source：Ames Tribune
The future of cheaper, cleaner, more precise and energy-efficient refrigeration, the seamless shapeshifting of elemental metals and the geopolitics of rare earth metals were all on display during Assistant Secretary for the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy (EERE) Daniel Simmons’ tour of the Ames Laboratory on Tuesday.
“Ames has some of the most important critical materials, and has been working on them for the past 70 years,” Simmons said. “One of the things that’s been helpful about visiting Ames is seeing the work they do on materials to renew energy.”
At the Ames Lab, a U.S. Department of Energy research facility operated by Iowa State University, Simmons, along with EERE representatives toured three separate Ames Lab facilities and participated in a manufacturing roundtable discussion with representatives from Ames Lab, ISU, Alliant Energy and the governor’s office.
Simmons oversees technology development in the energy efficiency, renewable power and sustainable transportation sectors and identified rare earth metals, groups of similar metallic elements that are essential parts of many high-tech devices, as a pressing issue in geopolitics.
As the United States seeks to build a dependence on rare earth metals in the future, top competitor China leads the nation in top rare-earth mineral mining reserves, producing an estimated 44 million tons, to the United States’ 1.4 tons.
Inside the Metal Preparation Center, a specialized research center in the Ames Lab, non-commercial rare earth metals such as Scandium (alloys for aerospace and sports equipment) and Thulium (used in banknotes) are graded, refined and provided by the lab to clients for various purposes.
“In addition to the rare earths being high-quality, we also have our calcium being sold at high-quality as well,” said Matt Besser, a scientist at the Materials Preparation Center.
The work of scientists Iver Anderson and Emma White can best be shown through an hourglass.
Instead of grains of sand or salt, Simmons viewed various metal powders, ranging in smoothness and thickness through the lens of an hourglass.
Some needed to be roughly shaken to flow through the glass, others fluidly swam in the encasing with a simple flip — but regardless, Anderson and White have turned the science of powder atomization into an art form.
Techniques for atomization include metal that is forced through an orifice at a high velocity to ensure turbulent flow from metal to liquid in mere milliseconds. Once the liquid droplets form, they solidify rapidly as they fall through a spray chamber and are cooled by additional gas halos — thus turning the substance into powder.
“If you think about it like a recipe, there are ingredients and combinations in a recipe that will make something totally new,” Anderson said to the Tribune. “We can actually make them amorphous, glass-like, so they have all these unexpected properties that can produce unexpected results.”
The benefits of powder atomization include a increased design flexibility and improved machinability, and the team is working toward alloy development for powder feedstock material for additive manufacturing, known as 3D printing.
“It’s not just the alloy composition itself and the mixture of elements you’re putting in there, it’s also about how you make that powder into the correct and optimized feedstock,” White said.
The tour also gave visitors a glimpse into the future of refrigeration, by abandoning vapor compression for something entirely new: a solid-state caloric system. Efforts toward this goal has been roughly 20 years in the making after scientists have been searching for compounds that can generate strong cooling effects when cyclically acted upon by magnetic, electric or mechanical forces.
Vitalij Pecharsky, lead scientist on the project, likened it to replacing a incandescent light bulb with an LED bulb, ensuring a more sustainable and efficient method for refrigeration. While the work is still in it’s experimental phases, the group hopes to adopt the method into manufactured systems and products such as refrigerators and coolers — within a decade.
Following the tour, Simmons lauded the Ames Lab for its work, and fostering of the next wave of scientists at ISU.
“It is great to see the Ames Lab’s collaboration with Iowa State, working with students to help them see the possibilities of what there is in (STEM and manufacturing field),” Simmons said.