Lifeboat Foundation: Safeguarding Humanity
Toggle light / dark theme

Blog

Category: materials – Page 49

Rare crystal shape found to increase the strength of 3D-printed metal

Andrew Iams saw something strange while looking through his electron microscope. He was examining a sliver of a new aluminum alloy at the atomic scale, searching for the key to its strength, when he noticed that the atoms were arranged in an extremely unusual pattern.

“That’s when I started to get excited,” said Iams, a materials research engineer, “because I thought I might be looking at a .”

Not only did he find quasicrystals in this , but he and his colleagues at the National Institute of Standards and Technology (NIST) found that these quasicrystals also make it stronger. They have published their findings in the Journal of Alloys and Compounds.

Stainless steel strengthened: Twisting technique creates submicron ‘anti-crash wall’

A combined team of metallurgists, materials scientists and engineers from the Chinese Academy of Sciences, Shandong University and the Georgia Institute of Technology has developed a way to make stainless steel more resistant to metal fatigue. In their study published in the journal Science, the group developed a new twisting technique that functions as an “anti-crash wall” in the steel, giving it much more strength and resistance to cyclic creep.

Metal can experience when bent many times, leading to breaking. When this occurs in critical applications, it can result in catastrophic accidents such as bridge failures. Because of that, scientists have for many years been working to reduce or prevent stress levels in metals. In this new effort, the researchers found a way to dramatically improve the strength of a type of stainless steel while also boosting its resistance to what is known as cycle creep, where fatigue occurs due to ratcheting, a form of repeated bending.

The new technique involved repeatedly twisting a sample of 304 austenitic stainless steel in a machine in certain ways. This led to spatially grading the cells that made up the metal, resulting in the build-up of what the team describes as a submicron-scale, three-dimensional, anti-crash wall. Under a microscope, the researchers found an ultra-fine, sub-10 nanometer, coherent lamellar structure that slowed dislocation by preventing stacking faults.

A new frontier in spintronics: Antiferromagnetic quasicrystals unveiled

Quasicrystals (QCs) are fascinating solid materials that exhibit an intriguing atomic arrangement. Unlike regular crystals, in which atomic arrangements have an ordered repeating pattern, QCs display long-range atomic order that is not periodic. Due to this ‘quasiperiodic’ nature, QCs have unconventional symmetries that are absent in conventional crystals.

Since their Nobel Prize-winning discovery, condensed matter physics researchers have dedicated immense attention toward QCs, attempting to both realize their unique quasiperiodic magnetic order and their possible applications in spintronics and .

Ferromagnetism was recently discovered in the gold-gallium-rare earth (Au-Ga-R) icosahedral QCs (iQCs). Yet scientists were not surprised by this observation because translational periodicity—the repeating arrangement of atoms in a crystal—is not a prerequisite for the emergence of ferromagnetic order.

Molecules in a Twist: How a Flash of Light Flips Chirality

Scientists in Japan have uncovered a surprising twist, literally, in how molecules organize themselves. By introducing tiny leftover fragments from previous assemblies, they discovered a way to flip the direction of helical molecular structures.

Using specific intensities of UV and visible light, they controlled whether these molecules formed left-handed or right-handed spirals, revealing a new method to fine-tune optical and electronic properties. This groundbreaking insight could unlock novel ways to engineer smarter, more responsive materials.

Revealing the power of molecular self-assembly.

Transparent paper-based material can hold boiling water and degrade in deep ocean in under a year

A team of biomaterial engineers, environmental resource specialists and industrial design researchers affiliated with a host of institutions across Japan has developed a biodegradable material that is clear and can hold boiling water—and it degrades in less than a year after settling on the ocean floor. Their work is published in the journal Science Advances.

Prior research has shown that millions of tons of plastics are piling up in the environment, including on the . Because of this, scientists have been looking for better, biodegradable replacements. In this new effort, the research team has developed a paper-based, clear, that can stand up to liquids for several hours, even those that have been heated, allowing them to replace plastic cups, straws, and other everyday objects.

The research team made the material by starting with a standard cellulose hydrogel. After drying, the material was treated with an aqueous lithium bromide solution which forced the cellulose to solidify into desired shapes. The researchers note that end-products could be as thin as plastic cup walls, or as thick as desired. They describe the material as tPB, a transparent 3D material made solely of cellulose.

Titanium microparticles prevalent in oral tissue around dental implants, study shows

Titanium micro-particles in the oral mucosa around dental implants are common. This is shown in a new study from the University of Gothenburg and Uppsala University, which also identified 14 genes that may be affected by these particles.

Registry data indicate that about 5% of all adults in Sweden have —and potentially also titanium particles in the tissue surrounding the implants. According to the researchers, there is no reason for concern, but more knowledge is needed.

“Titanium is a well-studied material that has been used for decades. It is biocompatible and safe, but our findings show that we need to better understand what happens to the micro-particles over time. Do they remain in the tissue or spread elsewhere in the body?” says Tord Berglundh, senior professor of periodontology at Sahlgrenska Academy, University of Gothenburg.

/* */