| LIGHTWEIGHT ALLOYS |
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| Microstructure Heredity and High Yield Strength Design of Fine Grained Al-Si-Mg Alloys |
| LI Daoxiu1, HAN Mengxia1, ZHANG Jiang2, PENG Yinjiang2, SUN Qianqian1,3, LIU Guiliang1,3, LIU Xiangfa1,*
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1 Key Laboratory for Liquid-Solid Structural Evolution & Processing of Materials of Ministry of Education, Shandong University, Jinan 250061, China
2 Ningbo Branch of Chinese Academy of Ordnance Science, Ningbo 315103, China
3 Shandong Al & Mg Melt Tech. Co., Ltd., Jinan 250061, China |
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Abstract The grain size of conventional Al-Si-Mg alloy ingot (such as A356 cast ingot) is abnormally coarse, which leads to the casting defects of microstructure shrinkage and porosity, uneven structure composition and poor performance after remelting. Therefore, it is very important to control its grain size effectively. In this work, a fine grained A356 alloy was remelted and its microstructure heredity was studied. The Al-Si-Mg alloy with high strength was designed by using the fine grain A356 aluminum alloy. To reveal the correlative heredity mechanism, the nucleation particle of the fine grained A356 aluminum alloy was characterized by electron microprobe (EPMA), and the solidification process was analyzed by differential scanning calorimetry (DSC). The results showed that the average grain size of the fine grained A356 aluminum alloy was 74.9 μm after remelting. It is found that the α-Al grains of the fine grained A356 aluminum alloy contains ternary compound TiCB particles (TCB). The particles are stable in the remelted A356 aluminum alloy, which are able to reduce the supercooling degree of the alloy. Therefore, even if remelted for a long time, it is qualified for α-Al nucleating and retain the high-efficiency refining effect. In addition, the tensile strength of the fine grain A356 aluminum alloy after remelting is 312.5 MPa, and the elongation reaches 12.5%. On this basis, a small amount of Mg was added to improve the strength. The designed Al-Si-Mg alloy has excellent mechanical property. The tensile strength and yield strength of Al-7Si-0.8Mg alloy are 386.4 MPa and 352.9 MPa, respectively, while the elongation remains at 3.9%.
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Published: 31 May 2021
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| Fund:National Natural Science Foundation of China (52071189) and Major Special Projects of Ningbo 2025 (2019B10099). |
About author:: Daoxiu Li, a docroral student at Shandong University (SDU), received her master's degree in materials engineering from Northwestern Polytechnical University (NWPU) from September 2016 to April 2019. She has been studying for her doctorial degree at Shandong University (SDU) since 2019. Her research work mainly focuses on the refinement and strengthening design of aluminum alloy, especially Al-Si alloy.
Xiangfa Liu, a professor at Shandong University and a supervisor for doctoral students. He is a recipient of the National Science Foundation for Distinguished Young Scholars, a Taishan Scholar and a middle-aged expert with outstanding contributions in Shandong Province. His main research interests include the theory of structure evolution and regulation of liquid metal clusters, the development and microstructure regulation of nanocrystalline seed alloys, and the innovation of heat-resi-stant and high-strength aluminum alloys and their composites. He has undertaken more than 20 national and provincial level projects, including the Na-tional 973 Project, the National Fund for Distinguished Young Scholars, the National Natural Science Foundation of China and other key and general projects. He has authorized 28 national invention patents and industrialized 18 of them, and has published more than 200 papers indexed by SCI, which have been cited for more than 2 500 times. |
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1 Niu L Q, Cao M, Liang Z L, et al. Materials Science and Engineering: A,2020,789,139612.
2 Wang M J, Hu K Q, Liu G L, et al. Journal of Alloys and Compounds,2020,814,152217.
3 Xia X C, Zhao Q F, Peng Y Y, et al. Journal of Alloys and Compounds,2020,818,153370.
4 López V H, Scoles A, Kennedy A R. Materials Science and Engineering: A,2003,356(1-2),316.
5 Ding H M, Liu X F. Transactions of Nonferrous Metals Society of China,2011,21(7),1465.
6 Li Y, Hu B, Liu B, et al. Acta Materialia,2020,187,51.
7 Qiu D, Taylor J A, Zhang M X, et al. Acta Materialia,2007,55(4),1447.
8 Xu Y, Casari D, Du Q, et al. Acta Materialia,2017,140,224.
9 Fan Z, Wang Y, Zhang Y, et al. Acta Materialia,2015,84,292.
10 Birol Y. Journal of Alloys and Compounds,2012,513,150.
11 Bolzoni L, Hari Babu N. Journal of Materials Research and Technology,2019,8(6),5631.
12 Chen Z N, Kang H J, Fan G H, et al. Acta Materialia,2016,120,168.
13 Li P, Liu S, Zhang L, et al. Materials & Design,2013,47,522.
14 Xu J, Li Y, Ma K, et al. Scripta Materialia,2020,187,142.
15 Li Q, Qiu F, Dong B X, et al. Materials Science and Engineering: A,2020,798,140247.
16 Kang J, Su R, Wu D Y, et al. Journal of Alloys and Compounds,2019,796,267.
17 Gao J L. Light Metals,1985(11),55(in Chinese).
高晶丽.轻金属,1985(11),55.
18 Zhang J S. Principle of liquid metal forming, Chemical Industry Press, China,2011(in Chinese).
张金山.金属液态成型原理,化学工业出版社,2011.
19 StJohn D H, Qian M, Easton M A, et al. Acta Materialia,2011,59(12),4907.
20 StJohn D H, Easton M A, Qian M, et al. Metallurgical and Materials Transactions A,2012,44(7),2935.
21 Tsai Y C, Chou C Y, Lee S L, et al. Journal of Alloys and Compounds,2009,487(1-2),157. |
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2021, Vol. 35 
