Powder-Based Dealloying

非技术概述新金属的发现和设计涉及到在微观尺度上控制材料的成分和结构。通过这种控制，可以制造出适用于许多不同应用的更好的材料，从结构材料到催化剂再到电池，再到具有高辐射损伤耐受性的材料。这个项目正在研究一种新的方法来制造这些下一代金属和金属纳米结构，混合了来自粉末冶金和一种名为脱合金化的外来材料加工技术的灵感。当固体金属中的一种元素被从金属中拉出，留下纳米孔材料时，就会发生去合金化。这项工作的中心假设是，粉末混合物可以用来制造非合金材料。一种粉末成分起到吸收从另一种粉末成分中脱出的元素的作用。由于使用的是粉末，预计大量的加工材料可以很容易地制造出来，并随时进行测试，以满足不同的应用。本科生和研究生阶段的学生培训将有助于培养受过现代冶金培训的下一代材料科学家。除上述培训外，还将组织和参加有关脱合金化和相关专业发展的国际会议。技术概述纳米复合材料和纳米多孔金属由多个相互渗透但成分截然不同的固体和空心相组成，有望用于需要高强度、高延展性、耐辐射、催化、传感、超级电容器、电池的结构应用，以及作为模板通过回填制造新的纳米复合材料。制造这种材料的一种技术是去合金化--从多组分的合金中选择性地溶解一种组分。该项目探索下一代非合金化纳米结构材料，使用一种被称为基于粉末的脱合金化的概念。粉基脱合金是指在混合粉末环境中的冶金相演变，其中一种粉末的成分是要脱合金的材料，另一种粉末在熔化时起到脱合金介质的作用。这涉及到对固定体积的脱合金化动力学的分析，并假设可以制造出具有特征长度小于50 nm的非常精细的微观结构的大块金属样品。我们还在采取第一步，评估如何将去合金化整合到粉末冶金加工方法中，并可能最终整合到添加剂制造中。通过研究一系列粉末脱合金化制备的模型材料，将开发一个基本物理动力学行为数据库，该数据库将适用于从烧结到添加剂制造的许多高温加工技术，以及更有效地处理稀有、难以维持和耐火的材料。本科生和研究生阶段的学生培训将有助于培养受过现代冶金培训的下一代材料科学家。这种培训将通过组织和参加关于脱合金和相关专业发展的国际会议来补充。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Non-Technical SummaryThe discovery and design of new metals involves controlling material composition and structure at the microscale. By such control, better materials can be made for many different applications, from structural materials to catalysts to batteries, and to materials with high tolerance to radiation damage. This program is examining a new approach to making these next-generation metals and metallic nanostructures, mixing inspiration from powder metallurgy and from an exotic materials processing technique called dealloying. Dealloying occurs when one element of a solid metal is pulled out of the metal, leaving behind a nanoporous material. The central hypothesis of this work, is that a powder mixture can be used to create dealloyed materials. One powder component acts to absorb elements dealloyed from the other. Because powders are being used, it is expected that bulk amounts of processed materials can be made easily and readily tested for different applications. Student training at the undergraduate and graduate levels will help develop the next generation of materials scientists trained in modern metallurgy. Such training will be complemented by organizing and participating in international conferences on dealloying and related professional development.Technical SummaryNanocomposite and nanoporous metals consisting of multiple interpenetrating but compositionally distinct solid and void phases hold promise for structural applications requiring high strength, high ductility, radiation tolerance, catalysis, sensing, supercapacitors, batteries, and as templates to make new nanocomposites via backfilling. A technique to make such materials is dealloying - the selective dissolution of one component from a multi-component alloy. This project explores the next-generation of dealloyed nanostructured materials, using a concept called powder-based dealloying. Powder-based dealloying refers to the metallurgical phase evolution in the environment of mixed powders, where the composition of one powder is the material to be dealloyed, and the other powder, when melted, acts as the dealloying medium. This involves analysis of the kinetics of dealloying in fixed volumes, and it is hypothesized that bulk samples of metals can be made that exhibit very fine microstructures with characteristic lengths less than 50 nm. We are also taking the first steps to assess how dealloying can be integrated into powder metallurgical processing methods, and perhaps ultimately additive manufacturing. By examining a range of model materials made by powder-based dealloying, a database of basic physical kinetics behavior will be developed that will be applicable to many high-temperature processing technologies, from sintering to additive manufacturing, as well as more efficiently work with rare, hard-to-sustain, and refractory materials. Student training at the undergraduate and graduate levels will help develop the next generation of materials scientists trained in modern metallurgy. Such training will be complemented by organizing and participating in international conferences on dealloying and related professional development.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.