Manipulating Precipitation Through Thermomechanical Treatment to Control Corrosion Behavior of an Al-Cu-Mg Alloy

Controlling the precipitation through thermomechanical treatment is an important method to improve the corrosion resistance of Al-Cu-Mg alloys. In this study, the corrosion behaviors of Al-Cu-Mg alloys in the solution-treated state and retrogression-treated state under cold rolling deformation and then natural aging were investigated. In the solution-treated series alloys, the cold-rolled deformation improved the resistance to intergranular corrosion by suppressing the precipitation of the S-phase on the grain boundaries. The increased pitting potential and corrosion potential were related to the increased concentration of solute atoms within the grain interiors and the eliminated S-phase on grain boundaries. In the retrogression-treated series alloys, the 30% cold rolling deformation stimulated the growth of the S-phase and transformed the S-phase distribution from discontinuous to continuous on the grain boundaries, thereby changing the pitting corrosion to the network corrosion morphology. The precipitation of the S-phase with large dimension within the grain interiors contributed to the decreased pitting potential and corrosion potential.

Automated summary

Controlling precipitation through thermomechanical treatment is an important method to enhance the corrosion resistance of Al-Cu-Mg alloys. Cold rolling deformation can improve the resistance to intergranular corrosion in the solution-treated state, while cold rolling deformation in the retrogression-treated state changes the corrosion morphology from pitting to network corrosion.