Partial dissolution of strengthening particles induced by equal channel angular pressing in an Al–Li–Cu alloy

An Al–Li–Cu (AA2091) alloy was subjected to equal channel angular pressing (ECAP) at 210 °C following route BC to a maximum strain of ε = 8.64. A considerable particle age hardening anticipation with respect to an isochronal aging treatment was documented. At ε = 6.48, the alloy reached a peak hardness level, while at ε = 8.64, the alloy overaged and partial dissolution of the two most abundant hardening particles, T1 plates and S' laths, was induced by ECAP/BC.

► Both ECAP/BC and dwelling at 210 °C determined the aging response of the studied Al–Li–Cu alloy. ► Hardening phase precipitation was quantitative evaluated for different strain levels by TEM inspections. ► Peak hardening anticipation occurring at ε = 8.64 (corresponding to 8 ECAP/BC passes). ► ECAP induced partial T1 and S′ particle dissolution phenomena at the overaged condition (ε = 8.64).