Effect of Melt Temperature on Surface Films Formed on Molten AZ91D Alloy Protected by Graphite Powder

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	Effect of Melt Temperature 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.
	2017-12-01
发表期刊	SPRINGER
ISSN	1073-5615
卷号	48 期号:6 页码:3152-3160
摘要	Graphite powder was adopted to prevent AZ91D alloy from oxidizing during melting and casting. The microstructure of the resultant surface films, formed at 933 K, 973 K, 1013 K, and 1053 K (660 A degrees C, 700 A degrees C, 740 A degrees C, and 780 A degrees C) for 30 minutes, was investigated by scanning electron microscopy, energy dispersive spectrometer, and X-ray diffraction, and the phase composition of the surface films was analyzed by the standard Gibbs free energy change of the reactions between the graphite powder, the alloy melt, and the ambient atmosphere. The effect and mechanism of melt temperature on the resultant surface films were also discussed. The results indicated that the surface films, of which the surface morphology comprised folds and wrinkles, were composed of a protective layer and MgF2 particles. The protective layer was contributive to the prevention of the molten alloy from oxidizing, and consisted of magnesium, oxygen, fluorine, carbon, and a small amount of aluminium existing in the form of MgO, MgF2, C, and MgAl2O4. The layer thickness was 200 to 900 nm. The melt temperature may affect the surface films through the increased interaction between the graphite powder, the melt, and the ambient atmosphere. The oxygen content and thickness of the protective layer decreased and then increased, while the height of the folds increased with melt temperature.; Graphite powder was adopted to prevent AZ91D alloy from oxidizing during melting and casting. The microstructure of the resultant surface films, formed at 933 K, 973 K, 1013 K, and 1053 K (660 A degrees C, 700 A degrees C, 740 A degrees C, and 780 A degrees C) for 30 minutes, was investigated by scanning electron microscopy, energy dispersive spectrometer, and X-ray diffraction, and the phase composition of the surface films was analyzed by the standard Gibbs free energy change of the reactions between the graphite powder, the alloy melt, and the ambient atmosphere. The effect and mechanism of melt temperature on the resultant surface films were also discussed. The results indicated that the surface films, of which the surface morphology comprised folds and wrinkles, were composed of a protective layer and MgF2 particles. The protective layer was contributive to the prevention of the molten alloy from oxidizing, and consisted of magnesium, oxygen, fluorine, carbon, and a small amount of aluminium existing in the form of MgO, MgF2, C, and MgAl2O4. The layer thickness was 200 to 900 nm. The melt temperature may affect the surface films through the increased interaction between the graphite powder, the melt, and the ambient atmosphere. The oxygen content and thickness of the protective layer decreased and then increased, while the height of the folds increased with melt temperature.
部门归属	[li, weihong ; zhou, jixue ; wu, jianhua] shandong acad sci, adv mat inst, shandong key lab high strength lightweight metall, jinan 250014, shandong, peoples r china ; [ma, baichang ; wang, jinwei] shandong acad sci, adv mat inst, shandong engn res ctr lightweight automobiles mag, jinan 250014, shandong, peoples r china ; [yang, yuansheng] chinese acad sci, inst met res, shenyang 110016, liaoning, peoples r china
学科领域	Materials Science, Multidisciplinary ; Metallurgy & Metallurgical Engineering
资助者	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]
收录类别	SCI
语种	英语
WOS记录号	WOS:000415806100031
引用统计	被引频次：1[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://ir.imr.ac.cn/handle/321006/78956
专题	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 Melt Temperature on Surface Films Formed on Molten AZ91D Alloy Protected by Graphite Powder[J]. SPRINGER,2017,48(6):3152-3160.
APA	Li, Weihong.,Zhou, Jixue.,Ma, Baichang.,Wang, Jinwei.,Wu, Jianhua.,...&Li, WH .(2017).Effect of Melt Temperature on Surface Films Formed on Molten AZ91D Alloy Protected by Graphite Powder.SPRINGER,48(6),3152-3160.
MLA	Li, Weihong,et al."Effect of Melt Temperature on Surface Films Formed on Molten AZ91D Alloy Protected by Graphite Powder".SPRINGER 48.6(2017):3152-3160.