Nucleation and evolution of β phase and corresponding intergranular corrosion transition at 100–230 °C in 5083 alloy containing Er and Zr. (15th July 2019)

• Record Type: Journal Article
• Authors: Ding, Yusheng; Gao, Kunyuan; Huang, Hui; Wen, Shengping; Wu, Xiaolan; Nie, Zuoren; Guo, Shanshan; Shao, Rui; Huang, Cheng; Zhou, Dejing
• Is Part Of: Materials & design. Volume 174(2019)
• Publication Date: 2019-07-15
• Subjects: Aluminum alloy -- Microstructure -- Corrosion -- Classical nucleation theory -- Diffusion; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2019.107778
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: The intergranular corrosion and β phase evolution of 5083 aluminum alloy containing Er and Zr during annealing at 100–230 °C were studied using mass loss tests and transmission electron microscopy. The mass loss curves showed that when annealing temperature changed from 200 to 220 °C, the alloy was subjected to a transition from sensitized state to stabilized state, corresponding to the change of nucleation position of β precipitates from grain boundaries to triple junctions. Particularly, when the annealing temperature was at 210 °C, this transition could also happen when the annealing time was increased from 0.5-10 h to 15-24 h, associated with the change in the shape of β precipitates. The classical nucleation analysis with the consideration of Mg segregation showed the nucleation rates at grain boundary and triple junction were 10 13 and 10 11 m −3 s −1 at sensitization temperature 150 °C, but 10 9 and 10 10 m −3 s −1 at stabilization temperature 220 °C, suggesting the change of nucleation site with increasing temperature. The analysis of diffusion flux of Mg around β precipitate suggested that the shape change of β precipitates from elongate to spheroidal at 210 °C was attributed to the dominant interface diffusion over the grain boundary diffusion with the increase of time. Graphical abstract: Unlabelled Image Highlights: The intergranular corrosion and microstructure in 5083 alloy with Er and Zr upon annealing were systematically studied. The transition of sensitized to stabilized state was attributed to different nucleation locations of β phase at 200-220°C. The sensitization and reversal process at 210°C was attributed to elongation and spheroidization of grain boundary β phase. The nucleation rate and the morphology evolution of β phase along grain boundary were intensively discussed.