Breakthrough at UC Irvine Challenges Decades-Old Theories

Scientists at the University of California, Irvine, have made a groundbreaking leap in our understanding of material deformation, uncovering extended slip bands that could reshape the future of advanced materials critical for energy systems, space exploration, and nuclear applications.

The Classic Theory Under Fire

In a recent publication in Nature Communications, researchers from UC Irvine's Samueli School of Engineering have challenged the classic slip band model created in the 1950s by physicists Charles Frank and Thornton Read. While the Frank-Read theory suggested that slip bands form through continuous dislocation multiplication at active sources, the UC Irvine team discovered that these extended slip bands actually originate from the deactivation of sources followed by the dynamic activation of new dislocation points.

Seeing Deformation at the Atomic Level

Utilizing advanced scanning transmission electron microscopy and large-scale atomistic modeling, the researchers examined microscopic pillars made from an exceptionally tough alloy of chromium, cobalt, and nickel. This innovative approach allowed them to visualize the confined slip band as a thin glide zone with minimal defects, while the extended slip band exhibited a high density of planar defects.

A New Perspective on Material Behavior

"The full dynamics of slip band formation had eluded us for over 70 years," stated Penghui Cao, the study's lead author and an associate professor of mechanical and aerospace engineering at UC Irvine. "Capturing these processes at atomic and nanometer scales gives us valuable insight into collective dislocation motion and microscopic deformation instability in advanced materials."

Implications for Advanced 'Supermaterials'