Statistical Mechanics of Microstructural Evolution

微观结构演化的统计力学

• 批准号: 9633346
• 负责人: Martin Glicksman
• 金额: $ 35.48万
• 依托单位: Rensselaer Polytechnic Institute
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-08-15 至 2000-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9633346&HistoricalAwards=false
• 关键词: Statistical; Mechanics; Microstructural; Evolution

9633346 Glicksman This study is directed toward developing a firm experimental basis and deeper understanding of microstructural evolution in two-phase alloys. The focus is to integrate and test several theories that describe microstructural coarsening kinetics. Specifically, "snap-shot" calculations, based on distributions of point sources and sinks to represent diffusional interactions in dilute microstructures, are extended to higher volume fractions. Kinetic studies on binary alloys are pursued which are found to exhibit temporal exponents in ultra-dense microstructures that, curiously, decrease from the classical Ostwald ripening value of 1/3 to a value of 1/4. This is attributed to an as yet unexplained kinetic behavior from the influence of particle shape accommodation and strong spatial correlations. In summary, the research focuses both theoretical and experimental efforts on integrating and validating fundamental elements of coarsening theory to achieve progress toward a more unified kinetic description of microstructure evolution over the volume fraction range 0- 1. %%% The core subjects of this grant include determining kinetic laws for alloys processed over the full range of compositions and explaining them through basic kinetic principles. Properties of metal alloys depend on their microstructure, and the microstructural behavior depends primarily on time, temperature, and composition. Temperature controls the rate of atom diffusion, whereas, at a fixed temperature, the average chemical composition determines the volume fraction of dispersed phases, and, indirectly, establishes the microstructural length scales for diffusion and interfacial processes. ***

9633346 Glicksman 这项研究旨在为两相合金的微观结构演变奠定坚实的实验基础并加深理解。 重点是整合和测试描述微观结构粗化动力学的几种理论。 具体来说，基于点源和汇的分布来表示稀微结构中的扩散相互作用的“快照”计算被扩展到更高的体积分数。 对二元合金进行了动力学研究，发现其在超致密微观结构中表现出时间指数，奇怪的是，该指数从经典奥斯特瓦尔德熟化值 1/3 降低到 1/4。 这是由于颗粒形状调节和强空间相关性的影响而导致的尚未解释的动力学行为。 总之，该研究的重点是理论和实验工作，整合和验证粗化理论的基本要素，以实现对体积分数范围 0-1 内微观结构演化的更统一的动力学描述。%%% 这项资助的核心主题包括确定在整个成分范围内加工的合金的动力学定律，并通过基本动力学原理对其进行解释。 金属合金的性能取决于其微观结构，而微观结构行为主要取决于时间、温度和成分。 温度控制原子扩散速率，而在固定温度下，平均化学成分决定分散相的体积分数，并间接确定扩散和界面过程的微观结构长度尺度。 ***