Abstract
Microstructural improvement of Al-Cu-Li alloys with high Li content plays a critical role for the acquisition of excellent mechanical properties and ultra-low density. In this regard, the Al-Cu-Li alloy castings with high Li content from 1.5wt.% to 4.5wt.% were prepared by near-rapid solidification, followed by two-stage homogenization treatment (490 °C/16 h and 530 °C/16 h). The microstructural evolution and solidification behavior of the as-cast and homogenized alloys with different Li contents were systematically studied by combining experiments with calculations by Pandat software. The results indicate that with the increase of Li content, the grain sizes decrease, the solution ability of Cu in the matrix α-Al phase increases, while the content of secondary dendrites increases and the precipitated phases change from low melting point phases to high melting point phases under the near-rapid solidification. Additionally, by the coupling of near-rapid solidification and two-stage homogenization, the metastable precipitated phases (Al7Cu4Li and AlCu3) can be dissolved effectively in the alloys with Li content of 1.5wt.%–2.5wt.%; moreover, the stable precipitated phases (Al6CuLi3 and Al2CuLi) uniformly distribute at the grain boundaries in the alloys with Li content of 3.5wt.%–4.5wt.%. As a result, the refined and homogenized microstructure can be obtained.
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Dorin T, Deschamps A, Geuser F, et al. Quantification and modelling of the microstructure/strength relationship by tailoring the morphological parameters of the T1 phase in an Al-Cu-Li alloy. Acta Materialia, 2014, 75: 134–146.
Shi C L, Xi X K. NMR investigation of atomic bonding properties in Al-Li alloys. Intermetallics, 2014, 51: 64–67.
Rioja R J, Liu J. The evolution of Al-Li base products for aerospace and space applications. Metallurgical and Materials Transactions A, 2012, 43 (9): 3325–3337.
Evans J W. The evolution of technology for light metals over the last 50 years: Al, Mg, and Li. JOM, 2007, 59 (2): 30–38.
Williams J C, Starke E A. Progress in structural materials for aerospace systems. Acta Mater, 2003, 51: 5775–5799.
Lavernia E J, Srivatsan T S, Mohamed F A. Strength, deformation, fracture behaviour and ductility of aluminium-lithium alloys. Journal of Materials Science, 1990, 25 (2): 1137–1158.
Wu L, Zhou C, Li X F, et al. Microstructural evolution and mechanical properties of cast high-Li-content TiB2/Al-Li-Cu composite during heat treatment. Journal of Alloys and Compounds, 2018, 739: 270–279.
Wang S C, Starink M J. Precipitates and intermetallic phases in precipitation hardening Al-Cu-Mg-(Li) based alloys. International Materials Reviews, 2005, 50: 193–215.
Xu X, Song T, Fan Z, et al. Microstructure and dislocation strengthening of Sc microalloyed 2099 Al-Li alloy. Rare Metal Materials and Engineering, 2012, 41: 621–624.
Wu L, Li X F, Han G Y, et al. Precipitation behavior of the high-Li-content in-situ TiB2/Al-Li-Cu composite. Materials Characterization, 2017, 132: 215–222.
Balducci E, Ceschini L, Messieri S. High temperature tensile tests of the lightweight 2099 and 2055 Al-Cu-Li alloy: A comparison. JOM, 2018, 70 (11): 2716–2725.
Zhang F, Shen J, Yan X D, et al. Homogenization heat treatment of 2099 Al-Li alloy. Rare Metals, 2014, 33 (1): 28–36.
Shanmugasundaram T, Murty B S, Sarma V S. Development of ultrafine grained high strength Al-Cu alloy by cryorolling. Scripta Materialia, 2006, 54 (12): 2013–2017.
Kim W J, Chung C S, Ma D S, et al. Optimization of strength and ductility of 2024 Al by equal channel angular pressing (ECAP) and post-ECAP aging. Scripta Materialia, 2003, 49 (4): 333–338.
Deng Y J, Huang G J, Cao L F, et al. Improvement of strength and ductility of Al-Cu-Li alloy through cryogenic rolling followed by aging. Transactions of Nonferrous Metals Society of China, 2017, 27 (9): 1920–1927.
Yang S L, Shen L, Yan X D, et al. Homogenization treatment parameter optimization and microstructural evolution of Al-Cu-Li alloy. Rare Metal Materials & Engineering, 2017, 46(1): 28–34.
Yang S L, Shen J, Zhang Y A, et al. Processing maps and microstructural evolution of Al-Cu-Li alloy during hot deformation. Rare Metals, 2017, 6: 1–8.
Lavernia E J, Ayers J D, Srivatsan T S. Rapid solidification processing with specific application to aluminium alloy. International Materials Reviews, 1992, 37 (1): 1–44.
Wang Y, Lorimer G W, Sale F R. Microstructural development during consolidation of rapidly solidified Al-Fe-V-Si powder by VHP, extrusion and rolling. Scripta Metallurgica et Materialia, 1994, 31 (10): 1337–1342.
Tang Y P, Tan D Q, Li W X, et al. Preparation of Al-Fe-V-Si alloy by spray co-deposition with added its over-sprayed powders. Journal of Alloys and Compounds, 2007, 439 (1–2): 103–108.
Liu Y L, Luo L, Shun M Z, et al. Microstructure and mechanical properties of Al-5.5Fe-1.1V-0.6Si alloy solidified under near-rapid cooling and with Ce addition. Rare Metals, 2016, 37 (12): 1070–1075.
Liu Y L, Liu M, Luo L, et al. The influence of cooling rate and alloying elements on the microstructure refinement of Al-5Fe alloy. Orlando: TMS Annual Meeting: Light Metals, 2015: 271–275.
Donnadieu P, Shao Y, Geuser F, et al. Atomic structure of T1 precipitates in Al-Li-Cu alloys revisited with HAADF-STEM imaging and small-angle X-ray scattering. Acta Materialia, 2011, 59 (2): 462–472.
Jia P F, Cao Y H, Geng Y D, et al. Effects of DC current on the phase transformation in 7050 alloy during homogenization. Materials Characterization, 2014, 96: 21–27.
Radetic T, Popovic M, Romhanji E. Microstructure evolution of a modified AA5083 aluminum alloy during a multistage homogenization treatment. Materials Characterization, 2012, 65: 16–27.
Qing L, Zhu R, Li J, et al. Microstructural evolution of Mg, Ag and Zn micro-alloyed Al-Cu-Li alloy during homogenization. Transactions of Nonferrous Metals Society of China, 2016, 26(3): 607–619.
Lloyd D J. Particle reinforced aluminium and magnesium matrix composites. International Materials Reviews, 1994, 39(1): 1–23.
Li J F, Liu P L, Chen Y L, et al. Microstructure and mechanical properties of Mg, Ag and Zn multi-microalloyed Al-(3.2-3.8)Cu-(1.0-1.4) Li alloys. Transactions of Nonferrous Metals Society of China, 2015, 25 (7): 2103–2112.
Mørtsell E A, Marioara C D, Andersen S J, et al. The effects and behaviour of Li and Cu alloying agents in lean AløMgøSi alloys. Journal of Alloys and Compounds, 2017, 699: 235–242.
Zhang L, Zheng Z Q, Li J F, et al. Microstructural evolution and mechanical properties of a new AløCuøLiøX alloy at different solution temperatures. Rare Metals, 2016 (1):1–8.
Kabisch O, Gille W, Krol J. The effect of copper addition on the structure and strength of an Al-Li alloy. Materials & Design, 1997, 18 (4–6): 385–388.
Ivanov R, Deschamps A, Geuser F. High throughput evaluation of the effect of Mg concentration on natural ageing of AløCuøLiø(Mg) alloys. Scripta Materialia, 2018, 150: 156–159.
Araullo-Peters V, Gault B, Geuser F, et al. Microstructural evolution during ageing of Al-Cu-Li-X alloys. Acta Materialia, 2014, 66: 199–208.
Liu G, Gong M, Xie D, et al. Structures and mechanical properties of Al-Al2Cu Interfaces. JOM, 2019, 71(4): 1200–1208.
Acknowledgements
This research was financially supported by the National Key Research and Development Program of China (Grant No. 2017YFA0403804), and the National Natural Science Foundation of China (Grant No. 51425402).
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Yan-qing Su
Male, Ph.D, Professor. His research interests mainly focus on the development and preparation of new materials, solidification theory, and special casting technology. To date, he has published 4 books and more than 310 papers, and holds 27 invention patents of China.
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Luo, L., Luo, Ls., Li, Zp. et al. Microstructural evolution of Al-Cu-Li alloys with different Li contents by coupling of near-rapid solidification and two-stage homogenization treatment. China Foundry 17, 190–197 (2020). https://doi.org/10.1007/s41230-020-0001-y
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DOI: https://doi.org/10.1007/s41230-020-0001-y
Key words
- Al-Cu-Li alloys
- ultra-low density
- near-rapid solidification
- two-stage homogenization treatment
- microstructural evolution