共查询到19条相似文献,搜索用时 134 毫秒
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概述了目前国内外镍基单晶高温合金定向凝固数值模拟的研究进展,定向凝固过程的数值模拟由宏观向微观转变,详细介绍了微观组织数值模拟的几种主要方法:决定论方法、随机论方法和相场方法,评述了这几种方法的特点以及局限性,指出宏观和微观现象的完整耦合可以对镍基单晶高温合金凝固过程做出更加准确的模拟预测。 相似文献
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概述了目前国内外镍基单晶高温合金定向凝固数值模拟的研究进展,定向凝固过程的数值模拟由宏观向微观转变,详细介绍了微观组织数值模拟的几种主要方法:决定论方法、随机论方法和相场方法,评述了这几种方法的特点以及局限性,指出宏观和微观现象的完整耦合可以对镍基单晶高温合金凝固过程做出更加准确的模拟预测。 相似文献
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鉴于双辊薄带连铸等轴晶区半固态铸轧组织对产品性能的重要性,基于热传输、流动传输、溶质传输等基本传输过程以及晶粒生长物理过程,建立了双辊连续铸轧纯铝凝固过程的宏观温度场、浓度场、微观组织及枝晶形貌演化的三维数学模型.采用CA-FE法对双辊连续铸轧纯铝在水冷钢辊连续铸轧中的凝固过程进行了模拟,采用光学显微镜研究了铸轧工艺参数对凝固组织的影响.数值模拟结果表明,所建立的数学模型能够合理描述晶粒沿任意角度生长的过程,温度场、溶质场和微观组织形貌的模拟计算结果合理.模拟结果与实验结果基本吻合,检验了模型的正确性. 相似文献
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基于连续切片的三维重构技术在材料凝固组织研究中的应用 总被引:1,自引:1,他引:0
讨论了在材料科学与工程研究中进行三维重构的意义和必要性,介绍了基于连续切片的三维重构技术的理论、方法及在材料科学与工程中的研究和应用进展.指出基于切片的三维重构技术对材料凝固过程中微观结构定量分析、微观组织-性能的研究提供了有力支持,结合数值模拟技术可为材料凝固过程中复杂组织的形成机理及凝固理论的发展提供理论和精确的实验依据,从而对新材料的设计与开发产生重要作用.最后简要介绍了三维重构技术在定向凝固过程中多相组织分析的应用,并展望了三维重构技术的发展方向. 相似文献
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以等价比热客法处理结晶潜热和以假设的流线边界划分网格节点,建立了连续铸轧铝合金薄带凝固过程的宏观速度场、传热、溶质传输和凝固组织形成的微观数学模型以及连续铸轧铝合金薄带凝固过程的宏观-微观耦合数学模型.同时,以固相分数为媒介,采用宏微观不同的网格尺寸和时间步长,实现了宏观模型与微观模型的耦合. 相似文献
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L. Ratke S. Steinbach G. Müller M. Hainke J. Friedrich A. Roosz Y. Fautrelle M. D. Dupuoy G. Zimmermann A. Weiss J. Lacaze R. Valdes G -U. Grün H -P. Nicolai H. Gerke-Cantow 《Microgravity science and technology》2005,16(1-4):99-103
The MICAST research program focuses on a systematic analysis of the effect of convection on the microstructure evolution in cast Al-alloys. The experiments within MICAST are carried out under well defined thermally and magnetically controlled, convective boundary conditions and analyzed using advanced diagnostics and theoretical modeling, involving phase field simulation, micro-modeling and global simulation of heat and mass transport. The MICAST team uses as a model material the Al-Si base alloys. This paper gives a brief overview on recent experimental results of the MICAST team on the effect of rotating magnetic fields on microstructure in AlSi alloys. 相似文献
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This paper is devoted to the microstructure geometric modeling and mechanical
properties computation of cancellous bone. The microstructure of the cancellous bone
determines its mechanical properties and a precise geometric modeling of this structure is
important to predict the material properties. Based on the microscopic observation, a new
microstructural unit cell model is established by introducing the Schwarz surface in this
paper. And this model is very close to the real microstructure and satisfies the main
biological characteristics of cancellous bone. By using the unit cell model, the multiscale
analysis method is newly applied to predict the mechanical properties of cancellous bone.
The effective stiffness parameters are calculated by the up-scaling multi-scale analysis.
And the distribution of microscopic stress in cancellous bone is determined through the
down-scaling procedure. In addition, the effect of porosity on the stiffness parameters is
also investigated. The predictive mechanical properties are in good agreement with the
available experimental results, which verifies the applicability of the proposed unit cell
model and the validness of the multiscale analysis method to predict the mechanical
properties of cancellous bone. 相似文献
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《Current Opinion in Solid State & Materials Science》2016,20(1):37-45
The paper by Karma and Tourret (this volume) in this special issue focuses on multiscale modeling approaches ranging from atoms to microstructure. In the present one, the most recent and significant modeling contributions dealing with the scale of solidification from microstructure to grain structure are briefly reviewed. The paper also covers modeling of defect formation during the last stage of solidification, namely porosity and hot tearing. As will be shown, the field of solidification has taken advantage of several simulation and experimental tools which have become increasingly powerful and accessible over the past decade. The emphasis will be put on complex 2D and 3D models for which correlations with in situ observations using synchrotron radiation and/or combined orientation and metallography imaging have been made. 相似文献
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N. Chawla B. V. Patel M. Koopman K. K. Chawla R. Saha B. R. Patterson E. R. Fuller S. A. Langer 《Materials Characterization》2002,49(5):395-407
While it is well recognized that microstructure controls the physical and mechanical properties of a material, the complexity of the microstructure often makes it difficult to simulate by analytical or numerical techniques. In this paper we present a relatively new approach to incorporate microstructures into finite element modeling using an object-oriented finite element technique. This technique combines microstructural data in the form of experimental or simulated microstructures, with fundamental material data (such as elastic modulus or coefficient of thermal expansion of the constituent phases) as a basis for understanding material behavior. The object-oriented technique is a radical departure from conventional finite element analysis, where a “unit-cell” model is used as the basis for predicting material behavior. Instead, the starting point of object-oriented finite element analysis is the actual microstructure of the material being investigated. In this paper, an introduction to the object-oriented finite element approach to microstructure-based modeling is provided with two examples: SiC particle-reinforced Al matrix composites and double-cemented WC particle-reinforced Co matrix composites. It will be shown that object-oriented finite element analysis is a unique tool that can be used to predict elastic and thermal constants of the composites, as well as salient effects of the microstructure on local stress state. 相似文献
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《Current Opinion in Solid State & Materials Science》2016,20(1):25-36
We summarize recent advances in modeling of solidification microstructures using computational methods that bridge atomistic to continuum scales. We first discuss progress in atomistic modeling of equilibrium and non-equilibrium solid–liquid interface properties influencing microstructure formation, as well as interface coalescence phenomena influencing the late stages of solidification. The latter is relevant in the context of hot tearing reviewed in the article by M. Rappaz in this issue. We then discuss progress to model microstructures on a continuum scale using phase-field methods. We focus on selected examples in which modeling of 3D cellular and dendritic microstructures has been directly linked to experimental observations. Finally, we discuss a recently introduced coarse-grained dendritic needle network approach to simulate the formation of well-developed dendritic microstructures. This approach reliably bridges the well-separated scales traditionally simulated by phase-field and grain structure models, hence opening new avenues for quantitative modeling of complex intra- and inter-grain dynamical interactions on a grain scale. 相似文献
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I. Watanabe D. Setoyama N. Nagasako N. Iwata K. Nakanishi 《International journal for numerical methods in engineering》2012,89(7):829-845
Multiscale mechanical behaviors of ferrite–pearlite steel were predicted using numerical material testing (NMT) based on the finite element method. The microstructure of ferrite–pearlite steel is regarded as a two‐component aggregate of ferrite crystal grains and pearlite colonies. In NMT, the macroscopic stress–strain curve and the deformation state of the microstructure were examined by means of a two‐scale finite element analysis method based on the framework of the mathematical homogenization theory. The microstructure of ferrite–pearlite steel was modeled with finite elements, and constitutive models for ferrite crystal grains and pearlite colonies were prepared to describe their anisotropic mechanical behavior at the microscale level. While the anisotropic linear elasticity and the single crystal plasticity based on representative characteristic length have been employed for the ferrite crystal grains, the constitutive model of a pearlite colony was newly developed in this study. For that reason, the constitutive behavior of the pearlite colony was investigated using NMT on a smaller scale than the scale of the ferrite–pearlite microstructure, with the microstructure of the pearlite colony modeled as a lamellar structure of ferrite and cementite phases with finite elements. On the basis of the numerical results, the anisotropic constitutive model of the pearlite colony was formulated based on the normal vector of the lamella. The components of the anisotropic elasticity were estimated with NMT based on the finite element method, where the elasticity of the cementite phase was numerically evaluated with a first‐principles calculation. Also, an anisotropic plastic constitutive model for the pearlite colony was formulated with two‐surface plasticity consisting of yield functions for the interlamellar shear mode and yielding of the overall lamellar structure. After addressing the microscopic modeling of ferrite–pearlite steel, NMT was performed with the finite element models of the ferrite–pearlite microstructure and with the microscopic constitutive models for each of the components. Finally, the results were compared with the corresponding experimental results on both the macroscopic response and the microscopic deformation state to ascertain the validity of the numerical modeling. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献