An international team of researchers has discovered a class of metal alloys that won’t snap in extreme cold.

Materials science held the belief that metals naturally become brittle and shatter easily under extreme cold because their internal crystal defects lock up and prevent deformation. 

This new study reveals that experimental niobium-titanium alloys can defy this rule at a freezing -253°C (20 kelvin) by spontaneously shifting their atomic structure to form mirror-image twins and generate fresh defects. 

Researchers from UC Berkeley, Lawrence Berkeley National Laboratory, and the University of Oxford say this development could help design damage-tolerant components for aerospace, hydrogen transport, and deep-space applications.

“What surprised us is that these alloys remain remarkably damage tolerant even at 20 kelvin,” said Professor Dong Liu, Oxford corresponding author. 

Body-centered cubic metals like iron, tungsten, and chromium usually withstand mechanical stress through the smooth movement of microscopic defects known as dislocations within their crystal structure. 

These sliding defects give the material its fundamental flexibility, allowing it to bend and deform under pressure rather than snap. Standard metals need warm temperatures to keep their internal defects moving smoothly. Without this movement, the metal loses its flexibility in extreme cold. As a result, sudden freezing temperatures can cause materials to fracture easily.

The newly discovered alloys cheat the system. When conventional routes for movement freeze over, the metal opens entirely new microscopic pathways. Small regions of the crystal shift into mirror-image orientations — a phenomenon known as nanoscale “twinning.” This locally alters their crystal structure.

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