Atomic Simulation Based On Empirical Potential For Deformation Of Ti And TiAl Alloy Nanoparticles

Ti and its alloys have been widely applied in medical,marine,aviation,aerospace,and ground transportation because of their superior performances under using conditions.Among them,TiAl-based alloys,as an engineering material,have attracted much attentions of materials researchers and industries because of their low density,high hardness,good corrosion resistance and creep resistance.In recent decades,TiAl-based alloys have been experimentally studied to form new lightweight structural materials,and have achieved industrial applications.However,the intermetallic compound also has some defects,such as low ductility at room temperature,high yield stress at high temperature,hardly processing and forming,which hinder their applications.Forming TiAl alloy pieces by powder metallurgy technology can effectively overcome the shortcomings of casting mold and forging.High-energy ball milling can produce high-quality alloy powders.When the alloy powders are fabricated by this method,Ti or TiAl alloy particles are impacted and crushed by the grinding ball,and the particles undergo heavily plastic deformation and then are broken into small ones.This makes it be particularly important to investigate the deformation process and microstructural changes of these TiAl particles under different conditions.In this paper,the molecular dynamics method based on the embedded atom potential is used to simulate the changes in the atomic packing of Ti and TiAl nanoparticles during pressing and heating.Through analysis of the average atomic potential energy,pair distribution functions,and atomic packing structures,it is found that the atomic movements and surface structures in these particles significantly affect the deformation process of these nanoparticles,and temperatures and loading conditions strongly affects the change of atomic packing structures in these particles.During the deformation of the Ti particles,the atoms adjustment their positions.After the deformation,the rearrangements of the atoms in the particle’s surface can be observed.During the deformation of TiAl particles,the position exchanges among the Ti atoms and Al atoms and the stacking of atomic layers occur at room temperature,and rearrangements appears in the surfaces at high temperatures.When the loading is increased,the rearrangements in the surface occur at the room temperature.