ADVANCED MATERIALS & PROCESSES | MARCH 2024 6 METALS | POLYMERS | CERAMICS On January 25, thyssenkrupp Materials de México inaugurated a $37 million service center in San Luis Potosí, Mexico. Among the benefits of the new facility is a Schuler processing line that enables cutting raw pieces of aluminum and high-strength steel for lightweighting applications in the automotive industry. thyssenkrupp.com. POLYMER NETWORKS DAMPEN SOUND In a quest to better understand how network connectivity and bond exchange mechanisms govern the overall damping behavior of polymer networks, researchers at the University of Illinois Urbana-Champaign synthesized networks with two distinct architectures and crosslink points capable of dynamically exchanging polymer strands. The incorporation of dynamic bonds into the polymer network demonstrates excellent damping of sound and vibrations at well-defined frequencies. The ability to tailor polymers that absorb specific frequencies can be beneficial for use in ear plugs and helmets, as well as in scenarios with repeat exposure to a certain frequency of noise. “The key advance here is that we’re using dynamic covalent bonds,” explains lead researcher Chris Evans. Incorporating orthogonal bonds, where fast bonds can only exchange with other fast bonds and slow bonds can only exchange with other slow bonds, generates multiple and well-separated relaxation modes, giving the network excellent damping and improved mechanical properties. FILMING ATOMIC HYDROGEN FLOW A group of researchers at Tohoku University, Japan, developed a simple and inexpensive method to visualize the atomic state of hydrogen. Increased integration of hydrogen-based energy requires overcoming some significant technical issues—necessitating structural and functional materials that produce, store, transport, and preserve hydrogen. To develop advanced materials for hydrogen-related applications, a fundamental understanding of how hydrogen behaves in alloys is crucial. The group’s new visualization technique utilizes an optical microscope and a polyaniline layer, enabling researchers to successfully film the flow of hydrogen atoms in pure nickel (Ni). The color of polyaniline changed from purple to white when reacting with hydrogen atoms in a metal, and in-situ visualization revealed that hydrogen atoms in pure Ni preferentially diffused through grain boundaries in disordered Ni atoms. Furthermore, the group found that hydrogen diffusion was dependent on the geometrical structure of the grain boundaries—the hydrogen flux grew at grain boundaries with large geometric spaces. These results experimentally clarified the relationship between the atomic-scale structure of pure Ni and the hydrogen diffusion behavior. The approach has broader applications as well. It can be applied to other metals and alloys, such as steel and aluminum, and drastically facilitates elucidating the microscopic hydrogen-material interactions, which could be further investigated through simulations. According to the researchers, understanding hydrogen behaviors related to the atomic-scale structure of alloys will enable more efficient alloy design, dramatically accelerating the development of highly functional materials and a shift toward a more hydrogen energy-based society. www. tohoku.ac.jp/en. Stardust Power Inc. will break ground on a $1 billion battery-grade lithium refinery in Muskogee, Okla., by mid-2024. The facility will serve as a central location for lithium inputs to be delivered and refined into lithium products for delivery across the U.S. stardust-power.com. BRIEFS Researchers have discovered a technique for depicting the microscopic flow of hydrogen atoms in metal. Courtesy of Tohoku University. Materials science and engineering professor Chris Evans. Courtesy of the University of Illinois UrbanaChampaign.
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