Effects of a short-duration preprecipitation process prior to predeformation aging on the mechanical properties and corrosion resistance of Al-Cu-Mg-Ag alloy

Abstract

Purpose The effects of the thermo-mechanical treatment on the properties and microstructure of the Al–Cu–Mg–Ag alloy were investigated. Design/methodology/approach A short-duration preprecipitation process is designed prior to predeformation aging. The novel predeformation aging (solution treatment + holding at 185 °C for 15 min+ rolling deformation + aging at 185 °C, also named T8) was performed on a heat-resistant Al–Cu–Mg–Ag alloy. Findings The purpose of this study indicate that a short-duration heat treatment before predeformation is beneficial to the precipitation of O during the aging process. The precursors of O during this process might pin the dislocation and cause the grains to orient along some specific direction, which might be advantageous to the precipitation of O while disadvantageous to that of θ′. This novel thermal-mechanical process could result in an increase in the quantity and decrease in the size of the precipitation of O, which leads to a remarkable strength effect. The potential increases while the current density decreases with an increase in the deformation amount, which implies a smaller intergranular corrosion rate. The fine deformed structure leads to an opposite behavior in the exfoliation corrosion test compared with that for intergranular corrosion. Originality/value The intergranular corrosion resistance of the Al–Cu–Mg–Ag alloy is enhanced, whereas the exfoliation corrosion resistance is reduced by novel predeformation aging.

Corrosion property of Al alloys subjected to surface severe plastic deformation: a review

“…Due to the complex microstructures such as precipitates and precipitates-free zone (PFZ) distributed along/near grain boundaries, IGC can easily occur in Al alloys (Wang et al , 2022). For 2000 and 7000 series ultra-high strength Al alloys, IGC is more common and more detrimental than uniform corrosion and often leads to catastrophic cracking.…”