Ca-modified Al–Mg–Sc alloy with high strength at elevated temperatures due to a hierarchical microstructure

Ca-modified Al–Mg–Sc alloy with high strength at elevated temperatures due to a hierarchical microstructure

Du, Haiquan (Nanjing University of Aeronautics and Astronautics; Ministry of Industry and Information Technology)
Zhang, Shasha (Nanjing University of Aeronautics and Astronautics; Ministry of Industry and Information Technology)
Zhang, Bingyi (Nanjing University of Aeronautics and Astronautics; Ministry of Industry and Information Technology)
Tao, Xuewei (Nanjing Institute of Technology)
Yao, Zhengjun (Nanjing University of Aeronautics and Astronautics; Ministry of Industry and Information Technology)
Belov, Nikolay (National University of Science and Technology MISiS)
van der Zwaag, S. (TU Delft Novel Aerospace Materials)
Liu, Zili (Nanjing University of Aeronautics and Astronautics)

2021

Al-Mg alloys are normally prone to lose part of their yield and tensile strength at high temperatures due to insufficient thermal stability of the microstructure. Here, we present a Ca-modified Al–Mg–Sc alloy demonstrating high strength at elevated temperatures. The microstructure contains Al₄Ca phases distributed as a network along the grain boundary and Al₃(Sc,Zr) nano-particles dispersed within the grains. The microstructure evolution and age-hardening analysis indicate that the combination of an Al₄Ca network and Sc-rich nano-particles leads to excellent thermal stability even upon aging at 300 °C. The tensile strength of the alloy for temperatures up to 250 °C is significantly improved by an aging treatment and is comparable with the commercial heat-resistant aluminum alloys, i.e., A356 and A319. At a high temperature of 300 °C, the tensile strength is superior to the above-mentioned commercial alloys, even more so when expressed as the specific strength due to the low density of Ca-modified Al–Mg–Sc alloy. The excellent high-temperature strength results from a synergistic effect of solid solution strengthening, grain boundary strengthening and nanoparticle order strengthening.

http://resolver.tudelft.nl/uuid:6379b6bf-c351-4921-aafd-29b027dcc7b7

https://doi.org/10.1007/s10853-021-06310-5

2022-01-10

0022-2461

Journal of Materials Science, 56 (28), 16145-16157

Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

Institutional Repository

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© 2021 Haiquan Du, Shasha Zhang, Bingyi Zhang, Xuewei Tao, Zhengjun Yao, Nikolay Belov, S. van der Zwaag, Zili Liu