New experiment opens window on glasses

Jun 10, 2013
Metallic glass - shiny, easy to mould and with a high strength-to-weight ratio.

(Phys.org) —For the first time, scientists have mapped the structure of a metallic glass on the atomic scale, bringing them closer to understanding where the liquid ends and the solid begins in glassy materials.

A study led by Monash University researchers and published in Physical Review Letters has used a newly developed technique on one of the world's highest-resolution to understand the structure of a zirconium (Zr)-based . The findings could help explain the mystery of why glasses, or disordered solids form.

At the liquid-glass transition, the melt doesn't become solid at a distinct point, but becomes gradually more viscous until it is rigid. When - such as graphite, salt and diamonds - form they become abruptly rigid as the atoms form a regular, periodic arrangement. Glass never develops into an ordered atomic arrangement,but seems to retain the disordered structure of the liquid, despite its solidity.

This gives glasses unique properties. Metallic glasses have a higher strength-to-weight ratio than aluminium and titanium alloys and are extremely promising structural materials with unique applications as biomaterials and .

Led by Dr Amelia Liu from Monash University's School of Physics and the Monash Centre for , the researchers found that the structure of this Zr-based glass was not random, but composed in large part by efficiently arranged 13-atom icosohedral clusters.

Icosahedra have 20 faces, 12 vertices and 12 axes of five-fold symmetry, which means they cannot be packed into an ordered three dimensional, crystalline structure.

"It has long been theorised that icosahedra were a key atomic motif in the structure of metallic glasses and could, in fact, underlie glass formation. We have provided the first experimental confirmation of this," Dr Liu said.

"Our findings also point the way towards understanding the from liquid to solid – a grand challenge in modern condensed matter physics."

The researchers - from Monash, the University of Melbourne, the Australian Synchrotron, Ames Laboratory and Iowa State University in the US – developed a new electron scattering technique. By analysing the diffraction patterns from nano-scale volumes in the glass, they were able to identify symmetries in individual atomic clusters in the Zr-glass. Previous techniques had not provided sufficient detail to do this.

Dr Liu said that the new technique can now be used to understand the structure of other glasses and help progress the study of disordered materials.

Explore further: Technique simplifies the creation of high-tech crystals

Related Stories

A new way of making glass

Nov 09, 2012

(Phys.org)—A new way to make glass has been discovered by a collaboration of researchers at the Universities of Düsseldorf and Bristol using a method that controls how the atoms within a substance are ...

Researchers find ordered atoms in glass materials

Oct 02, 2012

(Phys.org)—Scientists at Ames Laboratory have discovered the underlying order in metallic glasses, which may hold the key to the ability to create new high-tech alloys with specific properties.

Metallic glass: How nanoscale islands react under strain

May 08, 2013

Quick-cooling molten atoms give metal alloys a glassy, or random, atomic structure that generates higher elasticity and better wear- and corrosion-resistance than their crystalline alloy counterparts. However, ...

Recommended for you

New approach to form non-equilibrium structures

55 minutes ago

Although most natural and synthetic processes prefer to settle into equilibrium—a state of unchanging balance without potential or energy—it is within the realm of non-equilibrium conditions where new possibilities lie. ...

Nike krypton laser achieves spot in Guinness World Records

2 hours ago

A set of experiments conducted on the Nike krypton fluoride (KrF) laser at the U.S. Naval Research Laboratory (NRL) nearly five years ago has, at long last, earned the coveted Guinness World Records title for achieving "Highest ...

Unleashing the power of quantum dot triplets

6 hours ago

Quantum computers have yet to materialise. Yet, scientists are making progress in devising suitable means of making such computers faster. One such approach relies on quantum dots—a kind of artificial atom, ...

Chemist develops X-ray vision for quality assurance

6 hours ago

It is seldom sufficient to read the declaration of contents if you need to know precisely what substances a product contains. In fact, to do this you need to be a highly skilled chemist or to have genuine ...

The future of ultrashort laser pulses

7 hours ago

Rapid advances in techniques for the creation of ultra-short laser pulses promise to boost our knowledge of electron motions to an unprecedented level.

User comments : 0