Fe/W扩散焊界面原子扩散行为分子动力学模拟OACSTPCD

To investigate the effect of process parameters on the atomic diffusion behavior at the Fe/W interface,a low index crystal plane Fe(100)/W(100)interface structure model was established.Molecular dynamics(MD)method was used to simulate atomic diffusion at the Fe/W interface at 1 123～1 323 K,and the specific diffusion situation was observed and the diffusion coefficient was calculated.Results indicate that there is a significant asymmetric diffusion phenomenon at the Fe/W interface,mainly due to the diffusion of W atoms into Fe atoms,and the longer the simulation time,the more obvious this phenomenon becomes.The radial distribution function(RDF)indicates that the ordering degree on the Fe side is higher than that on the W side.According to the mean square displacement(MSD)curve fitting,the diffusion coefficient and diffusion activation energy were obtained.At temperatures of 1 123～1 323 K,the diffusion activation energies of Fe and W at the Fe/W interface were 1.326 and 0.841 56 eV,respectively.The absolute value of the diffusion potential energy of W atom in Fe crystal is lower,making it easier to break through the energy barrier.The increasing of diffusion temperature and pressure can effectively increase the thickness of the interface diffusion layer.Increasing roughness of the interface to some extent is beneficial for increasing the thickness of the diffusion layer,but it also affects the interface closure.The basic data of diffu-sion coefficient can provide a theoretical basis for the microstructure control of diffusion bonding interface between low acti-vation steel and tungsten facing the first wall material in actual industrial production.