Molecular Dynamics Simulations Of The Characteristics Of Mo-Ti Interfaces

Mo and Mo-based alloys have been widely used in electrical and electronic equipment manufacturing,metal materials processing industry,aerospace and defense industry applications due to their thermal conductivity,electrical conductivity and high temperature strength.The applications of Mo and Mo-based alloys in the above fields mainly adopt the methods of metal processing and welding.Since the melting point of metal Mo is relatively high,it is usual to add Ti as intermediate metal with relatively low melting point to achieve the connection by diffusion between the intermediate metal and the base metal.The diffusion mechanism of Mo-Ti on the interface has not been clear up to now and needs to be explored.As is known to all,MD simulations provide a useful tool for a detailed understanding of the underlying mechanisms at atomistic scales.However,the reliability of the MD simulations of Mo-Ti interface is mainly dependent on the accuracy of the interaction potentials between Mo and Ti.In order to solve this problem,new analytical interatomic potentials have been developed firstly.Based on those potentials,the diffusion bonding of Mo-Ti interface has been investigated.We construct the element potential of Mo and Ti and the potential of Mo-Ti alloy,and verify the validity of the potential by reproducing the mechanical properties such as mechanical properties and thermodynamic properties.Based on these potential functions,the evolution of Mo-Ti interface diffusion with time is studied.By careful analysis,it is found that the longer the diffusion time is,the more obvious the diffusion is.In addition,the effect of temperature on diffusion is studied,the higher the temperature,the wider the interface area.When the temperature is 900K,only a small amount of atoms diffuse into each other interface,and the interfacial structure does not change obviously.As the temperature increases,the number of interdiffusion atoms increases gradually.When the temperature reaches 1100K,the interface area appears disorder structure.Besides,it is found that the diffusion of Mo atoms and Ti atoms at the interface exists asymmetric,and the Mo atoms are far more than Ti atoms in the diffusion number and diffusion depth.Finally,the influence of the interface orientation on the diffusion is studied.Study on three different surfaces of Mo substrate,namely(100)plane,(110)plane and(111)plane.By comparing the diffusion depth of different surfaces and the number of diffusion atoms,it is found that(111)plane is more easily diffused than(100)plane and(110)plane.The main reason is that the surface energy of the(111)plane is higher than that of the(100)plane and the(110)plane,the(111)plane has a lower surface density than the(100)plane and the(110)plane and(111)plane is rough surface.