Quantitative Study of Nonequilibrium Phase Formation by Mechanical Attrition

机械磨损非平衡相形成的定量研究

• 批准号: 9902435
• 负责人: Michael Atzmon
• 金额: $ 36.47万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-05-15 至 2003-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9902435&HistoricalAwards=false
• 关键词: Quantitative; Study; Nonequilibrium; Phase; Formation

9902435AtzmonThis is an experimental and modeling research program on nonequilibrium phase formation and stability in ball-milled metal powders. Recent experiments demonstrate the complex behavior that results from a coupling between the evolution of phases and effects of mechanical behavior. In order to gain greater understanding of this subject the influence of sample hardness and milling parameters on the effective thermodynamics of metastable alloys is investigated quantitatively. The main alloy selected for this study is nickel-silver. Characterization methods include x-ray diffraction, calorimetry, nanoindentation hardness measurements, and transmission electron microscopy. Nanoscale composition variations are investigated by a combination of analytical and high-resolution electron microscopy, taking advantage of state-of-the-art facilities. The experimental results are compared with predictions based on (1) models of effective thermodynamics and diffusion enhancement by plastic strain, and (2) quantitative data on grain size evolution during ball milling of elemental iron. %%%This research contributes to basic knowledge in the broad field of externally forced systems, overlapping with materials science, physics, chemistry and other disciplines. Significant progress is anticipated in understanding the atomistic aspects of phase formation by ball milling. Although the complexity of the ball milling process makes this fundamental study difficult, the knowledge derived on phase and microstructure design should result in significant practical benefit.***

9902435Atzmon这是一个实验和建模研究计划的非平衡相的形成和稳定性球磨金属粉末。 最近的实验表明，复杂的行为，从相的演变和力学行为的影响之间的耦合的结果。 为了更好地理解这一问题，定量研究了样品硬度和铣削参数对亚稳合金有效热力学的影响。 本研究选用的主要合金是镍银合金。 表征方法包括X射线衍射、量热法、纳米压痕硬度测量和透射电子显微镜。 纳米尺度的组成变化的分析和高分辨率电子显微镜相结合的研究，利用国家的最先进的设施。 实验结果进行了比较预测的基础上（1）有效的热力学和扩散增强塑性应变模型，（2）在球磨过程中的元素铁的晶粒尺寸演变的定量数据。 这项研究有助于在广泛的外力系统领域的基础知识，与材料科学，物理学，化学和其他学科重叠。 预计在理解球磨相形成的原子方面将取得重大进展。 虽然球磨过程的复杂性使得这项基础研究变得困难，但从相和微观结构设计中获得的知识应该会带来显着的实际效益。