10 ADVANCED MATERIALS & PROCESSES | JULY/AUGUST 2025 NEW ROD-SHAPED CRYSTAL IDENTIFIED Researchers at New York University (NYU) documented how crystals evolve from shapeless blobs to orderly structures in a new study. During their work, the team came across a rod-shaped crystal that had not been previously identified, naming it “Zangenite” after Shihao Zang, the team member who discovered it. To study their formation, some researchers use crystals made up of colloidal particles, which are small yet much larger than the atoms that make up other crystals. To learn how colloidal crystals form, the team ran experiments to observe how charged colloidal particles behave in different growth conditions as they transition from saltwater suspensions to fully formed crystals. By running numerous computer simulations, the scientists found that colloidal crystals form through a twostep process—amorphous blobs of TESTING | CHARACTERIZATION EXTENDED SLIP BANDS DISCOVERED Scientists at the University of California, Irvine recently added new information to the accepted model that governs the mechanics of slip banding, which produces strain marks in metals under compression. Their discovery offers a deeper understanding of the behavior of advanced materials important to energy, space, and nuclear applications. The researchers report the discovery of extended slip bands, a finding that challenges the classic model developed by physicists Charles Frank and Thornton Read in the 1950s. While the Frank-Read theory attributes slip band formation to continuous dislocation multiplication at active sources, the Irvine team found that extended slip bands emerge from source deactivation followed by the dynamic activation of new dislocation sources. The process that results in extended slip bands was observed at the atomic scale as researchers performed mechanical compression on micropillars of an alloy of chromium, cobalt, and nickel. Using scanning transmission electron microscopy and large-scale atomistic modeling, the team was able to view the confined slip band as a thin glide zone with minimal defects and the extended slip band with a high density of planar defects. “Our ability to capture these processes at atomic and nano- meter scales provides new insight into collective dislocation motion and microscopic deformation instability in advanced structural materials,” says associate professor Penghui Cao. “With the advent of new, advanced ‘supermaterials’ such as the CrCoNi alloy, a deep understanding of their behaviors is more critical than ever.” uci.edu. Testbed 80. Courtesy of Rolls-Royce. Zangenite is a hollow crystal structure named after the NYU graduate student who made its discovery. Courtesy of Shihao Zang. Top row: Formation of a confined slip band (C-SB) with localized glide on slip plane ABC. Bottom row: Generation of extended slip band (E-SB), which triggers partial slip and formation of twin boundaries (TB), stacking faults (SF), and hexagonal close-packed (hcp) regions, resulting in band thickening along the ABD plane. Courtesy of Penghui Cao and Hangman Chen/UC Irvine. Researchers at the University of Glasgow, U.K., built the NextSpace TestRig as the first dedicated facility for testing the structural integrity of polymers, ceramics, and metals to be 3D printed in space. The rig features a vacuum chamber for generating temperatures from -150° to 250°C and the facility is open to both academic and commercial clients worldwide. www.gla.ac.uk. Tescan Group, Czech Republic, an electron microscope manufacturer, announces a new collaboration with The University of British Columbia. Tescan USA will provide researchers with Mira, Tensor, and Amber electron microscopes. tescan.com. BRIEFS
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