Modeling of morphological evolution of columnar dendritic grains in the molten pool of gas tungsten arc welding

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	Modeling of morphological evolution of columnar dendritic grains in the molten pool of gas tungsten arc welding
	R. H. Han; W. C. Dong; S. P. Lu; D. Z. Li; Y. Y. Li
	2014
发表期刊	Computational Materials Science
ISSN	0927-0256
卷号	95 页码:351-361
摘要	A macro-micro coupled model for epitaxial nucleation and the subsequent competitive dendrite growth was developed to study the morphological evolution of both dendrite and grain structures in molten pool of the gas tungsten arc welding (GTAW) for Fe-C alloy. The simulation of heat and mass transfer in molten pool was conducted by the three-dimensional finite element (FE) model to obtain the transient solidification conditions. The process of epitaxial nucleation and the competitive dendrite growth was simulated by a two-dimensional cellular automata (CA) model. The size and random preferential orientations of substrate grains were considered in this model. The transient thermal conditions used in the CA model were obtained from the results of FE model through the interpolation method. In addition, the effects of the substrate grain size and the welding speed on the morphologies of both dendrite and grain structures were investigated. The simulated results indicate that dendrites with the preferential orientations parallel to the direction of the highest temperature gradient are more competitive during the competitive dendrite growth, and the morphology of resulting columnar grains is determined by the competition between different dendritic arrays. Under the same welding conditions, with the increase of substrate grain size, the average width of resulting columnar grains becomes larger, and the characteristics of dendrite structure within the columnar grains do not change obviously. Without considering the new nucleation in the melt, with the increase of welding speed, the dendrite structure in weld seam becomes much finer, and the average columnar grain width within the calculation domain of the CA model does not change obviously. The trend of the simulated results of dendrite arm spacing under various welding conditions are consistent with the analytical and experimental data. (C) 2014 Elsevier B.V. All rights reserved.
部门归属	[han, rihong ; dong, wenchao ; lu, shanping ; li, dianzhong ; li, yiyi] chinese acad sci, inst met res, shenyang natl lab mat sci, shenyang 110016, peoples r china. ; lu, sp (reprint author), chinese acad sci, inst met res, shenyang natl lab mat sci, 72 wenhua rd, shenyang 110016, peoples r china. ; shplu@imr.ac.cn
关键词	Epitaxial Nucleation Competitive Dendrite Growth Cellular Automata (Ca) Dendrite Structure Columnar Grain Welding Pool Solidification Microstructure Growth-model Gta Welds Simulation Alloys Phase Flow Orientation Prediction Parameters
URL	查看原文
语种	英语
文献类型	期刊论文
条目标识符	http://ir.imr.ac.cn/handle/321006/73236
专题	中国科学院金属研究所
推荐引用方式 GB/T 7714	R. H. Han,W. C. Dong,S. P. Lu,et al. Modeling of morphological evolution of columnar dendritic grains in the molten pool of gas tungsten arc welding[J]. Computational Materials Science,2014,95:351-361.
APA	R. H. Han,W. C. Dong,S. P. Lu,D. Z. Li,&Y. Y. Li.(2014).Modeling of morphological evolution of columnar dendritic grains in the molten pool of gas tungsten arc welding.Computational Materials Science,95,351-361.
MLA	R. H. Han,et al."Modeling of morphological evolution of columnar dendritic grains in the molten pool of gas tungsten arc welding".Computational Materials Science 95(2014):351-361.