Molecular Dynamics Simulations Of Friction Behaviors Of Single Crystal Zirconium

With the development of science and technology and the material performance requirements unceasing enhancement,the traditional experimental study have already can’t meet the demand of people to the study of friction and wear,so we must use numerical simulation method to study the friction and wear behavior.Especially in recent years,with the constant improvement of atomic scale theory model and the continuous improvement of computer performance,Molecular Dynamics(MD)simulation has become an important research method to study friction and wear behavior and mechanism of the material.Therefore,in this paper MD is used to simulate the friction and wear behavior of single crystal Zr(0001)surface,which is affected by various factors such as temperature(300K,400 K and 500K),friction velocity(0.1?/ps、0.2?/ps and 0.4?/ps)and load(25nN,50 nN and 100nN).By analyzing the dynamic response graph of friction and wear with displacement,the process and characteristics of friction and wear were studied.By visual software,we have analyzed the elastoplastic deformation behavior of Zr substrate during friction;the generation and distribution of grinding debris,adhesion and desorption atoms;the formation process and characteristics of dislocation loop.In order to have a deeper understanding of the friction and wear behavior of single crystal Zr,the main conclusions are as follows:(1)Temperature has little effect on the friction and wear behavior of the single crystal Zr(0001)surface,while speed and load have a significant effect on the friction and wear behavior of the single crystal Zr(0001)surface.And the smaller the speed or the larger the load,the more obvious the groove effect at the friction interface and the weaker the adhesion effect.(2)The dynamic response diagram of friction force shows that: in the initial stage of friction,the friction force increases with the increase of the displacement,and then gradually reaches a stable state.In the stable stage of friction,the friction force and the load show a proportional relationship,and the total wear and displacement and load show a proportional relationship.(3)During the friction process,the zirconium substrate undergoes complex elastoplastic deformation at the contact interface.Visualization diagram of adhesion and desorption can directly see the distribution range and density of adhesion and desorption atoms.When the speed is low or the load is large,Zirconium substrate has surface dislocation loop,which has generated along the surface and the characteristics of movement,revealing the internal stress and strain substrate in the direction of propagation.