Effect of ECAP and aging on microstructure of an Al-Cu-Mg-Si alloy

• Published in: Materials characterization Vol. 218; p. 114500
• Main Authors: Gazizov, M.R., Mironov, S.Yu, Holmestad, R., Gazizova, M.Yu, Kaibyshev, R.O.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01-12-2024
• Subjects: Al-Cu-Mg-Si alloy; Electron microscopy; Mechanical properties; Microstructure; Precipitation; Severe plastic deformation; Thermomechanical processing; Severe plastic deformation; Precipitation; Thermomechanical processing; Mechanical properties; Microstructure; Electron microscopy; Al-Cu-Mg-Si alloy
• ISSN: 1044-5803
• DOI: 10.1016/j.matchar.2024.114500

The effect of equal-channel-angular pressing (ECAP) on the microstructure and precipitation of an Al-4.7Cu-0.74 Mg-0.51Si-0.48Mn-0.10Cr-0.09Ti-0.02Fe (all wt%) has been studied using aberration-corrected scanning transmission electron microscopy. The ECAP followed by a short-term aging provides a superior combination of strength and ductility in the present alloy. The ECAPed alloy shows a substantially different precipitation behavior in the deformation bands (DBs) compared to extended regions (ERs) during aging. The relatively coarse particles of the equilibrium θ (Al2Cu) and β (Mg2Si) phases were found to form along deformation-induced grain/subgrain boundaries within the DBs after short-term aging. In the present alloy after ECAP and aging, the phases continuously decorating dislocation lines or forming the discrete particles in the ERs are similar to those in the bulk matrix after conventional aging. The macroscopic strengths have been estimated for the ERs and DBs in the samples after ECAP and aging. The former, i.e., ERs, with predominant strengthening contributions originating from solid solution, precipitation and dislocations, is likely have a higher YS than the latter with the relatively coarse equilibrium particles and mainly strengthened by only grain boundaries and dislocations.
•ECAP and short-term aging provide a superior strength-ductility combination.•Precipitation is classified in deformation bands (DBs) and extended regions (ERs).•Coarse equilibrium particles appear along thin DBs after ECAP and aging.•Precipitation in ERs with dislocations is similar to that after conventional aging.•Highest strength is provided by grain boundary and dislocation strengthenings.