There’s some nifty research from the University of Bayreuth, together with partners in China and the U.S., on creating supremely tough aluminosilicate glass that boasts an unusual structure. The image above represents regular glass structure on the left, and the paracrystalline structure on the right.
Aluminosilicate, which contains silicon, aluminum, boron and oxygen, is a type of oxide glass. Oxide glasses are a group to which borosilicate and other common glasses belong. Structurally speaking, these glasses all have a relatively disordered internal structure. They’re known for their clarity, but not especially their durability.
One thing scientists have learned over time is that unusual things tend to happen under high pressures. In this case, researchers discovered temperatures around 1000°C and pressures between 10 and 15 gigapascals (a tremendous but not absurd amount of pressure) caused silicon, aluminum, boron and oxygen atoms to group together in a way that is clearly not fully crystallized, but is still different from the usual irregular structure of glass. This paracrystallization remains even after pressure and temperatures drop.
What does this mean? It means a toughness never before recorded in oxide glasses, and it doesn’t even really affect how clear the glass is. When subjected to forces that would normally cause cracks or fractures, these stresses are instead absorbed by the paracrystalline structures, which themselves transform back into the amorphous, random structure more usually seen in glass. Check out the research paper Toughening oxide glasses through paracrystallization to learn more.
Despite the name, aluminosilicate glass isn’t transparent aluminum. This may not be something one will do in a home workshop anytime soon, but it’s still pretty nifty.