Just as a delicate balance of ingredients determines the tastiness of a cookie or cake, the specific ratio of metals in an alloy determines desirable qualities of the new metal, such as improved strength or lightness. A new class of alloys, called high entropy alloys, is unique in that these alloys contain five or more elements mixed evenly in near equal concentrations and have shown exceptional engineering properties.
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In a new paper, a team of Yale Univ. researchers assesses the “criticality” of all 62 metals on...
As you heat up a piece of iron, the arrangement of the iron atoms changes several times before melting. This unusual behavior is one reason why steel, in which iron plays a starring role, is so sturdy and ubiquitous in everything from teapots to skyscrapers. But the details of just how and why iron takes on so many different forms have remained a mystery.
Researchers have demonstrated a technique for mapping deformation in metals that can recover destroyed serial numbers on metal objects such as firearms, a common challenge in forensics. The technique might also meet other forensic needs such as reconstructing vehicle identification numbers or imprints on ammunition casings.
When a metal tube lines an oil well thousands of feet below the surface of the ocean, that metal had better be solid and reliable. Unfortunately, the environment in such deep wells is often rich in hydrogen, a gas that can penetrate high-tech alloys and make them brittle, making fractures and leaks more likely. Now researchers have figured which characteristics of a metal structure foster this embrittlement in the presence of hydrogen.
Earth’s magnetic field is crucial for our existence, as it shields the life on our planet’s surface from deadly cosmic rays. It is generated by turbulent motions of liquid iron in Earth’s core. Iron is a metal, which means it can easily conduct a flow of electrons that makes up an electric current. New findings show a missing piece of the traditional theory explaining why metals become less conductive when they are heated.
Rust never sleeps. Whether a reference to the 1979 Neil Young album or a product designed to protect metal surfaces, the phrase invokes the idea that corrosion from oxidation is an inevitable, persistent process. But a new Binghamton Univ. study reveals that certain features of metal surfaces can stop the process of oxidation in its tracks.
Researchers have developed a new “high-entropy” metal alloy that has a higher strength-to-weight ratio than any other existing metal material. High-entropy alloys are materials that consist of five or more metals in approximately equal amounts.
Nanoporous metals have a wide range of applications because of their superior qualities. They posses a high surface area for better electron transfer, which can lead to the improved performance of an electrode in an electric double capacitor or battery. Nanoporous metals offer an increased number of available sites for the adsorption of analytes, a highly desirable feature for sensors.
Yale Univ. engineer Jan Schroers will lead a three-year, $1.2 million project intended to dramatically accelerate the pace of discovering and characterizing bulk metallic glasses (BMGs), a versatile type of pliable glass that’s stronger than steel. The grant will enable Schroers’ team to screen more than 3,000 potential BMG alloys in a week, a vast improvement over traditional methods.
Research at Oak Ridge National Laboratory has cracked one mystery of glass to shed light on the mechanism that triggers its deformation before shattering. The study improves understanding of glassy deformation and may accelerate broader application of metallic glass, a moldable, wear-resistant, magnetically exploitable material that is thrice as strong as the mightiest steel and ten times as springy.
Univ. of Texas at Arlington engineering professors have received an Air Force grant to examine the material surface at the micro- and nano-scale level that will provide clues for predicting fatigue in aircraft parts. The new approach will rely on a scanning whitelight interferometric surface profiler integrated with a compact mechanical tester and an electron backscatter diffraction module to deliver in-situ 3-D surface profiling.
The phase-out of traditional incandescent bulbs in the U.S. and elsewhere, as well as a growing interest in energy efficiency, has given LED lighting a sales boost. That trend could be short-lived as key materials known as rare earth elements become more expensive. Scientists at Rutgers Univ., however, have now designed new materials for making household LED bulbs without using these ingredients.
Iron catalysts remove oxygen inexpensively, but are susceptible to rust or oxidation in biofuel production. Precious metals that resist corrosion are even less efficient at removing oxygen. But adding just a touch of palladium to the iron produces a catalyst that quickly removes oxygen atoms, easily releases the desired products, and doesn't rust, according to scientists at Pacific Northwest National Laboratory and Washington State Univ.
Swedish and Chinese researchers have recently shown how a unique nano-alloy composed of palladium nano-islands embedded in tungsten nanoparticles creates a new type of catalysts for highly efficient oxygen reduction, the most important reaction in hydrogen fuel cells. Their results are published in the scientific journal Nature Communications.
The key to creating a material that would be ideal for converting solar energy to heat is tuning the material’s spectrum of absorption just right: It should absorb virtually all wavelengths of light that reach Earth’s surface from the sun—but not much of the rest of the spectrum, since that would increase the energy that is reradiated by the material, and thus lost to the conversion process.
Researchers are developing a robotic fabric that moves and contracts and is embedded with sensors, an approach that could lead to "active clothing" or a new class of "soft" robots. The robotic fabric, developed at Purdue Univ., is a cotton material containing sensors made of a flexible polymer and threadlike strands of a shape-memory alloy that return to a coiled shape when heated, causing the fabric to move.
Donald Sadoway and his colleagues at the Massachusetts Institute of Technology have already started a company to produce electrical-grid-scale liquid batteries, whose layers of molten material automatically separate due to their differing densities. But a newly developed formula substitutes different metals for the molten layers. The new formula allows the battery to work at a much lower temperature.
Researchers from North Carolina State Univ. have developed a technique for controlling the surface tension of liquid metals by applying very low voltages, opening the door to a new generation of reconfigurable electronic circuits, antennas and other technologies. The technique hinges on the fact that the oxide “skin” of the metal acts as a surfactant, lowering the surface tension between the metal and the surrounding fluid.
Researchers have been trying to increase the efficiency of solid oxide fuel cells by lowering the temperatures at which they run. In a serendipitous finding at Pacific Northwest National Laboratory, researchers have created a new form of strontium-chromium oxide that performs as a semiconductor and also allows oxygen to diffuse easily, a requirement for a solid oxide fuel cell.
When it comes to diesel engine catalysts, which are responsible for cleansing exhaust fumes, platinum has unfortunately proved to be the only viable option. This has resulted in material costs alone accounting for half of the price of a diesel catalyst. Researchers in Denmark say they have developed a new way to manufacture catalysts that may result in a 25% reduction in the use of platinum.
A new concept in metallic alloy design has yielded a multiple-element material that not only tests out as one of the toughest on record, but, unlike most materials, the toughness as well as the strength and ductility of this alloy actually improves at cryogenic temperatures. This multi-element alloy was synthesized and tested through a collaboration of researchers.
A new concept in metallic alloy design called “high-entropy alloys” has yielded a multiple-element material that tests out as one of the toughest on record. But, unlike most materials, the toughness as well as the strength and ductility of this alloy, which contains five major elements, actually improves at cryogenic temperatures.
When metallic lithium forms and deposits during the charging process in a lithium-ion battery, it can lead to a reduced battery lifespan and even short circuits. Using neutron beams, scientists have now peered into the inner workings of a functioning battery without destroying it. In the process, they have resolved this so-called lithium plating mystery.
The field of astrophysics has a stubborn problem and it’s called lithium. The quantities of lithium predicted to have resulted from the Big Bang are not actually present in stars. But the calculations are correct, a fact which has now been confirmed for the first time in experiments conducted at the underground laboratory in the Gran Sasso mountain in Italy.
Sensors made with copper could be cheap, light, flexible and highly conductive. Making such concepts affordable enough for general use remains a challenge but a new way of working with copper nanowires and a PVA “nano glue” could be a game-changer. Engineers in Australia have found a way of making flexible copper conductors cost-effective enough for commercial applications.
For tiny fractions of a second, when illuminated by a laser pulse, quartz glass can take on metallic properties. The phenomenon, recently revealed by large-scale computer simulations, frees electrons, allowing quartz to become opaque and conduct electricity. The effect could be used to build logical switches which are much faster than today’s microelectronics.
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