Material Science News and Discussions

[weatheriscool]

Artificial intelligence for safer bike helmets and better shoe soles
https://techxplore.com/news/2023-12-art ... lmets.html
by ETH Zurich

Bike helmets that absorb the energy of an impact, running shoes that give you an extra boost with every step, or implants that behave just like natural bone. Metamaterials make such applications possible. Their inner structure is the result of a careful design process, following which 3D printers produce structures with optimized properties.

Researchers led by Dennis Kochmann, Professor of Mechanics and Materials in the Department of Mechanical and Process Engineering at ETH Zurich, have developed novel AI tools that bypass the time-consuming and intuition-based design process of metamaterials. Instead, they predict metamaterials with extraordinary properties in a rapid and automated fashion.

A novelty, their framework applies to large (so-called non-linear) loads, e.g., when a helmet absorbs major forces during an impact.

Kochmann's team has been among the pioneers in designing small-scale cellular structures (similar to beam networks in timber-frame houses) to create metamaterials with specific or extreme properties. "For example, we design metamaterials that behave like fluids: hard to compress but easy to deform. Or metamaterials that shrink in all directions when compressed in a particular one," explains Kochmann.

[weatheriscool]

Researchers find way to weld metal foam without melting its bubbles
https://techxplore.com/news/2023-12-wel ... -foam.html
by Matt Shipman, North Carolina State University

Researchers at North Carolina State University have now identified a welding technique that can be used to join composite metal foam (CMF) components together without impairing the properties that make CMF desirable. CMFs hold promise for a wide array of applications because the pockets of air they contain make them light, strong and effective at insulating against high temperatures.

CMFs are foams that consist of hollow, metallic spheres—made of materials such as stainless steel or titanium—embedded in a metallic matrix made of steel, titanium, aluminum or other metallic alloys. The resulting material is both lightweight and remarkably strong, with potential applications ranging from aircraft wings to vehicle armor and body armor.

In addition, CMF is better at insulating against high heat than conventional metals and alloys, such as steel. The combination of weight, strength and thermal insulation means that CMF also holds promise for use in storing and transporting nuclear material, hazardous materials, explosives and other heat-sensitive materials.

However, in order to realize many of these applications, manufacturers would need to weld multiple CMF components together. And that has posed a problem.

"Traditional fusion welding uses a filler to connect two pieces of metal," says Afsaneh Rabiei, professor of mechanical and aerospace engineering at NC State and corresponding author of a paper on the new research published in Advanced Engineering Materials titled "A Study on Welding of Porous Metals and Metallic Foams."

[weatheriscool]

Tantalum cold spray boosts potential of fusion reactor chambers
By Michael Franco
December 15, 2023
https://newatlas.com/physics/tantalum-b ... n-reactor/

The insides of nuclear fusion reactors are violent and chaotic places. A new cold-spray coating can take the heat and also trap some rogue hydrogen particles at the same time, potentially making for smaller, better plasma chambers.

While nuclear fusion is still in a very experimental stage, the powering up of the world's largest and most advanced tokamak fusion reactor in Japan this month shows that the technology is constantly moving from theory towards reality.

In fusion reactions, an ionized hydrogen gas known as plasma is subjected to levels of pressure and heat that equal those at the center of the Sun. This causes the atomic nuclei to fuse and release a tremendous amount of clean energy.

Creating the chambers that hold the plasma needed for fusion has been a challenge due to the extreme levels of heat and pressure they need to reach. Another issue with the process is that sometimes hydrogen atoms can get neutralized and escape from the plasma, which weakens its potency.

[weatheriscool]

Rubber that doesn't grow cracks when stretched many times
https://phys.org/news/2023-12-rubber-doesnt.html
by Leah Burrows, Harvard John A. Paulson School of Engineering and Applied Sciences

Researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have increased the fatigue threshold of particle-reinforced rubber, developing a new, multiscale approach that allows the material to bear high loads and resist crack growth over repeated use. This approach could not only increase the longevity of rubber products such as tires but also reduce the amount of pollution from rubber particles shed during use.

The research is published in Nature.

Naturally-occurring rubber latex is soft and stretchy. For a range of applications, including tires, hoses, and dampeners, rubbers are reinforced by rigid particles, such as carbon black and silica. Since their introduction, these particles greatly improve the stiffness of rubbers but not their resistance to crack growth when the material is cyclically stretched, a measurement known as the fatigue threshold.

[weatheriscool]

A novel sandwich-structured composite from biopolymers for building envelope applications
https://phys.org/news/2023-12-sandwich- ... tions.html
by Thamarasee Jeewandara , Phys.org

A new sandwich-structured composite has been developed from the surface layers of polyhydroxyalkanoate (PHA) and the interlayer of polylactic acid and cellulose microfibers. The biodegradable cellulose microfibers can be modified chemically with a sol-gel process to improve the compatibility between natural reinforcement and the polymer matrix.

While the modified cellulose microfibers were chemically developed through different processes to improve the compatibility of natural reinforcement at the polymer matrix, the modified cellulose microfibers showed highly hydrophobic characteristics with homogenous dispersion in the polylactic acid matrix.

Masoud Dadras Chomachayi and a research team at the Laval University, Canada, observed thermogravimetric analyses of the constructs to show improved thermal stability. They improved the mechanical properties of the constructs to increase its tensile modulus and strength. When the scientists added untreated fibers to the constructs, the water vapor permeability of the sandwich composite increased to show the superiority of modified cellulose microfibers when compared to untreated cellulose microfibers to develop building envelopes

.

[weatheriscool]

Swift 4-D printing with shape-memory polymers
https://phys.org/news/2023-12-swift-d-s ... ymers.html
by Thamarasee Jeewandara , Phys.org

Shape-memory polymers or shape-shifting materials are smart materials that have gained significant attention within materials science and biomedical engineering in recent years to build smart structures and devices. Digital light processing is a vat photopolymerization–based method with significantly faster technology to print a complete layer in a single step to create smart materials.

Fahad Alam and a team of scientists in electrical and computer engineering, and nuclear engineering at the King Abdullah University of Science and Technology, Saudi Arabia developed a facile and fast method to 3D print shape-memory polymer-based smart structures with a digital light printing 3D printer and custom resin.

They combined a liquid crystal (a material that can change its shape with temperature) with resin, to introduce shape-memory properties to directly 3D print thermoresponsive structures—while avoiding the complexity of resin preparation. The team printed the structures with different geometries and measured the shape-memory response. The shape-memory polymers can be conveniently prepared for use as smart tools, toys, and meta-materials.

[weatheriscool]

Piezo composites with carbon fibers for motion sensors
https://techxplore.com/news/2023-12-pie ... otion.html
by Tohoku University

An international research group has engineered a novel, high-strength flexible device by combining piezoelectric composites with unidirectional carbon fiber (UDCF), an anisotropic material that provides strength only in the direction of the fibers. The new device transforms kinetic energy from human motion into electricity, providing an efficient and reliable means for high-strength and self-powered sensors.

[weatheriscool]

Amorphous Silicon Carbide is Ten Times Stronger Than Kevlar and Great to Microchips
January 11, 2024 by Brian Wang

https://www.nextbigfuture.com/2024/01/a ... chips.html
Researchers at Delft University of Technology, led by assistant professor Richard Norte, have unveiled a remarkable new material with potential to impact the world of material science: amorphous silicon carbide (a-SiC). Beyond its exceptional strength, this material demonstrates mechanical properties crucial for vibration isolation on a microchip. Amorphous silicon carbide is therefore particularly suitable for making ultra-sensitive microchip sensors.

Amorphous silicon carbide boasts a yield strength 10 times greater than Kevlar, renowned for its use in bulletproof vests. IF you could make duct tape out of Amorphous silicon carbide you would need to hang about ten medium-sized cars end-to-end off that strip before it breaks.

The range of potential applications is vast. From ultra-sensitive microchip sensors and advanced solar cells, to pioneering space exploration and DNA sequencing technologies. The advantages of this material’s strength combined with its scalability make it exceptionally promising.

Nanostrings of Amorphous Silicon Carbide

The researchers adopted an innovative method to test this material’s tensile strength. Instead of traditional methods that might introduce inaccuracies from the way the material is anchored, they turned to microchip technology. By growing the films of amorphous silicon carbide on a silicon substrate and suspending them, they leveraged the geometry of the nanostrings to induce high tensile forces. By fabricating many such structures with increasing tensile forces, they meticulously observed the point of breakage. This microchip-based approach not only ensures unprecedented precision but also paves the way for future material testing.

[weatheriscool]

Tiny capsules that transform in the blink of an eye could be key to developing smaller electronics
https://phys.org/news/2024-01-tiny-caps ... aller.html
by Meg Cox, Loughborough University

Our phones and electronic devices could soon be smaller and sleeker without the risk of overheating thanks to microcapsules that transform in the blink of an eye.

Dr. Goran Vladisavljevic, of Loughborough University, and a team of researchers have designed and manufactured microcapsules filled with "phase change materials" (PCMs) that absorb heat by turning from a solid to a liquid when temperatures are elevated.

The paper, titled "Lego-Inspired Glass Capillary Microfluidic Device: A Technique for Bespoke Microencapsulation of Phase Change Materials," is published in ACS Applied Materials and Interfaces.

The capsules—which are around 0.2mm wide and do not require an energy source—could be used to absorb significant amounts of heat that would otherwise be transferred to elements in electronic devices.

[weatheriscool]

New superconducting material discovered in transition-metal dichalcogenides materials

by Zhao Weiwei and Zhang Changjin, Hefei Institutes of Physical Science, Chinese Academy of Sciences
https://phys.org/news/2024-01-supercond ... nides.html

With the support of electrical transport and magnetic measurement systems of Steady High Magnetic Field Facility (SHMFF), a research team from Hefei Institutes of Physical Science (HFIPS), Chinese Academy of Sciences (CAS), discovered a new superconducting material called (InSe2)xNbSe2, which possesses a unique lattice structure. The superconducting transition temperature of this material reaches 11.6 K, making it the transition metal sulfide superconductor with the highest transition temperature under ambient pressure.

The results were published in Journal of the American Chemical Society.

[weatheriscool]

Scientists spin naturalistic silk from artificial spider gland
https://phys.org/news/2024-01-scientist ... pider.html
by RIKEN

Researchers have succeeded in creating a device that spins artificial spider silk that closely matches what spiders naturally produce. The artificial silk gland was able to re-create the complex molecular structure of silk by mimicking the various chemical and physical changes that naturally occur in a spider's silk gland.

This eco-friendly innovation is a big step towards sustainability and could impact several industries. The study, led by Keiji Numata at the RIKEN Center for Sustainable Resource Science in Japan, along with colleagues from the RIKEN Pioneering Research Cluster, was published in the journal Nature Communications.

Famous for its strength, flexibility, and light weight, spider silk has a tensile strength that is comparable to steel of the same diameter, and a strength-to-weight ratio that is unparalleled. Added to that, it's biocompatible, meaning that it can be used in medical applications, as well as biodegradable. So why isn't everything made from spider silk? Large-scale harvesting of silk from spiders has proven impractical for several reasons, leaving it up to scientists to develop a way to produce it in the laboratory.

Spider silk is a biopolymer fiber made from large proteins with highly repetitive sequences, called spidroins. Within the silk fibers are molecular substructures called beta sheets, which must be aligned properly for the silk fibers to have their unique mechanical properties. Re-creating this complex molecular architecture has confounded scientists for years. Rather than trying to devise the process from scratch, RIKEN scientists took a biomimicry approach.

[weatheriscool]

Scientists announce breakthrough in hypersonic heat shield
https://techxplore.com/news/2024-01-sci ... hield.html
by Peter Grad , Tech Xplore

In a giant leap for future hypersonic flight, Chinese scientists have turned to multi-scale technology to develop a revolutionary new material that has achieved record high marks in tests for vital strength and thermal insulation properties.

The scientists say their porous ceramic creation opens the door to wider exploration in the fields of aerospace, chemical engineering and energy transfer and production.

"For the first time, it is reported a multi-scale structure design and fast fabrication of … high-entropy ceramics via an ultrafast high-temperature synthesis technique that can lead to exceptional mechanical load-bearing capability and high thermal insulation performance," the researchers said in a paper published Jan. 2 in the journal Advanced Materials.

Scientists have long faced challenges in developing strong, lightweight materials boasting low-thermal conductivity that are critical, especially for hypersonic travel. Ceramic materials offer promise because they exhibit low thermal conductivity, high melting points and corrosion resistance, and they are also non-combustible.

[weatheriscool]

Airborne infection risk plummets in face of metal nanoparticle spray
By Michael Franco
January 25, 2024
https://newatlas.com/materials/airborne ... cle-spray/

As recent history proves, airborne respiratory infections are not to be trifled with. Now, a new sprayable coating applied to standard air filters might give us a leg up in the war against the pathogens that cause these diseases.

Measles. Influenza. SARS. MERS. Pneumonia. Think of a major infectious disease, and the chances are that it is spread by airborne pathogens. Currently, COVID-19 and TB are the world's deadliest infectious diseases, and both are transmitted through the air. So when it comes to tamping down the risk of disease spreading through populations, developing solutions that can knock infectious bugs out of the air is paramount.

[weatheriscool]

Graphene replaces sand to make lighter, stronger concrete
By Michael Irving
January 28, 2024

https://phys.org/news/2024-01-sea-metha ... lands.html
When you think of resources we’re running out of, sand might not be high on your list, but it’s up there thanks to our high demand for concrete. Scientists at Rice University have now shown that substituting graphene can not only save sand, but makes concrete lighter, stronger and tougher.

Despite being a sheet of carbon atoms just one atom thick, graphene has a reputation for being incredibly strong. As such, it’s no surprise that this 'wonder material' has been mixed into concrete before, usually to make it stronger and more durable. But that usually involves just adding graphene to the recipe – for the new study, the Rice team wanted to replace sand completely.

Concrete is made of three main ingredients: water, an aggregate like sand, and cement to bind it all together. Sand is the largest component by volume, and given modern humanity’s insatiable appetite for concrete, sand mining is increasing. Not only is this process destructive, but it risks running out of sources.

The research comes from the lab of Rice University chemist James Tour, whose team has been making graphene for years using a technique they developed called flash Joule heating. Essentially, a carbon-rich base material is quickly superheated with a zap of electricity, converting it into graphene flakes. In this case, the base material was metallurgical coke, a fuel source created from coal.

[weatheriscool]

A type of plastic that can be shape-shifted using tempering
https://phys.org/news/2024-02-plastic-s ... ering.html
by Bob Yirka , Phys.org

A team of molecular engineers have developed a type of plastic that can be shape-shifted using tempering. In their paper published in the journal Science the team, from the University of Chicago, with a colleagues from the US DEVCOM Army Research Laboratory, Aberdeen Proving Ground, the National Institutes of Standards and Technology and the NASA Glenn Research Center, describe how they made their plastic and how well it was able to shape shift when they applied various types of tempering.

[weatheriscool]

Researchers create green steel from toxic red mud in 10 minutes
By Paul McClure
February 06, 2024

Researchers have devised an economically viable way of reducing the environmental impact of both the steel and aluminum industries by using hydrogen to melt down the toxic red mud left over from aluminum production to produce green steel in around 10 minutes.

The aluminum industry produces around 198 million tons (180 million tonnes) of bauxite residue – ‘red mud’ – yearly, which is extremely corrosive because it has high alkalinity and is rich in toxic heavy metals. In countries such as Australia, China and Brazil, the leftover red mud is usually disposed of in gigantic landfills, with high processing costs. The steel industry is equally environmentally damaging, responsible for 8% of global carbon dioxide emissions. Yet, the demand for steel and aluminum is forecast to increase by up to 60% by 2050.

https://newatlas.com/materials/toxic-ba ... een-steel/

[weatheriscool]

Surprise physics in insulating material offer path for faster tech
https://phys.org/news/2024-02-physics-i ... aster.html
by Syl Kacapyr, Cornell University

Researchers led by Cornell have discovered an unusual phenomenon in a metal-insulating material, providing valuable insights for the design of materials with new properties by way of faster switching between states of matter.

Mott insulators are a family of materials with unique electronic properties, including ones that can be manipulated by stimuli such as light. The origin of the unique properties is not fully understood, partly due to the challenging task of imaging the material's nanostructures in real-space and capturing how these structures undergo phase changes in as fast as a trillionth of a second.

[weatheriscool]

BREKTHROUGH : Non-Fading Structural Color For Airplane Paint With 10% of the Weight
February 10, 2024 by Brian Wang

A new way of creating color uses the scattering of light of specific wavelengths around tiny, almost perfectly round silicon crystals. This Kobe University development enables non-fading structural colors that do not depend on the viewing angle and can be printed. The material has a low environmental and biological impact and can be applied extremely thinly, promising significant weight improvements over conventional paints.

Above -The nanospheres in a methanol suspension have different colors than when applied to a surface as a monolayer. The Kobe University researchers explain, “This is due to the multiple scattering, i.e., blue light subsides during consecutive scattering by absorption, while red light survives.” © FUJII Minoru (CC BY)

https://www.nextbigfuture.com/2024/02/b ... eight.html

[weatheriscool]

Polymer-based tunable optical components allow for metasurfaces that can switched with light
https://phys.org/news/2024-02-polymer-b ... nents.html
by Marco Körner, Friedrich Schiller University of Jena

A material coating, whose light refraction properties can be precisely switched between different states, has been developed by an interdisciplinary research team from the Chemistry and Physics departments at the University of Jena. The team, led by Felix Schacher, Sarah Walden, Purushottam Poudel, and Isabelle Staude, combined polymers that react to light with so-called metasurfaces.

This innovation has led to the creation of new optical components that could potentially be used in signal processing. Their findings have now been published in the journal ACS Nano.

[weatheriscool]

3D-printed titanium lattice is 50% stronger than WE54 aerospace alloy
By Loz Blain
February 26, 2024
https://newatlas.com/materials/3d-print ... tice-rmit/

A new type of 3D-printed lattice structure has surprised researchers with its strength and light weight. It uses two different lattice structures merged together to eliminate the weak points normally found in these complex shapes.

RMIT researchers in Melbourne, Australia, took hollow-strut lattice designs as a starting point, inspired by hollow-stemmed water lilies and organ pipe coral, and then looked at ways to reduce the high stress concentrations created at the join points.

“Ideally, the stress in all complex cellular materials should be evenly spread,” said Distinguished Professor Ma Qian, lead author on a new study. “However, for most topologies, it is common for less than half of the material to mainly bear the compressive load, while the larger volume of material is structurally insignificant.”

The researchers reinforced the tubular lattice by overlaying a second lattice over the top, adding a thin X-shaped cross-section running through the tubes and joints that distributes load much more evenly in compression testing.