Diffusion mechanism in liquid Al–Cu melt under high magnetic field

High static magnetic field (HMF) is now a widely used technique to tailor materials. However, as one of the most fundamental properties in liquid alloy melts, atomic diffusion under HMF still lacks understanding. By using a novel gravity-assisted automatic docking device, the interdiffusion coefficient (IDC) in liquid Al–Cu alloy at various temperatures has been studied under HMF. It is found that HMF reduces the IDC. When HMF is larger than 5 T, the value of IDC remains constant at a certain temperature, which indicates HMF changes the diffusion mechanism from convective dominated mass transfer to a diffusive limited state in the liquid melt. For various temperatures, we find that a decrease of the frequency factor of atoms is the main reason for IDC decreasing under a certain HMF. The diffusion mechanism in liquid melt is similar to the vacancy mechanism in solids. This work provides a deep insight for atomic diffusion in a liquid melt by considering the interaction between temperature and HMF.