Influence of High Magnetic Field-Thermal Coupling Processing on Diffusion Bonding Properties and Element Diffusion of 1420 Al-Li Alloy

Abstract

The high uniform magnetic field combined with pre-deformation and vacuum heat treatment processing is designed for improving the diffusion bonding properties of the 1420 Al-Li alloy. Serial magneto-thermal coupling treatment experiments of 1420 Al-Li alloy and the pure aluminium diffusion couple, together with the gallium interlayer, is carried out in a superconducting high magnetic field device. Various parameter combinations are used to produce different samples on which interface organization and connection performance are studied. Electron microscopic analysis reveals various interface topographies and fracture morphologies after shear strength tests. Influence of diffusion bonding temperature on element diffusion under a high uniform magnetic field is investigated. The diffusion activation energy of Mg element in pure aluminum under a 12 T magnetic field is calculated in this paper. It is found that the bonding quality and bonding performance of the interface are improved greatly after heat treatment with a strong magnetic field, and the bonding temperature is an important factor affecting the interface bonding and bonding strength. The diffusion coefficient of the Mg element in the 1420 Al-Li alloy to L2 pure aluminum increases with the increase of diffusion bonding temperature. Reducing the activation energy of elemental diffusion is beneficial to atomic diffusion.