Twin crystal structured Al-10 wt.％ Mg alloy over broad velocity conditions achieved by high thermal gradient directional solidification

Luyan Yang ¹Shuangming Li ²Kai Fan ²Yang Li ²Yanhui Chen ³Wei Li ³Deli Kong ⁴Pengfei Cao ⁵Haibo Long ³Ang Li³

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作者信息

1. Institute of Microstructure and Properties of Advanced Materials, Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing,100124, China;State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an, 710072, China;Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich, 52428,Jülich, Germany
2. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an, 710072, China
3. Institute of Microstructure and Properties of Advanced Materials, Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing,100124, China
4. Institute of Microstructure and Properties of Advanced Materials, Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing,100124, China;Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich, 52428,Jülich, Germany
5. Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich, 52428,Jülich, Germany
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Abstract

Twin crystal structured Al-10 wt.％ Mg alloys that were grown over a broad solidification velocity range were prepared and studied for the first time.The high thermal gradient (G) and growth velocity (V) of directional solidification resulted in the dominant solidification of twins: the twinned dendrite trunks at constant high Vs curved in the G direction with large angles in 7 mm diameter crucibles and invaded regular columnar grains because of a distinct kinetics growth advantage.Transitive deceleration experiments were designed to produce twin crystals that evolved with lower values of V (100,10,and 0.5 μm/s) and had a structural coarsening trend.Twin cell growth in the absence of arms occurred at a growth velocity of 10 μm/s.A coherency loss was observed at a growth velocity of 0.5 μm/s with straight coherent twin boundaries turning into curved incoherent boundaries.Linear theoretical analyses were performed to understand the structural evolution of the twins.These results demonstrate the possibility of producing dense and controlled twin crystals in the Al-Mg system under most industrial production conditions;thus,this approach can be a new structural choice for designing Al-Mg-based alloys that have widespread commercial applications.

Key words

Directional solidification/Aluminum alloy/Microstructural evolution/Feathery crystals/Twinned dendrites

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基金项目

Basic Science Center Program for Multiphase Media Evolution in Hypergravity of the National Natural Science Foundation of China(51988101)

国家自然科学基金(51974257)

国家自然科学基金(91860202)

China Postdoctoral Science Foundation(2018M640031)

fund of the State Key Laboratory of Solidification Processing (Northwestern Polytechnical University)(SKLSP202008)

fund of the State Key Laboratory of Solidification Processing (Northwestern Polytechnical University)(2019-TS-01)

高等学校学科创新引智计划(111计划)(DB18015)

Beijing Outstanding Young Scientists(ProjectsBJJWZYJH01201910005018)

出版年

2021

材料科学技术(英文版)

中国金属学会中国材料研究学会中国科学院金属研究所

材料科学技术(英文版)

CSTPCDCSCDSCI

影响因子：0.657

ISSN：1005-0302

参考文献量38

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