Microstructure refinement and mechanical properties of eutectic Mg2Si reinforced Mg matrix composites containing Sr element

In this study, in–situ eutectic Mg2Si reinforced AZ61 composites unmodified and modified with Sr addition are fabricated. The effects of Sr addition on the morphology and size of Mg2Si phase, α–Mg matrix grains, its refining mechanism and mechanical properties of Mg2Si/AZ61 composites are investigat...

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Main Authors: Yixue Dong, Peng Xiao, Yimin Gao, Qiqiang Zhao, Haocheng Yang
Format: Article
Language:English
Published: Elsevier 2022-03-01
Series:Journal of Materials Research and Technology
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S2238785422002058
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author Yixue Dong
Peng Xiao
Yimin Gao
Qiqiang Zhao
Haocheng Yang
author_facet Yixue Dong
Peng Xiao
Yimin Gao
Qiqiang Zhao
Haocheng Yang
author_sort Yixue Dong
collection DOAJ
description In this study, in–situ eutectic Mg2Si reinforced AZ61 composites unmodified and modified with Sr addition are fabricated. The effects of Sr addition on the morphology and size of Mg2Si phase, α–Mg matrix grains, its refining mechanism and mechanical properties of Mg2Si/AZ61 composites are investigated. The results show that the morphology of eutectic Mg2Si phases in Mg2Si/AZ61 composites is significantly modified from coarse Chinese character to polygonal shape with Sr addition, and Sr atoms are preferentially absorbed on the {100} surfaces of Mg2Si phase, which suppresses the preferred growth along <100> direction. Besides, some Sr atoms dissolved into the Mg2Si lattice, change the growth mode and improve its morphology. Moreover, Al4Sr formed during solidification act as the heterogeneous nucleation core of Mg2Si, to refine the size of Mg2Si from 11.37 to 2.11 μm. Meanwhile, the average size of α–Mg matrix is also refined to 50.4 μm, decreased by 49.7%, indicating that both eutectic Mg2Si phase and α–Mg grains were significantly refined by Sr addition. Compared with unmodified Mg2Si/AZ61 composite, the strength and ductility of Sr modified Mg2Si/AZ61 composites are improved simultaneously, especially the ductility increased by 63%.
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spelling doaj.art-105b2096b66048fc95178019cb4577f62022-12-21T23:52:08ZengElsevierJournal of Materials Research and Technology2238-78542022-03-011726142623Microstructure refinement and mechanical properties of eutectic Mg2Si reinforced Mg matrix composites containing Sr elementYixue Dong0Peng Xiao1Yimin Gao2Qiqiang Zhao3Haocheng Yang4State Key Laboratory for Mechanical Behavior of Materials, School of Materials Science and Engineering, Xi'an Jiaotong University, No. 28, Xianning West Road, Xi'an, Shaanxi Province, 710049, PR ChinaCorresponding author.; State Key Laboratory for Mechanical Behavior of Materials, School of Materials Science and Engineering, Xi'an Jiaotong University, No. 28, Xianning West Road, Xi'an, Shaanxi Province, 710049, PR ChinaState Key Laboratory for Mechanical Behavior of Materials, School of Materials Science and Engineering, Xi'an Jiaotong University, No. 28, Xianning West Road, Xi'an, Shaanxi Province, 710049, PR ChinaState Key Laboratory for Mechanical Behavior of Materials, School of Materials Science and Engineering, Xi'an Jiaotong University, No. 28, Xianning West Road, Xi'an, Shaanxi Province, 710049, PR ChinaState Key Laboratory for Mechanical Behavior of Materials, School of Materials Science and Engineering, Xi'an Jiaotong University, No. 28, Xianning West Road, Xi'an, Shaanxi Province, 710049, PR ChinaIn this study, in–situ eutectic Mg2Si reinforced AZ61 composites unmodified and modified with Sr addition are fabricated. The effects of Sr addition on the morphology and size of Mg2Si phase, α–Mg matrix grains, its refining mechanism and mechanical properties of Mg2Si/AZ61 composites are investigated. The results show that the morphology of eutectic Mg2Si phases in Mg2Si/AZ61 composites is significantly modified from coarse Chinese character to polygonal shape with Sr addition, and Sr atoms are preferentially absorbed on the {100} surfaces of Mg2Si phase, which suppresses the preferred growth along <100> direction. Besides, some Sr atoms dissolved into the Mg2Si lattice, change the growth mode and improve its morphology. Moreover, Al4Sr formed during solidification act as the heterogeneous nucleation core of Mg2Si, to refine the size of Mg2Si from 11.37 to 2.11 μm. Meanwhile, the average size of α–Mg matrix is also refined to 50.4 μm, decreased by 49.7%, indicating that both eutectic Mg2Si phase and α–Mg grains were significantly refined by Sr addition. Compared with unmodified Mg2Si/AZ61 composite, the strength and ductility of Sr modified Mg2Si/AZ61 composites are improved simultaneously, especially the ductility increased by 63%.http://www.sciencedirect.com/science/article/pii/S2238785422002058Mg matrix compositesEutectic Mg2SiMicrostructure refinementMechanical properties
spellingShingle Yixue Dong
Peng Xiao
Yimin Gao
Qiqiang Zhao
Haocheng Yang
Microstructure refinement and mechanical properties of eutectic Mg2Si reinforced Mg matrix composites containing Sr element
Journal of Materials Research and Technology
Mg matrix composites
Eutectic Mg2Si
Microstructure refinement
Mechanical properties
title Microstructure refinement and mechanical properties of eutectic Mg2Si reinforced Mg matrix composites containing Sr element
title_full Microstructure refinement and mechanical properties of eutectic Mg2Si reinforced Mg matrix composites containing Sr element
title_fullStr Microstructure refinement and mechanical properties of eutectic Mg2Si reinforced Mg matrix composites containing Sr element
title_full_unstemmed Microstructure refinement and mechanical properties of eutectic Mg2Si reinforced Mg matrix composites containing Sr element
title_short Microstructure refinement and mechanical properties of eutectic Mg2Si reinforced Mg matrix composites containing Sr element
title_sort microstructure refinement and mechanical properties of eutectic mg2si reinforced mg matrix composites containing sr element
topic Mg matrix composites
Eutectic Mg2Si
Microstructure refinement
Mechanical properties
url http://www.sciencedirect.com/science/article/pii/S2238785422002058
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