Researchers move to develop better metallic glass read more at here www.spinonews.com/index.php/item/1400-researchers-move-to-develop-better-metallic-glass

Researchers from the University of Bristol have used state-of-the-art computer simulation to test a theory from the 1950s that when atoms organize themselves into 3D pentagons they suppress crystallization.

Metallic glasses have the potential to revolutionize many commercial applications, they have many of the advantageous properties of conventional metals but are much tougher and harder.

This is unlike conventional metals which naturally form well-arranged ordered structures, called crystals. Metallic glasses can be far stronger. They have no faults between crystal grains.

Dr. Patrick Royall from the School of Chemistry, who led this research with colleague Dr. Jade Taffs, said, to manufacture these amorphous materials, we need to find a way to stop them from forming crystals.

Using computer simulation, researchers uncovered the mechanism by which five-fold symmetry (3D pentagons) in liquids inhibits crystallization.

Dr. Taffs said, when a crystal is in contact with its liquid, the atoms at the surface of each phase cannot satisfy their bonding constraints, they are "neither liquid nor solid".

This means the material must pay energy due to the lack of satisfied bonds at the interface between crystal and liquid, and this surface energy is much higher in the case of liquids with fivefold symmetry.

Dr. Royall added, Liquids crystallize through the spontaneous creation of small crystals, and this process is extremely dependent on the size of the surface energy of the crystals.

 

Identifying the mechanism by which crystallization may be suppressed is an important step in the development of metallic glasses, and may open the door to using metallic glass in applications from vehicles to spacecraft.