8 ADVANCED MATERIALS & PROCESSES | SEPTEMBER 2025 team discovered that liquid carbon exhibits far more complex crystallization behavior than previously thought. Most surprisingly, they found that graphite can form spontaneously even when diamond should be the stable phase, possibly derailing diamond formation. In the study, the team prepared models at various pressures from 5 to 30 GPa as the molten carbon cooled from 5000 to 3500K. While the team expected to get glassy carbon from the rapid quench of the liquid, they noticed spontaneous crystallization. At high pressures, the liquid carbon crystallized into diamond, and at lower pressures, it crystallized into graphite. Researchers found that graphite acts as a steppingstone in diamond formation because its structure more closely resembles liquid carbon’s density and bonding patterns. Through the simulations, the team also revealed the molecular structures TESTING | CHARACTERIZATION ULTRASOUND SPOTS ALUMINUM INCLUSIONS Researchers at Fraunhofer IZFP, Germany, developed a new measuring system for aluminum foundry cus- tomers to detect contamination in molten metal. “The purity of the molten metal, whose temperature ranges from 600-800°C, is hugely important to the final product. For example, any ceramic particles that may be present in the melt don’t liquefy until they get to a temperature of 2000° or more, and they remain in the finished component as inclusions if they aren’t deliberately removed. This can lead to cracks and holes, and thus in the worst case to component failure,” says scientist Thomas Waschkies. The team decided to develop a mobile, ultrasound-based measure- ment system for molten aluminum to address these challenges. The AloX project was launched, with the name derived from aluminum melt and oxide inclusions. “It’s a lot like a car parking sensor in that the system, immersed in the molten metal, transmits signals that then bounce off a reflector. If any particles—meaning contaminants—float by, there is a disruptive signal,” says researcher Andrea Mross. Those signals make it possible to react on the production floor to assure quality. Working closely with industry, the team developed an initial prototype. The measuring trolley features a special unit equipped with ultrasonic waveguides and built-in cooling, along with a dedicated software program featuring a patented analysis algorithm for de- tecting inclusions. www.fraunhofer.de. MOLECULAR SIMULATIONS EXPLORE CARBON FORMATION Scientists at the University of California, Davis and George Washington University are investigating how molten carbon crystallizes into either graphite or diamond at temperatures and pressures similar to the Earth’s interior. Using machine learning- powered molecular simulations, the Testbed 80. Courtesy of Rolls-Royce. Simulations show the nucleation pathways of graphite (top row) and diamond (bottom row) from direct molecular dynamics simulations at pressures of 15 and 15.5 GPa and a temperature of 3650K. Courtesy of Davide Donadio/UC Davis. Thomas Waschkies and Andrea Mross received the Joseph von Fraunhofer Prize for 2025 for developing the AloX mobile ultrasoundbased measuring system. Courtesy of Piotr Banczerowski/Fraunhofer. Lawrence Livermore National Laboratory researchers and colleagues measured the structure of liquid carbon for the first time. Experiments were conducted with the DiPOLE 100-X high-energy laser at the European X-ray Free-Electron Laser (XFEL) facility. DiPOLE was used to shock compress and liquify a glassy carbon sample while XFEL measured its structure. llnl.gov. Wabtec Corp., Pittsburgh, acquired Evident’s inspection technologies division, Waltham, Mass., formerly part of the scientific solutions division of Olympus Corp. The purchase expands Wabtec’s digital intelligence business with products for the rail, mining, and industrial sectors. wabteccorp.com. BRIEFS
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