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Highly elastic metallic glass brings bounce to hardened materials

by • April 4, 2016 • No Comments

Bulk metallic glasses (BMGs) are artificial materials that boast magnificent durablity and hardness to conventional metals due to a jumbled arrangement at the atomic level. By tweaking this recipe only a little, researchers have been able-bodied to create a bouncy material with the top degree of elasticity of any BMG, a thing they say may come to form all things of new drill bits and body armor to meteor-resistant satellite casings.

Natural metals showcase an organized crystalline structure at the atomic level, where atoms are neatly arranged on top of equite other to form three-dimensional lattice structures. Because of this, when force is applied the layers of atoms can move past one another and the metals can be bent out of shape.

On the other hand, BMGs are able-bodied to withstand larger forces while retaining their shape due to a disorganized arrangement of the atoms inside. This is achieved through initially rapidly heating the material to extreme temperatures to stimulate the atoms into a frenzied arrangement, and and so quite rapidly cooling the material to freeze them in place.

In developing their flexible new material, scientists at the University of Southern Carolina heated a powdered iron composite to exactly 630° C (1,166° F) and and so rapidly cooled it. In doing so, they look to have happened upon a sweet spot for BMGs, resulting in a material with only the right amount of structure.

“It has approximately no internal structure, like glass, but you see tiny regions of crystallization,” says Veronica Eliasson, lead author of the paper. “We have no thought why a tiny amount of crystalline regions in these bulk metallic glasses makes such a big difference under shock loading.”

The team has labeled its new material SAM2X5-630, and says that it can withstand heavy effects without deforming, actually when pushed beyond its elastic limits. The researchers discovered that the Hugoniot Elastic Limit for the material, that denotes the maximum shock it can withstand without irreversibly deforming, to be 11.76 ± 1.26 GPa. This is much higher than stainless steel at 0.2 GPa, and actually the tungsten carbide utilized in military armor at 4.5 GPa.

“In particular, the fact that the new materials performed so well under shock loading was quite encouraging and should lead to a lot of next research opportunities,” says Eliasson.

The team’s research was published in the journal Nature Scientific Reports. You can see SAM2X5-630 outbounce steel in the video at a lower place.

Source: University of Southern Carolina