Microstructural stress concentration: An important role in grain refinement of rheocasting structure

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	Microstructural stress concentration: An important role in grain refinement of rheocasting structure
	Z. Yang; C. G. Kang; Z. Q. Hu
	2005
发表期刊	Metallurgical and Materials Transactions a-Physical Metallurgy and Materials Science
ISSN	1073-5623
卷号	36A 期号:10 页码:2785-2792
摘要	Though the mechanisms of dendrite fragmentation in agitated solidification are of great importance and have been investigated for many years, no accurate calculation of the stress fields of dendrites stirred in the metallic flow has been reported. In this study, the stress field and strain field of an aluminum dendrite model in moderate agitated fluid were calculated using the finite-element method. It was found that the stress concentrations at the roots of dendrite branches are so great that plastic deformation occurs when the fluid force is far from sufficient to bend the dendrite branches plastically. According to this calculation, a mechanism, detaching after fatigue erosion, was suggested. The new mechanism suggests that stress concentrations at the roots of dendrite branches create slip band intrusions and extrusions. These slip band intrusions and extrusions are thermally unstable and are soon remelted. If the erosion rate of the roots is sufficiently large, the roots will be thinned and dendrite branches will detach. Experiments on the effects of stirring intensity, cooling rate, and stirring time on the grain sizes of the A356 rheocasting structure, and reported high-temperature fatigue tests, corroborate the effectiveness of the new mechanism.
部门归属	pusan natl univ, sch mech engn, natl res lab thixo rheo froming, pusan 609735, south korea. chinese acad sci, met res inst, shenyang natl lab mat sci, shenyang 110016, peoples r china.;yang, z (reprint author), pusan natl univ, sch mech engn, natl res lab thixo rheo froming, pusan 609735, south korea;cgkang@pusan.ac.kr
关键词	Cyclic Deformation-behavior Aluminum-alloys Semisolid State Fluid-flow Temperature Evolution Solidification Dependence Migration Metals
URL	查看原文
WOS记录号	WOS:000232076800020
引用统计	被引频次：12[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/321006/35174
专题	中国科学院金属研究所
推荐引用方式 GB/T 7714	Z. Yang,C. G. Kang,Z. Q. Hu. Microstructural stress concentration: An important role in grain refinement of rheocasting structure[J]. Metallurgical and Materials Transactions a-Physical Metallurgy and Materials Science,2005,36A(10):2785-2792.
APA	Z. Yang,C. G. Kang,&Z. Q. Hu.(2005).Microstructural stress concentration: An important role in grain refinement of rheocasting structure.Metallurgical and Materials Transactions a-Physical Metallurgy and Materials Science,36A(10),2785-2792.
MLA	Z. Yang,et al."Microstructural stress concentration: An important role in grain refinement of rheocasting structure".Metallurgical and Materials Transactions a-Physical Metallurgy and Materials Science 36A.10(2005):2785-2792.