0905793 Voyles

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Nanodiffraction Paul M. Voyles, University of Wisconsin-Madison, DMR 0905793 The top image is an electron nanodiffraction pattern acquired with a 1.5 nm probe from a metallic glass comprised of >80% Al. Electron nanodiffraction in the scanning transmission electron microscope has the unique ability to study diffraction from only a few hundreds of atoms at a time. Based on statistical analysis of thousands of patterns, we developed a structural model for Al-based glasses, an example of which is shown in the bottom image. The model consists of ~2 nm diameter Al protocrystalline nuclei, embedded in a matrix of disordered Al, transition metal, and rare earth atoms. The protocrystalline nuclei are important because they control the crystallization behavior of Al-

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Insight into Glass Crystallization from Nanodiffraction Paul M. Voyles, University of Wisconsin-Madison, DMR 0905793. - PowerPoint PPT Presentation

Transcript of 0905793 Voyles

Page 1: 0905793 Voyles

Insight into Glass Crystallization from Nanodiffraction

Paul M. Voyles, University of Wisconsin-Madison, DMR 0905793

The top image is an electron nanodiffraction pattern acquired with a 1.5 nm probe from a metallic glass comprised of >80% Al. Electron nanodiffraction in the scanning transmission electron microscope has the unique ability to study diffraction from only a few hundreds of atoms at a time.

Based on statistical analysis of thousands of patterns, we developed a structural model for Al-based glasses, an example of which is shown in the bottom image. The model consists of ~2 nm diameter Al protocrystalline nuclei, embedded in a matrix of disordered Al, transition metal, and rare earth atoms.

The protocrystalline nuclei are important because they control the crystallization behavior of Al-based glasses and related materials, which can be used to create crystal / glass composites with exceptional strength and other desirable properties.

Page 2: 0905793 Voyles

Insight into Glass Crystallization from Nanodiffraction

Paul M. Voyles, University of Wisconsin-Madison, DMR 0905793

In order to enhance the training of the new nanotechnology workforce in advanced methods in electron microscopy, we maintain the electron microscopy database (EMdb), a free, web-based database of full bit-depth, full resolution example data sets for electron microscopy. An example record from the database is shown on the left. Each record comes with the raw data in vendor proprietary and open access formats, metadata describing the sample and acquisition conditions, and homework-style exercises for use in classroom settings or independent learning.

Since its inception, 829 users have accessed the Emdb. Many are just browsing, but 234 full datasets have been downloaded by users around the world.