Wetting Transitions in Liquid and Solid Alloys

液体和固体合金中的润湿转变

• 批准号: 9820169
• 负责人: Paul Wynblatt
• 金额: $ 42万
• 依托单位: Carnegie-Mellon University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-04-01 至 2003-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9820169&HistoricalAwards=false
• 关键词: Wetting; Transitions; Liquid; Solid; Alloys

9820169WynblattThis research consists of two principal thrusts. The first thrust focuses on the study of wetting transitions in liquid alloys. This is a natural extension of work performed under a previous NSF grant on two-phase liquid Ga-Pb alloys in which complete wetting of the Ga-rich phase by the Pb-rich phase was demonstrated. The approaches to be used in this study include measurement of liquid alloy surface energies by means of the sessile drop technique, coupled with direct measurements of adsorption at the liquid surfaces by Auger electron spectroscopy (AES). In addition, the gravitational thinning of the (denser) Pb-rich liquid layer at the surface of the (less dense) Ga-rich liquid phase is investigated in binary Ga-Pb alloys. This is accomplished by AES measurements of the thickness of the Pb layer as a function of liquid drop height. The second thrust of the research addresses wetting transitions in solid two-phase alloys. No previous work on wetting transitions has been reported in solid binary alloys. The Au-Ni system is identified as one in which a transition in wetting of the Ni-rich phase by the Au-rich phase is likely to take place. The wetting transition is investigated by studying the associated Au adsorption (segregation) phenomena at the surface of the Ni-rich phase. The adsorption of Au at the surfaces of single-phase Ni-rich alloys is studied as samples are cooled towards the miscibility gap, where Au-rich and Ni-rich phases coexist. The adsorption behavior of Au is expected to be quite different at temperatures above and below the wetting temperature.%%%Whereas a great deal of research has been performed over the past several years to develop improved fundamental understanding of wetting transitions, most of this work has focused on wetting transitions in liquid organic mixtures, or in adsorbed noble gases. In contrast, little research has been devoted to the nature of these phenomena in metallic alloys, where the interactions are quite different. Thus this research has a potential for leading to exciting new science. In addition, the selected alloys represent a large class of technologically interesting materials. For instance, the study of wetting phenomena is clearly important in developing better fundamental understanding of solid and liquid phase sintering, of liquid metal joining processes, of metal refining, and of liquid metal embrittlement.***

9820169 Wynblatt这项研究包括两个主要的推动力。 第一个重点是研究液态合金中的润湿转变。 这是一个自然的延伸，根据先前的NSF授予两相液体镓铅合金，其中富镓相的富铅相的完全润湿进行的工作被证明。 在这项研究中使用的方法包括测量液体合金的表面能的座滴技术的装置，再加上在液体表面的俄歇电子能谱（AES）的吸附的直接测量。 此外，重力减薄的（较密集的）富铅的液体层的（较不密集的）富镓液相的表面上的二元Ga-Pb合金进行了研究。 这是通过作为液滴高度的函数的Pb层的厚度的AES测量来实现的。 研究的第二个重点是解决固体两相合金中的润湿转变。 以前没有关于固体二元合金润湿转变的研究报道。 Au-Ni系统被确定为一个过渡的富Ni相的富Au相的润湿是可能发生的。 润湿转变的研究通过研究相关的Au的吸附（偏析）现象在表面的富Ni相。 研究了Au在单相富Ni合金表面的吸附，当样品冷却到富Au和富Ni相共存的可熔性间隙时。 Au的吸附行为预计在高于和低于润湿温度的温度下会有很大的不同。%而大量的研究已经进行了在过去几年中，发展改善润湿转变的基本理解，大多数这项工作集中在液体有机混合物中的润湿转变，或在吸附的惰性气体。 相比之下，很少有研究致力于这些现象的性质在金属合金，其中的相互作用是完全不同的。 因此，这项研究有可能导致令人兴奋的新科学。 此外，所选合金代表了一大类技术上令人感兴趣的材料。 例如，润湿现象的研究对于更好地理解固相和液相烧结、液态金属连接过程、金属精炼和液态金属脆化显然是重要的。