Effect of Holding Time on Surface Films Formed on Molten AZ91D Alloy Protected by Graphite Powder

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	Effect of Holding Time on Surface Films Formed on Molten AZ91D Alloy Protected by Graphite Powder
	Li, Weihong; Zhou, Jixue; Ma, Baichang; Wang, Jinwei; Wu, Jianhua; Yang, Yuansheng; Li, WH (reprint author), Shandong Acad Sci, Adv Mat Inst, Shandong Key Lab High Strength Lightweight Metall, Jinan 250014, Shandong, Peoples R China.
刊名	SPRINGER
	2017-10-01
卷号	48 期号:5 页码:2334-2342
ISSN号	1073-5615
英文摘要	Graphite powder was adopted to prevent the AZ91D magnesium alloy from oxidizing during the melting and casting process. The microstructure of the resultant surface films formed at 973 K (700 A degrees C) holding for 0, 15, 30, 45, and 60 minutes was investigated by scanning electron microscopy, energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) after mechanical polishing and chemical etching. The results indicated that the surface films were composed of a protective layer and the underneath particles with different morphology. The protective layer was continuous with a thickness of 200 to 1000 nm mainly consisting of MgO, MgF2, and C, while the underneath particles mainly consisted of MgF2 and MgAl2O4. The surface films were the result of the interaction between the graphite powder, the melt, and the ambient atmosphere. The number and the size of the underneath particles, determining the thickness uniformity of the surface films, and the unevenness of the microsurface morphology increased with holding time. The mechanism of holding time on the resultant surface films was also discussed.; Graphite powder was adopted to prevent the AZ91D magnesium alloy from oxidizing during the melting and casting process. The microstructure of the resultant surface films formed at 973 K (700 A degrees C) holding for 0, 15, 30, 45, and 60 minutes was investigated by scanning electron microscopy, energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) after mechanical polishing and chemical etching. The results indicated that the surface films were composed of a protective layer and the underneath particles with different morphology. The protective layer was continuous with a thickness of 200 to 1000 nm mainly consisting of MgO, MgF2, and C, while the underneath particles mainly consisted of MgF2 and MgAl2O4. The surface films were the result of the interaction between the graphite powder, the melt, and the ambient atmosphere. The number and the size of the underneath particles, determining the thickness uniformity of the surface films, and the unevenness of the microsurface morphology increased with holding time. The mechanism of holding time on the resultant surface films was also discussed.
学科主题	Materials Science, Multidisciplinary ; Metallurgy & Metallurgical Engineering
语种	英语
资助机构	National Key Research and Development Program of China [2016YFB0701202, 2016YFB0301105]; Natural Science Foundation of Shandong Province [ZR2016EMB11, ZR2015YL007]; Youth Foundation of Shandong Academy of Sciences [2014QN024]
公开日期	2018-01-10
内容类型	期刊论文
源URL	[http://ir.imr.ac.cn/handle/321006/79078]
专题	金属研究所_中国科学院金属研究所
通讯作者	Li, WH (reprint author), Shandong Acad Sci, Adv Mat Inst, Shandong Key Lab High Strength Lightweight Metall, Jinan 250014, Shandong, Peoples R China.
推荐引用方式 GB/T 7714	Li, Weihong,Zhou, Jixue,Ma, Baichang,et al. Effect of Holding Time on Surface Films Formed on Molten AZ91D Alloy Protected by Graphite Powder[J]. SPRINGER,2017,48(5):2334-2342.
APA	Li, Weihong.,Zhou, Jixue.,Ma, Baichang.,Wang, Jinwei.,Wu, Jianhua.,...&Li, WH .(2017).Effect of Holding Time on Surface Films Formed on Molten AZ91D Alloy Protected by Graphite Powder.SPRINGER,48(5),2334-2342.
MLA	Li, Weihong,et al."Effect of Holding Time on Surface Films Formed on Molten AZ91D Alloy Protected by Graphite Powder".SPRINGER 48.5(2017):2334-2342.