News Release 

Flawless films of alumina glass flex without fracturing at room temperature

American Association for the Advancement of Science

Aluminum oxide glass can be rapidly deformed like metal - folded, twisted and stretched - without shattering, according to a new study, which evaluates this phenomenon at a small scale. The surprising findings, which reveal the conditions in which common oxide glasses could be made ductile at room temperatures, inform the future development of "indestructible" glass materials. Inorganic oxide glasses are an important material in a variety of modern electronics; many of their functional properties, like electrical conductivity, for example, can be tailored for specific uses while maintaining the material's transparency. However, conventional oxide glasses are highly brittle at room temperature and easily shatter under stress. Thus, improving the strength and ductility of oxide glasses has been a sort of "holy grail" for engineers; "...many aspects of today's daily life and some of society's major challenges would directly and rapidly benefit from significant improvements on the mechanical reliability of glass products," writes Lothar Wondraczek in a related Perspective. Erkka Frankberg and colleagues demonstrate that thin films of amorphous aluminum oxide (a-Al2O3) glass can be permanently bent and pulled under high stress without breaking at room temperatures, showing the material can be substantially more ductile than previously believed. Direct microscopy and simulated observations reveal that the high plasticity of a-Al2O3 requires the material to be dense and flawless, illuminating key criteria that could identify other oxide glasses with similar malleability. The study shows that aspects of generating plasticity - features like bond rupture and mechanical relaxation, for example - have not been sufficiently well-understood, writes Wondraczek, who also says, "It is clear that it will not be easy to put to use these findings in the design of commodity glass products just now." According to Frankberg et al., the results suggest that oxide glasses are not inherently brittle; rather our ability to manufacture such a flawless glass in bulk and at larger scales is lacking.

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