Atomic Diffusion Behavior Near The Bonding Interface During The Explosive Welding Process

With the research and development of composite material,the problems between high-performance materials and material cost have been successfully solved.Explosive welding is an effective technology to produce composite plates without producing an obvious heat-affected zone.It is always a controversial topic whether there is obvious atomic inter-diffusion near the interface during explosive welding.Based on C276-304 L explosive-welded composite,this work investigated the diffusion behavior of main elements(Ni,Fe)near the bonding interface during the explosive welding process through molecular dynamics(MD)simulations and experiment.(1)According to the characters of temperature and pressure of explosive welding process,the simulation of explosive welding process was classified into three stages,namely loading stage,unloading stage,and cooling stage.According to the characteristics of the three stages during the welding process,different ensembles were applied to different stages.Different boundary conditions were applied in different directions.The stability of the atomic structure during the relaxation process was investigated as the method to evaluate the applicability of the potential function and the reliability of the model.(2)Four sets of welding parameters for MD simulation were set in this article.According to the results of MD simulation,the variation characteristics of temperature and pressure in different stages were discussed.By comparing the mean square displacement(MSD)of the main elements and system configurations of different stages,the atomic diffusion near the interface during the explosive-welded process was investigated.(3)The atomic structures of three stages were investigated by pair distribution function(PDF),and the effect of melting on atomic diffusion behavior during the explosive welding process was explored,the results show that: if solid-solid diffusion occurred at the interface,only a small number of atoms can diffuse into the opposite side of the interface,and only when liquid-solid diffusion or even liquid-liquid diffusion occured at the interface,the atoms at the interface can diffuse obviously.The microstructure of the bonding zone of C276-304 L explosive welded composite plate was investigated on experiment,and the melting and diffusion phenomena at the interface of composite during welding were discussed.The effect of welding parameters on the thickness of the diffusion layer was investigated.