RUI: Morphology and Crystalline Orientation of Particles in Al65Cu20Fe15 Alloy Prepared by Arc Melting

非技术概要：晶体结构和非晶态结构在固体中的原子构型方面处于两个极端。在晶体结构中，原子按照预定的规则排列，而在非晶结构中，原子以随机的方式排列。准晶结构可以认为是介于两者之间的一种状态。以黄金和窗户玻璃为代表的晶体和非晶态结构的材料，已经为人类所知数千年了。相比之下，准晶结构材料在20世纪80年代才被发现，还有许多方面有待研究。Al65Cu20Fe15组成的铝铜铁合金是研究最多的准晶相合金之一。这种合金，当它是电弧熔化制备时，是多孔的，由多个空洞组成，表面上有不同形态的颗粒。尽管之前进行了广泛的研究，但对于这些颗粒的组成和形成过程仍有许多不同的看法，可能是因为之前的研究没有将重点放在它们上。此外，现任首席研究员对这些粒子的初步研究揭示了值得进一步研究的新细节。本项目将对这些粒子进行详细的研究。除了科学贡献外，该项目还对Clarion大学这所乡村教学学院的教育产生了重大影响。首先，它使首席研究员能够在研究领域保持活跃，并将最新发展融入教学。其次，它给学生一个难得的机会去体验或观察真实的科学研究，增强他们追求科学技术事业的信心。每年，该项目将以以下方式接触到学生：8名本科生将作为带薪研究助理或志愿者参与该项目；两名当地高中生将有机会在夏季用一周的时间来完成这个项目；约100名本科生将在课程教学中通过介绍接触到该项目；附近一所高中的感兴趣的学生将被邀请到校园，从主要研究者和本科生那里了解这个项目。技术总结：在制备的Al65Cu20Fe15合金的孔洞表面，确定了六个与颗粒形貌和晶体取向有关的重要问题，这些问题要么是以前没有报道过的，要么是没有得到很好的理解。例如，有强有力的证据表明，一种粒子由多个相组成，而不是以前的单相假设。已有实验结果推测准晶薄膜与晶体衬底之间的取向关系，有待进一步证实和研究。这些问题将在实验中通过配备能量色散x射线光谱学（EDS）和电子后向散射衍射（EBSD）的扫描电子显微镜（SEM）来澄清，该实验将在首席研究员的家庭研究所进行。这些研究将辅以理论分析和透射电子显微镜（TEM）检查，并将与其他研究所合作进行。由于该项目清晰而独特的焦点，该项目将产生足够的数据来填补缺失的细节，并澄清关于这种知名合金的微观结构的相互矛盾的报道，从而建立一个可靠和一致的相形成过程模型。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Non-Technical Summary:Crystalline and amorphous structures stand in two extremes in term of atomic configuration in solids. In a crystalline structure, atoms are arranged according to predefined rules while in amorphous structures atoms are packed in random fashion. Quasicrystalline structure can be considered as a state between the two. Materials of crystalline and amorphous structures, represented by gold and window glass, respectively, have been known to mankind for thousands of years. In contrast, materials of quasicrystalline structure were recently discovered in 1980's, and many aspects remain to be studied. An aluminum-copper-iron alloy of Al65Cu20Fe15 composition is one of the most studied alloys related to quasicrystalline phase. This alloy, when it is prepared by arc melting, is porous, consisting of multiple voids with particles of different morphologies on the surface. Despite previous extensive studies, there are many different opinions about the make-up and formation processes of these particles, probably because no previous studies have placed focus on them. Further, a primary study of these particles by the present principal investigator has revealed new details that deserve further investigation. This project will carry out a detailed study on these particles. In addition to scientific contribution, the project has significant impact on the education at Clarion University, a rural teaching college. First, it enables the principal investigator to stay active in research field and to integrate latest developments into teaching. Second, it gives students a rare opportunity to experience or observe authentic scientific research, strengthening their confidence in pursuing careers in science and technology. Annually, the project will reach students in the following ways: eight undergraduate students will work on the project either as paid research assistants or as volunteers; two local high school students will be given opportunity to work on the project for a week in summer; approximately 100 undergraduate students will be exposed to the project through introduction in course teaching; and interested students from one neighboring high school will be invited to campus to learn about the project from principal investigator and undergraduate students. Technical Summary:Six important problems related to the morphology and crystal orientation of particles on the surface of the voids of as-prepared Al65Cu20Fe15 alloy have been identified, which have either not been reported previously or have not been well understood. For example, there is strong evidence indicating that one type of particle consists of multiple phases, in contrast to previous single phase assumption. There are experimental results that lead to a speculation about the orientation relationship between quasicrystalline thin film and crystalline substrate, which needs to be confirmed and investigated further. These problems will be clarified experimentally by using a Scanning Electron Microscope (SEM) equipped with Energy Dispersive X-ray Spectroscopy (EDS) and Electron Backscattering Diffraction (EBSD), to be carried out at the principal investigator's home institute. The studies will be supplemented by theoretical analysis and Transmission Electron Microscope (TEM) examinations to be performed in collaboration with other institutes. Because of the clear and unique focus, this project will generate sufficient data to fill in the missing details and to clarify conflicting reports about the microstructure of this well-known alloy, thus establishing a reliable and consistent model about the phase formation process.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.