Shuffling the load

Scientists use neutrons to discover strengthening behavior in alloys

Oak Ridge National Laboratory researchers have identified a mechanism in a 3D-printed alloy – termed “load shuffling” — that could enable the design of better-performing lightweight materials for vehicles.

One way to improve energy efficiency in vehicles is to make them lighter with aluminum-based materials. Researchers monitored a version of ORNL’s ACMZ — aluminum, copper, manganese and zirconium — alloy for deformation that occurs when the material is under persistent mechanical stress at high temperatures.

Using neutron diffraction, researchers studied the material’s atomic structure and observed that the overall stress was absorbed by one part of the alloy but transferred to another part during deformation. This back-and-forth shuffling prevents strengthening in some areas.

“Neutrons offer opportunities to study metallurgical phenomena in multi-phase structural materials,” ORNL’s Amit Shyam said. “We’ve gained unprecedented insight into elevated-temperature material behavior that will allow us to design improved aluminum alloys for extreme conditions.”


A reveille for more biomass

Agave gene delays poplar dormancy with big results

A team of scientists led by Oak Ridge National Laboratory discovered the gene in agave that governs when the plant goes dormant and used it to create poplar trees that nearly doubled in size, increasing biomass yield for biofuels production and carbon sequestration.

By sequencing the messenger RNA of Agave americana, researchers found the REVEILLE1 gene that controls both dormancy and budding. A study showed that poplar engineered with the gene could potentially extend their growing season by two to three months in temperate regions.

Poplar with REVEILLE1 achieved a 166% increase in biomass when grown in a greenhouse, yielding taller trees with larger leaves and thicker stems compared with standard poplars.

“Much like the circadian clock responds to light and dark, REVEILLE genes regulate when plants are asleep in dormancy and when they’re awake,” said ORNL’s Xiaohan Yang. “We used the gene to successfully repress dormancy over two winters.”  — Stephanie Seay


Designer molecules may help valuable minerals float

Insights on rare-earth mineral monazite shape critical material recovery

Critical Materials Institute researchers at Oak Ridge National Laboratory and Arizona State University studied monazite mineral, an important source of rare-earth elements, to enhance methods of recovering critical materials for energy, defense and manufacturing applications.

Rare-earth elements occur together naturally in mineral ores such as monazite but are economically challenging to recover. New approaches to separate the valuable ore from unwanted materials are needed.

The research team combined theory and experiment to gain atom-level insights on monazite, providing a first look at surface features important to the design of flotation collector molecules – materials that work like life jackets to buoy up monazite particles on air bubbles from mixed mineral slurries.

“Our efforts address materials needed for froth flotation techniques used to separate high-grade ore from low-value materials during processing. Fundamental research can help us tailor future collectors to make monazite recovery more efficient and cost-effective,” said ORNL’s Vyacheslav Bryantsev.


‘T’ molecules huddle around rare earth elements

Atomic-scale details observed during liquid-liquid extraction

Researchers at Oak Ridge National Laboratory zoomed in on molecules designed to recover critical materials via liquid-liquid extraction, or LLE — a method used by industry to separate chemically similar elements.

The team previously designed a novel ligand, or collector molecule, to grab select lanthanides from rare-earth mineral solutions.

Lanthanides are rare-earth metals critical to energy and national security technologies for magnets, electronics and catalysts. They occur together naturally in mineral ore deposits, but their chemical similarities make separating individual elements difficult. LLE methods leverage self-separating liquids such as oil and water to isolate a target material. One example is dividing light and heavy lanthanides. The new study describes how the process unfolds, finding that an unexpected T-shaped cluster forms around target metals, acting like a magnet to create larger aggregates.

“These atomic-scale details are difficult to observe and could help us improve future rare-earth separation strategies,” said ORNL’s Alex Ivanov.