potential,HOMO-LUMO gap and PDOS(Partial Density of States)of Al_nV_n(n=2-12),Al_nTi_n(n=2-12)and V_nTi_n(n=2-12)clusters are calculated based on density functional theory.The properties of the melt structure of Ti-Al-V alloy were calculated.The results are as follows:(1)The evolution law of Al_nV_n(n=2-12),Al_nTi_n(n=2-12)and V_nTi_n(n=2-12)binary alloy clusters and Ti-Al-V ternary melt structure were revealed from the atomic level.In Al_nV_n(n=2-12)and Al_nTi_n(n=2-12)binary alloy clusters and Ti-Al-V ternary melt structure,the trend of the visible nuclei of V and Ti atoms.This is consistent with the poor solubility between Al and Ti-V in the experiment.(2)Based on the analysis of the relative stability of Al_nV_n(n=2-12),Al_nTi_n(n=2-12)and V_nTi_n(n=2-12)binary alloy clusters,it is found that the average binding energy of clusters tends to increase with the increase of cluster size n value,and the variation trend is gradually weakened.In general,when the binding energy tends to be stable,Al_nV_n(n=2-12),Al_nTi_n(n=2-12)and V_nTi_n(n=2-12)clusters can be used as candidates for calculating the interaction energy parameters of Al-V,Al-Ti and V-Ti alloy.(3)By studying the electronic properties of Al_nV_n(n=2-12),Al_nTi_n(n=2-12)and V_nTi_n(n=2-12)binary alloy clusters,it is found that the vertical electron ionization potential(VIP)of clusters decreases gradually with the increase of cluster size n value,while their corresponding vertical electron affinity potential(VEA)shows the opposite trend.Combined with the decrease of HOMO-LUMO energy gap with the increase of cluster size and the continuous increase of PDOS(Partial Density of States)continuity,it can be concluded that the electron mobility of clusters is gradually increased,that is,the metallic property of clusters is enhanced.