Designing structures with combined gradient of potential and precipitation in multi-layered aluminum sheet for simultaneous improvement of mechanical properties and corrosion resistance

Abstract

The effects of an interlayer on the corrosion resistance and mechanical properties of multi-layered aluminum sheets were studied. The interlayer prevents Si diffusion to the core layer and optimizes the potential gradient from the Zn-containing interlayer to the core layer. The presence of the interlayer changes the corrosion mode from pitting and intergranular corrosion (IGC) to exfoliation corrosion. Additionally, the natural aging process forms Guinier-Preston (GP) zones in the core layer, which improves the material's yield strength. First principle calculations show that there is minimal corrosion between the GP zones and Al matrix. Thus, the mechanical properties and corrosion resistance of multi-layered aluminum sheets are improved simultaneously.