MRI: Acquisition of a Dual Beam Plasma Focused Ion Beam Scanning Electron Microscope to Accelerate the Materials Characterization

非技术这个项目使用了一种新的显微镜，它代表了材料表征方面的一项突破。这种新的显微镜被称为氙气等离子体聚焦离子束显微镜，研究团队正在使用它来可视化不透明材料的三维体积的内部结构和化学成分，分辨率在纳米范围内。首次有可能测量先进陶瓷、高性能合金、固体氧化物燃料电池和磁存储器件中的大量结构特征。重要的贡献是超越了孤立的观察，我们不仅用平均或有代表性的内部结构来描述材料的性质，而且还用微观结构中的罕见事件(大偏差)来描述材料的性质。新的显微镜不仅加速了卡内基梅隆大学的研究，也加快了该地区研究机构和行业的研究。数十名研究生和本科生将在卡内基梅隆大学接受使用这种乐器的培训。通过一年一度的三维材料科学暑期学校为更大的研究界提供培训，并通过两个基于网络的储存库--三维材料图集和颗粒边界数据档案--提供该仪器的研究成果。技术本研究中采用的氙等离子体聚焦离子束显微镜使以纳米级精度以高度受控的方式对表面成像并从同一表面去除材料成为可能，但速度比现有仪器快50倍。高去除效率的关键是等离子体离子源，它可以获得比传统液态金属源更高的束流。这使得有可能在整个大体积中进行三维成像实验，并对埋藏在样品深处的特征进行特定部位的分析(通过透射电子显微镜或原子探针断层扫描)，而传统的液态金属源显微镜无法接触到这些特征。该项目的目标是制备具有特殊几何形状的样品，用于在操作条件下通过透射电子显微镜对电子器件进行成像，用于高通量测量晶界迁移率，研究复杂的离子转变，用于测量工程材料的晶界特征和能量分布，以及研究缺陷类型对高性能合金应力腐蚀破裂的影响。

AbstractNon-technicalThis project uses a new microscope that represents a breakthrough in materials characterization. The new microscope, referred to as a xenon plasma focused ion beam microscope, is being used by the research team to visualize the internal structure and chemical composition of three-dimensional volumes of opaque material with a resolution in the range of nanometers. For the first time, it is possible to measure a large number of structural features in advanced ceramics, high performance alloys, solid oxide fuel cells, and magnetic memory devices. The important contribution is to move beyond isolated observations to a point where we describe materials properties not only in terms of the average or representative internal structure, but also in terms of rare events (large deviations) in the microstructure. The new microscope accelerates research not only at Carnegie Mellon, but also at research institutions and industries in the region. Dozens of graduate and undergraduate students will be trained to use the instrument at Carnegie Mellon. Training for the larger research community is provided through an annual three-dimensional materials science summer school and findings from the instrument are being made available through two web-based repositories: the Three-Dimensional Materials Atlas and the Grain Boundary Data Archive.TechnicalThe xenon plasma focused ion beam microscope deployed in this research has made it possible to both image surfaces and to remove material from the same surfaces in a highly controlled fashion with nano-scale precision, but 50 times faster than with pre-existing instruments. The key to high removal rates is the plasma ion source, which can achieve higher beam currents than the conventional liquid metal sources. This has made it possible to conduct three-dimensional imaging experiments throughout large volumes and conduct site-specific analysis (by transmission electron microscopy or atom probe tomography) of features buried deep within a specimen that are not accessible to conventional liquid metal source microscopes. The project's goals are to prepare samples with specialized geometries for imaging electronic devices under operating conditions by transmission electron microscopy, for high-throughput measurements of grain boundary mobility to study complex ion transitions, for the measurement of the grain boundary character and energy distributions of engineering materials, and for studying the influence of flaw types on stress corrosion cracking in high performance alloys.