Solidification Behavior and Microstructure of Al-7Si Alloys with Individual and Combined Additions of Sr and Yb

The effects of individual and combined additions of Sr and Yb on the solidification behavior and microstructure of Al-7Si alloys were investigated using thermal analysis, optical microscopy, and scanning electron microscopy. The results showed that the nucleation temperature, minimum temperature, an...

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Main Authors: Zhou Dong, Zhi Hu, Hong Yan, Hecong Xie, Xiao Li
Format: Article
Language:English
Published: Wiley 2019-01-01
Series:Advances in Materials Science and Engineering
Online Access:http://dx.doi.org/10.1155/2019/9750526
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author Zhou Dong
Zhi Hu
Hong Yan
Hecong Xie
Xiao Li
author_facet Zhou Dong
Zhi Hu
Hong Yan
Hecong Xie
Xiao Li
author_sort Zhou Dong
collection DOAJ
description The effects of individual and combined additions of Sr and Yb on the solidification behavior and microstructure of Al-7Si alloys were investigated using thermal analysis, optical microscopy, and scanning electron microscopy. The results showed that the nucleation temperature, minimum temperature, and growth temperature of eutectic solidification were lower than those of the unmodified alloys, and eutectic recalescence at 2°C in the Yb- and (Sr + Yb)-modified alloys was observed. The decrease in the nucleation temperature and an increase in recalescence obviously refined the eutectic Si morphology of the Sr-, Yb-, and (Sr + Yb)-modified alloys from a coarse plate-like structure to a fine fibrous structure. Moreover, the three-dimensional microstructure of eutectic Si in the (Sr + Yb)-modified alloy showed the finer fibrous structure, which was mainly attributed to formation of the Al2Si2Yb phase. The formation enthalpy of Al2Si2Yb was lower than that of Al-(Si)-Sr in the (Sr + Yb)-modified alloy, thus suppressing the formation of the Al2Si2Sr intermetallic compound. The more effective Sr together with Yb further improved the modification effect of eutectic silicon.
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spelling doaj-art-cf629eac2b3a4da791446b7fa560f0d62025-08-20T03:23:43ZengWileyAdvances in Materials Science and Engineering1687-84341687-84422019-01-01201910.1155/2019/97505269750526Solidification Behavior and Microstructure of Al-7Si Alloys with Individual and Combined Additions of Sr and YbZhou Dong0Zhi Hu1Hong Yan2Hecong Xie3Xiao Li4Institute of Advanced Forming, Nanchang University, Nanchang 330031, ChinaInstitute of Advanced Forming, Nanchang University, Nanchang 330031, ChinaInstitute of Advanced Forming, Nanchang University, Nanchang 330031, ChinaInstitute of Advanced Forming, Nanchang University, Nanchang 330031, ChinaInstitute of Advanced Forming, Nanchang University, Nanchang 330031, ChinaThe effects of individual and combined additions of Sr and Yb on the solidification behavior and microstructure of Al-7Si alloys were investigated using thermal analysis, optical microscopy, and scanning electron microscopy. The results showed that the nucleation temperature, minimum temperature, and growth temperature of eutectic solidification were lower than those of the unmodified alloys, and eutectic recalescence at 2°C in the Yb- and (Sr + Yb)-modified alloys was observed. The decrease in the nucleation temperature and an increase in recalescence obviously refined the eutectic Si morphology of the Sr-, Yb-, and (Sr + Yb)-modified alloys from a coarse plate-like structure to a fine fibrous structure. Moreover, the three-dimensional microstructure of eutectic Si in the (Sr + Yb)-modified alloy showed the finer fibrous structure, which was mainly attributed to formation of the Al2Si2Yb phase. The formation enthalpy of Al2Si2Yb was lower than that of Al-(Si)-Sr in the (Sr + Yb)-modified alloy, thus suppressing the formation of the Al2Si2Sr intermetallic compound. The more effective Sr together with Yb further improved the modification effect of eutectic silicon.http://dx.doi.org/10.1155/2019/9750526
spellingShingle Zhou Dong
Zhi Hu
Hong Yan
Hecong Xie
Xiao Li
Solidification Behavior and Microstructure of Al-7Si Alloys with Individual and Combined Additions of Sr and Yb
Advances in Materials Science and Engineering
title Solidification Behavior and Microstructure of Al-7Si Alloys with Individual and Combined Additions of Sr and Yb
title_full Solidification Behavior and Microstructure of Al-7Si Alloys with Individual and Combined Additions of Sr and Yb
title_fullStr Solidification Behavior and Microstructure of Al-7Si Alloys with Individual and Combined Additions of Sr and Yb
title_full_unstemmed Solidification Behavior and Microstructure of Al-7Si Alloys with Individual and Combined Additions of Sr and Yb
title_short Solidification Behavior and Microstructure of Al-7Si Alloys with Individual and Combined Additions of Sr and Yb
title_sort solidification behavior and microstructure of al 7si alloys with individual and combined additions of sr and yb
url http://dx.doi.org/10.1155/2019/9750526
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