{"id":12963,"date":"2017-01-06T05:39:41","date_gmt":"2017-01-06T05:39:41","guid":{"rendered":"http:\/\/www.kurzweilai.net\/?p=291931"},"modified":"2017-01-13T05:41:22","modified_gmt":"2017-01-13T05:41:22","slug":"mit-researchers-design-one-of-the-strongest-lightest-materials-known","status":"publish","type":"post","link":"https:\/\/hoo.central12.com\/fugic\/2017\/01\/06\/mit-researchers-design-one-of-the-strongest-lightest-materials-known\/","title":{"rendered":"MIT researchers design one of the strongest, lightest materials known"},"content":{"rendered":"
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3-D-printed “gyroid” models such as this one were used to test the strength and mechanical properties of a new lightweight material (credit: Melanie Gonick\/MIT)<\/p><\/div>\n

MIT scientists said today they’ve just created one the strongest materials known (ten times stronger than steel, but also one of the lightest, with a density of just 5 percent of that of steel) by compressing and fusing flakes of graphene, a two-dimensional form of carbon.<\/p>\n

In its two-dimensional form, graphene is thought to be the strongest of all known materials. But researchers until now have had a hard time translating that two-dimensional strength into useful three-dimensional materials.<\/p>\n

It’s all about the geometrical configuration<\/strong><\/p>\n

But it’s not about the material itself; it’s about their unusual 3-D geometrical configuration, the researchers discovered. That suggests that similar strong, lightweight materials (in addition to graphene) could be made from a variety of materials by creating similar geometric features.<\/p>\n

\u201cYou can replace the material itself with anything,\u201d\u00a0says Markus Buehler, the head of MIT\u2019s Department of Civil and Environmental Engineering (CEE) and the McAfee Professor of Engineering. \u201cThe geometry is the dominant factor. It\u2019s something that has the potential to transfer to many things.\u201d<\/p>\n

The findings were reported today an open-access paper<\/a> in the journal\u00a0Science Advances<\/em>.<\/p>\n

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This illustration shows the simulation results of\u00a0 compression (top left and i) and\u00a0tensile (bottom left and ii) tests on 3-D graphene (credit: Zhao Qin)<\/p><\/div>\n

By analyzing the material\u2019s behavior down to the level of individual atoms within the structure, the engineers were able to produce a mathematical framework that very closely matches experimental observations.<\/p>\n

Two-dimensional materials \u2014 basically flat sheets that are just one atom in thickness but can be indefinitely large in the other dimensions \u2014 have exceptional strength as well as unique electrical properties. But because of their extraordinary thinness, \u201cthey are not very useful for making 3-D materials that could be used in vehicles, buildings, or devices,\u201d says Buehler. \u201cWhat we\u2019ve done is to realize the wish of translating these 2-D materials into three-dimensional structures.\u201d<\/p>\n

The trick: heat + pressure<\/strong><\/p>\n

The solution for compressing small flakes of graphene turned out to be a combination of heat and pressure. This process produced a strong, stable structure whose form resembles that of some corals and microscopic creatures called diatoms. These new shapes, which have an enormous surface area in proportion to their volume, proved to be remarkably strong.<\/p>\n

Buehler says the process resembles what would happen with sheets of paper. Paper has little strength along its length and width, and can be easily crumpled up. But when made into certain shapes, for example rolled into a tube, suddenly the strength along the length of the tube is much greater and can support substantial weight. Similarly, the geometric arrangement of the graphene flakes after treatment naturally forms a very strong configuration.<\/p>\n