Researchers at the University of California, Irvine, have broadened understanding of slip band formation, an essential process in material deformation. The study, published in Nature Communications, identifies two distinct types of slip bands in chromium, cobalt, and nickel alloys, challenging the decades-old Frank-Read model.
Previously, the Frank-Read theory linked slip band formation to continuous dislocation multiplication. However, UC Irvine scientists observed that extended slip bands form through source deactivation followed by new dislocation source activation. This discovery was made possible by recent advances in scanning transmission electron microscopy and atomistic modeling.
“We can capture these processes at atomic and nanometer scales,” said Penghui Cao, corresponding author and associate professor at UC Irvine. “This provides new insight into collective dislocation motion and microscopic deformation instability in advanced structural materials.”
Cao explained that understanding deformation banding is crucial, as it occurs in various materials and systems, including crystalline substances and geological faults.
“With the advent of new, advanced ‘supermaterials’ such as the CrCoNi alloy, a deep understanding of their behaviors is more critical than ever,” he noted. “This foundational knowledge will accelerate the discovery of materials with tailored and predictable mechanical properties to meet the rising demand for advanced materials resilient to the extreme environments across energy and aerospace sectors.”
This research involved contributions from faculty and graduate students from UC Irvine and received support from the U.S. Department of Energy, UC Irvine, and the National Science Foundation.
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