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Superstrong metallic glass developed


January 11, 2011

Main image shows extensive plastic shielding of an initially sharp crack. Inset is a magnified view of a shear offset (arrow) developed during plastic sliding before the crack opened. 
Image: Robert Ritchie and Marios Demetriou

Main image shows extensive plastic shielding of an initially sharp crack. Inset is a magnified view of a shear offset (arrow) developed during plastic sliding before the crack opened. Image: Robert Ritchie and Marios Demetriou

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It seems hard to believe that glass could be stronger than steel, but a team of researchers has developed a super-strong metallic glass that has incredible plasticity when placed under stress, making it as strong and tough as metal. Typically, the structure of glass is strong but brittle which can cause cracks to develop and spread. The new metallic glass features palladium which has a high “bulk-to-shear” stiffness ratio. This allows the metallic glass to bend rather than crack – giving it a fracture toughness that goes beyond the limits of some of the strongest and toughest materials known.

The team from the Berkeley Lab and the California Institute of Technology (Caltech) created a pure glass material with a unique chemical composition that when placed under pressure, makes the glass form multiple shear bands rather than developing a crack. This property makes it much more damage-tolerant than other metallic glass.

Robert Ritchie, a materials scientist who led the Berkeley contribution to the research, said, “These results mark the first use of a new strategy for metallic glass fabrication and we believe we can use it to make glass that will be even stronger and more tough,”

“Because of the high bulk-to-shear modulus ratio of palladium-containing material, the energy needed to form shear bands is much lower than the energy required to turn these shear bands into cracks,” Ritchie said, “The result is that glass undergoes extensive plasticity in response to stress, allowing it to bend rather than crack.”

Initially, the Berkeley-Caltech collaboration made a metallic glass where the propagation of cracks was blocked by micro-structural barriers. This new work produced a glass that increased plasticity ahead of an opening crack, through the addition of palladium. The initial samples of the glass were microalloys of palladium with phosphorous, silicon and germanium, this yielded glass rods that were about one millimeter in diameter. By adding silver the researchers were able to expand the thickness of the rods to six millimeters.

“The rule of thumb is that to make a metallic glass we need to have at least five elements so that when we quench the material, it doesn’t know what crystal structure to form and defaults to amorphous,” Ritchie said.

Ritchie co-authored the paper, “A Damage-Tolerant Glass”, published in the journal, Nature Materials, which described the research. The other co-authors were Marios Demetriou (who actually made the new glass), Maximilien Launey, Glenn Garrett, Joseph Schramm, Douglas Hofmann and William Johnson of Caltech.

The new metallic glass was fabricated by co-author Demetriou at Caltech in the laboratory of co-author Johnson. Characterization and testing was done at Berkeley Lab by Ritchie’s group.


Okay, so what is the opacity? Can you see through it?

Paul Anthony

Hahahahahah .. Does anyone remember this being foretold in Star Trek IV when a 20th century glass worker was shown the secret formula by Scotty for \"transparent aluminum?!\"


Two words: transparent aluminum.

show me

The formula for transparent aluminum is already science fact.

Go here: http://science.howstuffworks.com/transparent-aluminum-armor3.htm

Known commercially as ALON, transparent aluminum armor is made of aluminum oxynitride, a combination of aluminum, oxygen and nitrogen. Before it can end up as a hard transparent armor plate, it begins as a powder. This powder is then molded, subjected to high heat and baked, just as any other ceramic is baked. Once baked, the powder liquefies and then quickly cools into a solid, which leaves the molecules loosely arranged, as if still in liquid form. The resulting rigid crystalline structure of the molecules provides a level of strength and scratch resistance that\'s comparable to rugged sapphire. Additional polishing strengthens the aluminum alloy and also makes it extremely clear.


In the future we will all talk to our mouses =) and have transparent palladium =)


Wow! Florida coast residents will love it. Could be a great replacement for shutters for hurricanes.


just always have your towel with you.

David Larson

Re super strength glass. We wont be able to make a huge quantity of this as Palladium is a rare earth metal together with Platinium also the reason there will not large quantities of this used in fuel cells. Cheers John M

John M

@Paul Anthony -- That is the exact first thought that I had when I read the article! lol.


Once again an Irwin Allen technology comes to pass. In the novel version of "Voyage to the Bottom of the Sea" the windows at the bow of Seaview were described as being made of "Herculite" a transparent metal devised by Admiral Nelson.

Neil R

Reminds me of the material used for ship hulls in Larry Niven's Ringworld series. Transparent and stronger than metal.

Neil Armstrong

transparent cars? what is the weight to strength ratio between the glass and steel? tensile strength? Compression? Shock? Does it need to be polished to become transparent? Can chemicals be added to color it?

I can forsee this being used for cellphone displays and camera lenses!

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