Tag Archives: mechanical properties

Molecular Scientists Reveal Extraordinary Properties of Ordinary Glasses

Technologically valuable ultrastable glasses can be produced in days or hours with properties corresponding to those that have been aged for thousands of years, computational and laboratory studies have confirmed.

Aging makes for higher quality glassy materials because they have slowly evolved toward a more stable molecular condition. This evolution can take thousands or millions of years, but manufacturers must work faster. Armed with a better understanding of how glasses age and evolve, researchers at the universities of Chicago and Wisconsin-Madison raise the possibility of designing a new class of materials at the molecular level via a vapor-deposition process. (more…)

Read More

Nanocrystals Not Small Enough to Avoid Defects

Berkeley Lab Scientists at Advanced Light Source Show Dislocations Can Be Induced by Pressure in Ultrafine Nanocrystals

Nanocrystals as protective coatings for advanced gas turbine and jet engines are receiving a lot of attention for their many advantageous mechanical properties, including their resistance to stress. However, contrary to computer simulations, the tiny size of nanocrystals apparently does not safeguard them from defects.

In a study by researchers with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab)and collaborators from multiple institutions, nanocrystals of nickel subjected to high pressure continued to suffer dislocation-mediated plastic deformation even when the crystals were only three nanometers in size. These experimental findings, which were carried out at Berkeley Lab’s Advanced Light Source (ALS), a premier source of X-rays and ultraviolet light for scientific research, show that dislocations can form in the finest of nanocrystals when stress is applied. (more…)

Read More

Space-Age Ceramics Get Their Toughest Test:

Berkeley Lab Researchers Develop Real-Time CT-Scan Test Rig For Ceramic Composites at Ultrahigh Temperatures

Advanced ceramic composites can withstand the ultrahigh operational temperatures projected for hypersonic jet and next generation gas turbine engines, but real-time analysis of the mechanical properties of these space-age materials at ultrahigh temperatures has been a challenge – until now. Researchers with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) have developed the first testing facility that enables CT-scanning of ceramic composites under controlled loads at ultrahigh temperatures and in real-time.

Working at Berkeley Lab’s Advanced Light Source (ALS), a premier source of X-ray and ultraviolet light beams, the scientists created a mechanical testing rig for performing X-ray computed microtomography that reveals the growth of microcrack damage under loads at temperatures up to 1,750 degrees Celsius. This allows engineers to compute a ceramic composite material’s risk of structural or mechanical failure under extreme operating conditions, which in turn should enable the material’s performance and safety to be improved. (more…)

Read More

Put a cork in it

Paper details use of natural material cork for quiet sandwich composites

Cork, known for its use in such low-tech applications as wine bottle stoppers and bulletin boards, now shows promise as the core material in composite sandwich structures for use in high-tech automotive, aircraft and energy applications.

A research team at the University of Delaware is investigating this natural material as an environmentally friendly solution for quiet sandwich composites. They recently published a paper on the work in Scientific Reports, an online, open-access research publication from the publishers of Nature that covers all areas of the natural sciences. (more…)

Read More

Self-Assembling Nanorods: Berkeley Lab Researchers Obtain 1, 2 and 3D Nanorod Arrays and Networks

A relatively fast, easy and inexpensive technique for inducing nanorods – rod-shaped semiconductor nanocrystals – to self-assemble into one-, two- and even three-dimensional macroscopic structures has been developed by a team of researchers with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab). This technique should enable more effective use of nanorods in solar cells, magnetic storage devices and sensors. It should also help boost the electrical and mechanical properties of nanorod-polymer composites.

Leading this project was Ting Xu, a polymer scientist who holds joint appointments with Berkeley Lab’s Materials Sciences Division and the University of California (UC) Berkeley’s Departments of Materials Sciences and Engineering, and Chemistry. Xu and her research group used block copolymers – long sequences or “blocks” of one type of monomer bound to blocks of another type of monomer – as a platform to guide the self-assembly of nanorods into complex structures and hierarchical patterns. Block copolymers have an innate ability to self-assemble into well-defined arrays of nano-sized structures over macroscopic distances. (more…)

Read More

UCLA Team Develops Highly Efficient Method for Creating Flexible, Transparent Electrodes

As the market for liquid crystal displays and other electronics continues to drive up the price of indium — the material used to make the indium tin oxide (ITO) transparent electrodes in these devices — scientists have been searching for a less costly and more dynamic alternative, particularly for use in future flexible electronics.

Besides its high price, ITO has several drawbacks. It’s brittle, making it impractical for use in flexible displays and solar cells, and there is a lack of availability of indium, which is found primarily in Asia. Further, the production of ITO films is relatively inefficient. (more…)

Read More

Imagine: Material That If Scratched, You Can Quickly and Easily Fix Yourself, With Light Not Heat

*Discovery of self-corrective healing process for polymer detailed this week in the journal Nature*

Imagine you’re driving your own new car–or a rental car–and you need to park in a commercial garage. Maybe you’re going to work, visiting a mall or attending an event at a sports stadium, and you’re in a rush. Limited and small available spots and concrete pillars make parking a challenge. And it happens that day: you slightly misjudge a corner and you can hear the squeal as you scratch the side of your car–small scratches, but large anticipated repair costs.

Now imagine that that you can repair these unsightly scratches yourself–quickly, easily and inexpensively–or that you can go through a car wash that can detect these and other more minor scratches and fix them as the car goes through the washing garage. Fantasy. Not exactly. Not anymore. Not according to a new discovery detailed in the April 21 issue of the journal Nature, and depicted in a short video interview and simulation. (more…)

Read More