Using a powerful electron microscope to view atomic-level details, Johns Hopkins researchers have discovered a "twinning" phenomenon in a nanocrystalline form of aluminum that was plastically deformed during lab experiments. The finding will help scientists better predict the mechanical behavior and reliability of new types of specially fabricated metals. The research results, an important advance in the understanding of metallic nanomaterials, were published in a recent issue of the journal Science.
At the microscopic level, most metals are made up of tiny crystallites, or grains. Through careful lab processing, however, scientists in recent years have begun to produced nanocrystalline forms of metals in which the individual grains are much smaller. These nanocrystalline forms are prized because they are much stronger and harder than their commercial-grade counterparts. Although they are costly to produce in large quantities, these nanomaterials can be used to make critical components for tiny machines called microelectromechanical systems, often referred to as MEMS, or even smaller nanoelectromechanical systems, NEMS.
But before they build devices with nanomaterials, engineers need a better idea of how the metals will behave. For example, under what conditions will they bend or break? To find out what happens to these new metals under stress at the atomic level, Johns Hopkins researchers, led by Mingwei Chen, conducted experiments on a thin film of nanocrystalline aluminum. Grains in this form of aluminum are 1,000th the size of the grains in commercial aluminum.
Phil Sneiderman | EurekAlert!
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The operational speed of semiconductors in various electronic and optoelectronic devices is limited to several gigahertz (a billion oscillations per second). This constrains the upper limit of the operational speed of computing. Now researchers from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg, Germany, and the Indian Institute of Technology in Bombay have explained how these processes can be sped up through the use of light waves and defected solid materials.
Light waves perform several hundred trillion oscillations per second. Hence, it is natural to envision employing light oscillations to drive the electronic...
Most natural and artificial surfaces are rough: metals and even glasses that appear smooth to the naked eye can look like jagged mountain ranges under the microscope. There is currently no uniform theory about the origin of this roughness despite it being observed on all scales, from the atomic to the tectonic. Scientists suspect that the rough surface is formed by irreversible plastic deformation that occurs in many processes of mechanical machining of components such as milling.
Prof. Dr. Lars Pastewka from the Simulation group at the Department of Microsystems Engineering at the University of Freiburg and his team have simulated such...
Investigation of the temperature dependence of the skyrmion Hall effect reveals further insights into possible new data storage devices
The joint research project of Johannes Gutenberg University Mainz (JGU) and the Massachusetts Institute of Technology (MIT) that had previously demonstrated...
Researchers at Chalmers University of Technology, Sweden, recently completed a 5-year research project looking at how to make fibre optic communications systems more energy efficient. Among their proposals are smart, error-correcting data chip circuits, which they refined to be 10 times less energy consumptive. The project has yielded several scientific articles, in publications including Nature Communications.
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After helping develop a new approach for organic synthesis -- carbon-hydrogen functionalization -- scientists at Emory University are now showing how this approach may apply to drug discovery. Nature Catalysis published their most recent work -- a streamlined process for making a three-dimensional scaffold of keen interest to the pharmaceutical industry.
"Our tools open up whole new chemical space for potential drug targets," says Huw Davies, Emory professor of organic chemistry and senior author of the paper.
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