Atomic Scale Calculation Of Defect Behavior Of Ti-Al System Intermetallic Compounds

With the progress of social science and technology,the research on metal properties is more in-depth.Due to the different degree of metal defects in the production and processing,and defects have a significant impact on the mechanical properties of materials.After continuous exploration,it has been found that Ti-Al intermetallic compounds have excellent mechanical properties and high temperature resistance.Therefore,it is of great significance to study the microstructure defects of metal during fatigue deformation.This paper,the method of kinetic simulation is used to study the elements and compounds from two perspectives.One is to select different potentials to study the point defect properties,the other is to study the deformation defects of Ti and Ti Al.In this paper,the vacancy energy of crystal is firstly calculated by three kinds of interatomic potentials.One is the interatomic potentials developed by our group,which are the interatomic potentials of Ti,Al and Nb elemental materials,and the interatomic potentials of Ti-Al binary intermetallic compounds and Ti₂Al Nb ternary intermetallic compounds.The second is Mendelev and Ackland's interatomic potential of elemental Ti.The third is the interatomic potential of Zope and Mishin.The performance of atomic point defects was simulated by LAMMPS software,and the calculated results were in good agreement with the existing theoretical and experimental values.Through calculation,it is concluded that the Ti elemental substance calculated by this group of potential is closer to the experimental value.Comparing the vacancy energy and anti-vacancy energy of different Ti Al structures,it is found that?-Ti Al is easy to form Al vacancy,but when calculating the D0₁₉Ti Al structure,it is found that the anti-vacancy energy is low,so the formation of anti-vacancy is easier.When calculating Ti₂Al Nb,it is concluded that the vacancy formation energy of Ti and Al is lower than that of anti-vacancy formation energy,so it is easier to form Ti and Al vacancies.At the same time,the potential of Ti element developed by our group was used to load the HCP structure titanium in different directions,and the deformation behavior was observed through molecular dynamics simulation and visualization software Ovito to explore the stress and strain at different deformation degrees.Observed the defects generated at atomic scale and the direction of movement of the defects,and compared the deformation generated by loading Ti in different directions.It is concluded that the trend of stress variation in tension and compression is not symmetrical.In addition,the mechanical evaluation of three typical interfaces of Ti Al is carried out with the potential developed in this group.It is concluded that ODB is superior to TB and PTB in plasticity.