A Research on Microscopic and Macroscopic Mechanics in Melting/Solidification Processes Incorporating Moving Boundary/Interface, and Its Application to Welding and Bonding

结合移动边界/界面的熔化/凝固过程的微观和宏观力学及其在焊接和粘接中的应用研究

基本信息

批准号：
10305011
负责人：
INOUE Tatsuo
金额：
$ 25.34万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

Analyses on melting and solidification processes are carried out by microscopic, macroscopic and mesoscopic viewpoints, in order to reveal the mechanism and to build up thermo-mechanical theory on the phase transformation processes incorporating moving boundary and interface, such as welding and joining. Molecular dynamics method and the finite element method are used as microscopic and macroscopic method, respectively, while phase-field method and crystal plasticity theory are applied to mesoscopic analysis. The summary is as follows :(1) Microscopic Analysis by Molecular Dynamics Method : The motions of atoms around the interface of solid and liquid are analyzed and the stability of the interface, anisotropy in the interface energy depending on crystal orientation are evaluated. And the preferred orientations of crystal growth are determined from the relation between the orientation and interface energy.(2) Mechanical Properties of Welded Heat Affected Zone : Deformation in the micro … More scopic area in the weld metal, heat-affected zone, and parent material of Mo.9Cr-1Mo steel is measured by the micro-grid method, and the relation between hardness, structural change and strain is revealed to be clear.(3) Analysis of Crystal Growth Process by Phase-Field Method : Crystal growth process is analyzed by the phase-field method in which mechanical and thermophysical properties and anisotropy based on the molecular dynamics simulation are introduced. Various modes of dendritic crystals are obtained by the combination of the parameters. These results made it possible to observe the dynamic process of the pattern formation, and some phenomena such as initial stage of crystal growth, which is difficult to experimentally observe, are demonstrated.(4) Finite Element Analysis Based on Crystal Plasticity Theory : Deformation behavior in the heat-affected zone was simulated by the finite element method, and the results obtained by the model in which grain size and anisotropy was introduced were revealed to be corresponding to experimental results. These results are supporting the relation obtained in (2). Less

从微观、宏观和细观的角度对熔化和凝固过程进行分析，以揭示其机理并建立包含移动边界和界面的相变过程（例如焊接和连接）的热机械理论。微观和宏观分别采用法和有限元法，细观分析采用相场法和晶体塑性理论：(1)微观分析。分子动力学方法：分析固体和液体界面周围的原子运动，评估界面的稳定性、取决于晶体取向的界面能量的各向异性，并根据晶体取向之间的关系确定晶体生长的优选取向。（2）焊接热影响区力学性能：Mo.9Cr-1Mo钢焊缝金属、热影响区和母材的微观区域变形为(3)相场法晶体生长过程分析：采用相场法分析晶体生长过程。引入了基于分子动力学模拟的各种模式的树枝状晶体的机械和热物理性质以及各向异性，这些结果使得观察图案形成的动态过程以及诸如此类的一些现象成为可能。晶体生长的初始阶段， (4)基于晶体塑性理论的有限元分析：采用有限元方法模拟热影响区的变形行为，并通过模型得到的结果将晶粒尺寸和各向异性考虑在内被证明与实验结果相对应，这些结果支持了（2）中获得的关系。