Canadian super-glass bends but doesn’t break

Researchers at McGill University’s Department of Mechanical Engineering announced a method for increasing the toughness of glass and other brittle materials by as much as 200 times.

According to Prof. François Barthelat, he and his team have successfully mimicked the micro-structure of seashells, and its strength, simply by etching the glass with a laser.

“Mollusk shells are made up of about 95 per cent chalk, which is very brittle in its pure form,” says Barthelat. “But nacre, or mother-of-pearl, which coats the inner shells, is made up of microscopic tablets that are a bit like miniature Lego building blocks.”

Barthelat’s team studied the internal “weak” boundaries or edges found in natural materials like nacre. They then used a laser to engrave wavy networks of 3D micro-fissures in glass slides. Counter-intuitively, the wavy groove patterns didn’t introduce increased brittleness, but instead prevented the glass from shattering by allowed it to deform slightly and absorb impact energy.

Although the McGill researchers experimented with glass slides, Barthelat says the process can be scale up to any size of glass sheet.

“What we know now is that we can toughen glass, or other materials, by using patterns of micro-cracks to guide larger cracks, and in the process absorb the energy from an impact,” says Barthelat. “We chose to work with glass because we wanted to work with the archetypal brittle material. But we plan to go on to work with ceramics and polymers in future.”

The full paper (Overcoming the brittleness of glass through bio-inspiration and micro-architecture) appeared in the journal Nature Communications.
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