Investigating the impact and mechanisms of electromagnetic treatment on stress corrosion performance in 7075 aluminum alloy

Electromagnetic treatment (EMT) plays a critical role in the manipulation of microstructures and properties in aluminum alloys. This study aims to investigate the impact of EMT on stress corrosion cracking (SCC) resistance in 7075 aluminum alloy and to reveal the underlying mechanisms from both thermodynamic and kinetic perspectives. The results demonstrate that EMT has a significant positive effect on the stress corrosion resistance of the aluminum alloy. It effectively reduces the elongation loss from 11.2 to 2.6% and the SCC susceptibility index from 3.9 to 1.4%. This improvement can be attributed to two primary mechanisms: (1) the energy supplied by the electromagnetic field lowers the thermodynamic barriers for the dissolution of precipitates, even at temperatures below the critical threshold. This facilitates the dissolution and coarsening of precipitates, ultimately reducing the alloy's susceptibility to stress corrosion in various environments. (2) The activation energy provided by the electron wind force facilitates the movement and annihilation of dislocations, leading to a reduction in residual stresses and further enhancing the aluminum alloy's resistance to stress corrosion.