Silver-Diamond Composite Offers Unique Capabilities for Cooling Powerful Defence Microelectronic
Researchers at the Georgia Tech Research Institute (GTRI) are developing a solid composite material to help cool small, powerful microelectronics used in defence systems. The material, composed of silver and diamond, promises an exceptional degree of thermal conductivity compared to materials currently used for this application. The research is focused on producing a silver-diamond thermal shim of unprecedented thinness - 250 microns or less. The ratio of silver to diamond in the material can be tailored to allow the shim to be bonded with low thermal-expansion stress to the high-power wide-bandgap semiconductors planned for next generation phased array radars. Read more
Caltech-Led Team Creates Damage-Tolerant Metallic Glass
Amorphous palladium-based alloy demonstrates unprecedented level of combined toughness and strength; could be of use in biomedical implants
Glass is inherently strong, but when it cracks or otherwise fails, it proves brittle, shattering almost immediately. Steel and other metal alloys tend to be tough - they resist shattering - but are also relatively weak; they permanently deform and fail easily.
The ideal material, says Marios Demetriou, a senior research fellow at the California Institute of Technology (Caltech), has the advantage of being both strong and tough - a combination called damage tolerance, which is more difficult to come by than the layperson might think.
A metal alloy masquerading as a glass is the first material to be fabricated that is as strong and as tough as the toughest steel. The feat could eventually see such materials replace steel in buildings, cars or bridges. The terms 'strength' and 'toughness' may be used almost interchangeably in everyday life, but until now, no materials have been found that display both these characteristics. Some materials, such as glass, are strong - that is, they are scratch-resistant and it is difficult to permanently bend them out of shape when you place a heavy load on them - but they also tend to be brittle. Others, such as metal, are tough - that is, they are more difficult to shatter - but they are generally more malleable. Read more
String theory, which some physicists hope may be able to unify gravity and quantum mechanics, may have found a real-world application. A type of black hole predicted by string theory may help to explain the properties of a mysterious class of materials called 'strange metals'. The electrical resistance of strange metals increases linearly with temperature rather than with the square of the temperature as in normal metals. They also have other excitations of energy that can be thought of as especially short-lived particles. Read more
A liquid armour has been shown to stop bullets in tests carried out by UK scientists at BAE systems in Bristol. The researchers have combined this "shear-thickening" liquid with Kevlar to create a new bullet-proof material. The company is keeping the chemical formula of the liquid a secret, but it works by absorbing the force of the bullet strike and responding to it by becoming much thicker and more sticky. Read more
Lotus Plant-Inspired Dust-Busting Shield to Protect Space Gear Researchers at NASA's Goddard Space Flight Centre in Greenbelt, Md., are developing a transparent coating that prevents dirt from sticking in the same way a lotus plant sheds water - work begun through collaboration with Northrop Grumman Electronics Systems, Linthicum, Md., and nGimat Corporation, Atlanta, Ga. Although a lotus leaf appears smooth, under a microscope, its surface contains innumerable tiny spikes that greatly reduce the area on which water and dirt can attach.
In nature, trees pull vast amounts of water from their roots up to their leaves hundreds of feet above the ground through capillary action, but now scientists at the University of Rochester have created a simple slab of metal that lifts liquid using the same principlebut does so at a speed that would make nature envious. The metal, revealed in an upcoming issue of Applied Physics Letters, may prove invaluable in pumping microscopic amounts of liquid around a medical diagnostic chip, cooling a computer's processor, or turning almost any simple metal into an anti-bacterial surface.
"We're able to change the surface structure of almost any piece of metal so that we can control how liquid responds to it. We can even control the direction in which the liquid flows, or whether liquid flows at all" - Chunlei Guo, associate professor of optics at the University of Rochester.
Scientists from the UK Ministry of Defence (MoD) have devised an ultra-hard vehicle armour to protect military personnel. Details of the steel armour, called Super Bainite, were outlined during a seminar at the University of Cambridge. Unexpectedly, the MoD team has given the armour a protective advantage by introducing an array of holes. According to scientist Professor Peter Brown, these perforations help deflect incoming projectiles.
Scientists Create Tough Ceramic That Mimics Mother of Pearl Biomimicry technological innovation inspired by nature is one of the hottest ideas in science but has yet to yield many practical advances. Time for a change. Scientists with the U.S. Department of Energys Lawrence Berkeley National Laboratory (Berkeley Lab) have mimicked the structure of mother of pearl to create what may well be the toughest ceramic ever produced. Through the controlled freezing of suspensions in water of an aluminium oxide (alumina) and the addition of a well known polymer, polymethylmethacrylate (PMMA), a team of researchers has produced ceramics that are 300 times tougher than their constituent components. The team was led by Robert Ritchie, who holds joint appointments with Berkeley Labs Materials Sciences Division and the Materials Science and Engineering Department at the University of California, Berkeley.
Some of the strongest, most durable and heat resistant materials on earth are to be developed in the UK, thanks to a new £6 million centre for structural ceramics announced today. The Imperial College Structural Ceramic Centre (ICSCC), funded over a 5-year period by an Engineering and Physical Sciences Research Council (EPSRC) Science and Innovation Award, is a joint project between Imperial College London's Departments of Materials and Mechanical Engineering. The new centre aims to dramatically improve the strength and durability of structural ceramics, made of inorganic materials like oxides, carbides and nitrides, to meet industrial demand for materials that can withstand extreme environments.