Molecular Dynamics Simulation Of Formation And Control Of Diffusion Bonding Intermetallic Compounds In TiAl Alloys

The Ti Al alloy has many characteristics,such as low density,high specific strength and high specific stiffness,wear resistance,high temperature resistance,and corrosion resistance.It is,currently,widely,used,in,aerospace,,automobile,manufacturing,and other,fields,but its plasticity at room temperature is poor.It is very,easy,to,produce,welding cracks,during,welding.In addition,the welded joints are prone to deformation and hardening during the welding process.The large residual stress after welding and the faster cooling rate will make the cracking tendency greater after welding.In response to this situation,researchers have proposed to use Ti Al The alloy is plated with Ni and Al nano transition layers,and the intermediate layer adopts the diffusion bonding method of pure Ti and pure Ni foils.However,the mechanical properties of the connection joints generated by this connection method are easily affected by the Al-Ti-Ni ternary metal intermetallic.The influence of the compound.In this paper,molecular dynamics simulations of atomic diffusion and phase formation and distribution at the interface during diffusion bonding of Ti Al alloys have been carried out.The effects of temperature and pressure on the formation of phases and the motion behavior of atoms at the diffusion bonding joints of Ti Al alloy were investigated to determine the best theoretical process parameters for diffusion bonding of Ti Al alloy and to provide theoretical support for industrial production activities.The initial model of diffusion bonding of Ti Al alloy was established by means of LAMMPS molecular dynamics research software.The diffusion activities of related atoms at and near the interface were studied by means of the related molecular dynamics method.The trajectories of related atoms in diffusion bonding process and the distribution of phases in equilibrium simulation space were traced from the mechanism of molecular motion.Because the diffusion bonding process of Ti Al alloy is very fast and there are many interfaces,the diffusion process of atoms is more complicated,and it is difficult to use experimental methods to study the details of the movement of atoms at the interface.In this paper,molecular dynamics methods are used to study the influence of various process parameters on the distribution and quantity distribution of Al-Ti-Ni ternary intermetallic compounds,and to study the diffusion and phase distribution of each atom at the interface under various process parameters to compensate Insufficiency of actual experimental research methods.This article first reviews the research status of common Ti Al alloy bonding methods,then summarizes the principle and development history of molecular dynamics methods,and then constructs the initial model of Ti Al alloy diffusion bonding.After consulting related materials,the potential function in line with the subject was determined.Then I wrote the LAMMPS package of Ti Al alloy diffusion bonding,so as to carry out molecular dynamics simulation of the Ti Al alloy diffusion bonding process.