Solid-State Alloying and Amorphization of Immiscible Elements

难混溶元素的固态合金化和非晶化

• 批准号: 9613865
• 负责人: En (Evan) Ma
• 金额: $ 10.16万
• 依托单位: Louisiana State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-03-01 至 1998-09-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9613865&HistoricalAwards=false
• 关键词: Solid; State; Alloying; Amorphization; Immiscible

9613865 Ma This research deals with metallic alloys that are far removed from equilibrium, namely amorphous alloys and supersaturated nanocrystalline solid solutions. The focus is on metastable phase formation using solid-state processing techniques in binary systems characterized by a large positive heat of mixing. A systematic experimental approach should lead to clearer understanding of the formation of metastable phases and their transformations in immiscible systems. Scientific areas explored include the mechanisms responsible for amorphization observed in some mechanically-alloyed binary immiscible systems; limitations to the extent of alloying in such systems; the degree of stability in these metastable phases; the degree of short range clustering; and the similarities and differences in thermodynamic behavior of immiscible alloys prepared through different solid-state techniques. Measurement techniques employed include calorimetry, transmission electron microscopy, thermodynamic modeling, and extended X-ray absorption fine structure analysis. %%% Development of the fundamentals of thermodynamic and kinetic phenomena of immiscible alloy systems is needed to understand their synthesis, structure, and stability. ***

小行星9613865 这项研究涉及远离平衡的金属合金，即非晶合金和过饱和纳米晶固溶体。 重点是亚稳相的形成，其特征在于由一个大的正混合热的二元系统中使用固态加工技术。 一个系统的实验方法应导致更清楚地了解亚稳相的形成和它们在不混溶系统中的转化。 探索的科学领域包括负责在一些机械合金化的二元不混溶系统中观察到的非晶化的机制;在这种系统中合金化程度的限制;这些亚稳相的稳定程度;短程聚类的程度;以及通过不同的固态技术制备的不混溶合金的热力学行为的相似性和差异。 所采用的测量技术包括量热法、透射电子显微镜、热力学建模和扩展X射线吸收精细结构分析。 发展不混溶合金系统的热力学和动力学现象的基本原理是理解它们的合成、结构和稳定性所必需的。 ***