The role of Sn element on the deformation mechanism and precipitation behavior of the Al–Cu–Mg alloy

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2020-08, Vol.792, p.139838, Article 139838
• Main Authors: Dai, Shuai, Bian, Zeyu, Wu, Wenbo, Tao, Jiongming, Cai, Ling, Wang, Mingliang, Xia, Cunjuan, Wang, Haowei
• Format: Article
• Language: English
• Subjects: Aging (artificial); Aging (natural); Aluminum base alloys; Al–Cu–Mg alloy; Clusters; Copper; Deformation effects; Deformation mechanism; Deformation mechanisms; Dynamic recrystallization; Dynamic stability; Grain growth; Grain sub boundaries; Magnesium compounds; Mechanical tests; Microstructure; Microstructure characterization; Nucleation; Precipitation behavior; Room temperature; Sn element; Solution heat treatment; Stannides; Thermal stability; Vacancies
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2020.139838

The deformation mechanism and precipitation behavior of Al-5.8Cu-0.35 Mg-(0.3Sn) (wt.%) alloys were intensively investigated by microstructure characterizations and mechanical tests in this work. The experimental results showed that the added Sn elements can induce profound impacts on the alloys in three manners: (1) the formation of Mg2Sn particles with excellent thermal stability can create particle-stimulated nucleation effect to facilitate dynamic recrystallization during hot deformation. Furthermore, the fine Mg2Sn particles distributed at subgrain boundaries obviously inhibited the recrystallized grain growth during the solution treatment; (2) the suppression of natural aging was because there was insufficient releasing of vacancies from Sn-vacancy clusters at room temperature; (3) the accelerated artificial aging with lowered hardening effect was owing to both Sn-vacancy clusters inhibited the annihilation of quenching vacancies and reduced concentration of solute Mg consumed by the stable Mg2Sn particles. Finally, the underlying mechanisms were elucidated in combination microstructure features with mechanical responses in the alloys. •Stronger dynamic recrystallization was induced in Al–Cu–Mg–Sn alloy.•Natural aging was effectively inhibited by stable Sn-vacancy clusters.•The precipitation phases of peak-aged alloy were altered by added Sn.•Dislocation path was used to explain the coarsening of θ′′ at over-stage state.