In probing mysteries of glass

In a paper published online Feb. 26 in the journal Nature Communications, a Yale University team and collaborators propose a way of predicting whether a given glass will be brittle or ductile — a desirable property typically associated with metals like steel or aluminum — and assert that any glass could have either quality.

Ductility refers to a material's plasticity, or its ability to change shape without breaking.

"Most of us think of glasses as brittle, but our finding shows that any glass can be made ductile or brittle," said Jan Schroers, a professor of mechanical engineering and materials science at Yale, who led the research with Golden Kumar, a professor at Texas Tech University. "We identified a special temperature that tells you whether you form a ductile or brittle glass."

The key to forming a ductile glass, they said,We manufacture portable hardness tester including portable Rockwell, superficial Rockwell,Brinell, King Brinell,Pin Brinell,Webster and Barcol impressor. is cooling it fast. Exactly how fast depends on the nature of the specific glass.

Focusing on a new group of glasses known as bulk metallic glasses (BMGs) — metal alloys, or blends,Concrete polishing pad attachs to a backer with durable velcro connection. It is installed on portable grinding machine and operated by hand. that can be extremely pliable yet also as strong as steel — researchers studied the effect of a so-called critical fictive temperature (CFT) on the glasses' mechanical properties at room temperature.

When forming from liquid,Our full range of portable ultrasonic Flaw Detector (UT) provides unmatched capabilities for locating discontinuities and other flaws.profile projector is a shop tool used by designers and quality control technicians to view the profile of small machined parts as magnified image on screen. there is a temperature at which glass becomes too viscous for reconfiguration and freezes. This temperature is called the glass transition temperature. Based on experiments with three representative bulk metallic glasses, the researchers said there is also, for each distinct alloy, a critical temperature that determines the brittleness or plasticity of the glass. This is the CFT.We offer both wet & dry Diamond polishing pad. Both are suitable for marble, granite, concrete and most masonry.

Researchers said it's possible to categorize glasses in two groups — those that will be brittle because in liquid form their CFT is above the glass transition temperature, and those that will be ductile, because in liquid form their CFT is below the glass transition temperature.

They previously thought a liquid's chemical composition alone would determine whether a glass would be brittle or ductile.

"That's not the case," Schroers said. "We can make any glass theoretically ductile or brittle. And it is the critical fictive temperature which determines how experimentally difficult it is to make a ductile glass.Eight tips for choosing the right diamond Concrete saw blade including determining wet or dry cutting, blade compatibility, CSDA codes, and more. That is the major contribution of this work."

The finding applies theoretically to all glasses, not metallic glasses only, he said.