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A simple alloy has claimed the crown for toughest material ever recorded. In a new study, a team led by researchers at Berkeley Lab ran the alloy through a series of tests and discovered not only its incredible toughness, but high strength and ductility that actually improve in colder temperatures, unlike most known materials.

The alloy in question contains chromium, cobalt and nickel (CrCoNi), and it belongs to a class of metals called high entropy alloys (HEAs). Most alloys are made up of one dominant element with smaller amounts of others added in, but HEAs contain equal amounts of each element. This can give them some impressive properties, such as high strength-to-weight ratios, an elastic modulus that rises with the temperature, or ultra strength and ductility.

In previous work, the researchers found that CrCoNi showed high strength and toughness at low temperatures of around −196 °C (−321 °F). For the new study, the team investigated how it would hold up at even colder temperatures of −253 °C (−424 °F), at which helium exists as a liquid. And sure enough, its toughness hit new heights in preventing cracks propagating.

A textbook theory for the freezing of water also explains the growth of a new phase in a more complicated phase transition of a different material.

When water freezes, the ice forms first in “nuclei”—tiny seed crystals that can grow or shrink and survive only if they reach a minimum size—at least according to the textbook theory. Researchers have now shown that this understanding also applies to a more complicated phase transition in vanadium dioxide (VO₂), a material whose electrical properties and crystal structure both change at its so-called metal-to-insulator phase transition [1]. The team measured the threshold size for the “seeds” that drive this transition and demonstrated a new technique for studying crystal structure transitions. The result suggests that the classical nucleation theory is valid for a range of materials that are important in areas such as catalysis, lasers, and alloy and ceramic manufacturing.

Place a bucket of purified water in a subfreezing-temperature environment, and tiny ice seeds will start forming. Many will quickly dissolve, but those that are larger than a certain threshold size will grow and eventually merge to make a single block of ice. This view of crystallization, associated with classical nucleation theory, has been well accepted for the water–ice transition. Junqiao Wu of the University of California, Berkeley, and his colleagues wanted to test whether the same nucleation phenomenon is at play in VO₂ when it makes a transition from one crystalline structure to another.

The asteroid strike simulation website lets users customize material, size, and speed then witness the destruction, in the name of science.

Intel released nine research papers at IEDM 2022 that lay the groundwork for future chip designs as the company looks to deliver on its promise of developing processors with over a trillion transistors by 2030.

The research includes new 2D materials for transistors, new 3D packaging technology that narrows the performance and power gap between chiplet and single-die processors to a nearly-imperceptible range, transistors that ‘don’t forget’ when power is removed, and embedded memories that can be stacked directly on top of transistors and store more than one bit per cell, among other innovations.

It was a simple idea—maybe even too simple to work.

Research scientist James Ponder and a team of Georgia Tech chemists and engineers thought they could design a transparent polymer film that would conduct electricity as effectively as other commonly used materials, while also being flexible and easy to use at an industrial scale.

They’d do it by simply removing the nonconductive material from their conductive element. Sounds logical, right?

😁

Using well-known materials and manufacturing processes, researchers have built an effective, passive, ultrathin laser isolator that opens new research avenues in photonics.

Year 2017 😗

In 2015, researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) developed the first on-chip metamaterial with a refractive index of zero, meaning that the phase of light could be stretched infinitely long. The metamaterial represented a new method to manipulate light and was an important step forward for integrated photonic circuits, which use light rather than electrons to perform a wide variety of functions.

Now, SEAS researchers have pushed that technology further — developing a zero-index waveguide compatible with current silicon photonic technologies. In doing so, the team observed a physical phenomenon that is usually unobservable—a standing wave of light.

Continue reading “A zero-index waveguide: Researchers directly observe infinitely long wavelengths for the first time” »

An adaptable new device can transform into all the key electric components needed for artificial-intelligence hardware, for potential use in robotics and autonomous systems, a new study finds.

Brain-inspired or “neuromorphic” computer hardware aims to mimic the human brain’s exceptional ability to adaptively learn from experience and rapidly process information in an extraordinarily energy-efficient manner. These features of the brain are due in large part to its plastic nature —its ability to evolve its structure and function over time through activity such as neuron formation or “neurogenesis.”

“We hypothesized if we could mimic these neurogenesis behaviors in electrical hardware, we could make machines that learn throughout their life-spans,” says study senior author Shriram Ramanathan, an electrical engineer and materials scientist at Purdue University, in West Lafayette, Ind.

A team in Korea has used sound waves to connect tiny droplets of liquid metals inside a polymer casing. The novel technique is a way to make tough, highly conductive circuits that can be flexed and stretched to five times their original size.

Making stretchable electronics for skin-based sensors and implantable medical devices requires materials that can conduct electricity like metals but deform like rubber. Conventional metals don’t cut it for this use. To make elastic conductors, researchers have looked at conductive polymers and composites of metals and polymers. But these materials lose their conductivity after being stretched and released a few times.

Liquid metals, alloys that stay liquid at room temperature, are a more promising option. Gallium-based liquid metals, typically alloys of gallium and indium, have caught the most attention because of their low toxicity and high electrical and heat conductivity. They are also tough because of an oxide skin that forms on their surface, and they stick well to various substrates.