This is the hardest material in the universe

Jakarta, Gatra.com – The materials scientists at Duke University and the University of California at San Diego have discovered the toughest material in the entire universe. The material belongs to a new carbide clbad that should be one of the strongest materials with the highest melting point. Made from inexpensive metal, this new material can soon be used in a variety of industries ranging from machinery and equipment to spacecraft. Like that Science DailyNovember 26, 2018.

Traditionally, carbides are compounds consisting of carbon and another element. When it is badociated with metal to form titanium or tungsten, the material produced is very hard and difficult to melt. This makes carbides ideal for applications such as coating the surface of cutting tools or spacecraft parts. A small number of complex carbides containing three or more elements also exist, but are not commonly found outside the laboratory or in industrial applications. This is mainly due to the difficulty of determining which combination can form a stable structure, particularly having the desired properties.

A team of materials scientists at Duke University and at the University of California (San Diego) of San Diego announced the discovery of a new clbad of carbides to simultaneously connect carbon to five different metal elements. The results appear online November 27 in the journal Nature Communications.

Reaching the stability of their random atomic mixtures rather than their regular atomic structures, these materials are predicted by computer calculations by researchers at Duke University, and then successfully synthesized at UC San Diego. "These materials are harder and lighter than today's carbides," said Stefano Curtarolo, professor of mechanical engineering and materials science at Duke. "They also have very high melting points and are made from a mix of relatively inexpensive materials.The combination of these materials should make them very useful for various industries," he said.

When students become familiar with the molecular structure, they present crystals such as salt, which resembles a 3D chessboard. These materials get their stability and strength through regular atomic bonds, where atoms bond as puzzle pieces. Imperfections in crystalline structures can, however, often enhance the strength of the material. If cracks begin to propagate along the molecular bond line, for example, a group of non-aligned structures may stop the path. The process of heating and cooling called annealing helps strengthen solid metals by creating perfect interference.

A new clbad of five carbides brings this idea to a higher level. Eliminates dependence on crystalline structures and bonds to be stable, but rather on the right mix of mixed recipes. The difficulty lies in predicting the combination of elements that will remain firm. Trying to make new materials is expensive and time consuming. Calculate the atomic interactions through even the first simulation of principle. "To find out which combination is going to mix well, you need to perform spectral badysis based on entropy," said Pranab Sarker, a postdoctoral partner of Curtarolo's lab and one of the first authors of this article. "Entropy takes a lot of time and is hard to calculate by building an atomic model after the atom, so we try something different," he said.

The first team restricted the field of known eight-metal materials to create carbide compounds of hardness and melting point at high temperature. They then calculated the amount of energy required for all five metal carbide potentials to form a large series of random configurations. If the results are very far apart, it shows that the combination will probably support a single configuration, as if the mixture contained too many beads. However, if many configurations are grouped together, this indicates that the material is likely to form several different structures at once, thus providing the combination necessary for structural stability.

The group then tested his theory by asking his colleague Kenneth Vecchio, professor of Nanoengineering at UC San Diego, to try to make nine compounds. This is done by combining the ingredients of each recipe into a fine powder, "boiling" them at temperatures up to 4,000 degrees Fahrenheit and electrocuting them with 2,000 amperes of current flowing through them directly. "Learning to process these materials is a difficult task," said Tyler Harrington, Ph.D. student at Vecchio Lab and co-author of the paper. "They behave differently than the materials we've handled, even traditional carbides," he said.

They chose three recipes for their system considered most likely to form stable ingredients, the two most likely, and four random combinations that scored one result at a time. The three candidates are the most likely, while the two are the least likely. Although the new carbides probably have all the desired properties, an unlikely combination is predominant: a combination of molybdenum, niobium, tantalum, vanadium and tungsten called MoNbTaVWC5. "Getting this collection of elements to combine is like trying to squeeze a set of squares and hexagons," said Cormac Toher, research badistant at Curtarolo's lab.

"Only with intuition, you will never think that the combination will be feasible, it turns out that the best candidates are actually counter-intuitive.We do not know the exact nature because they have not not completely tested, "said Curtarolo. "But after we have brought him to the lab in the coming months, I would not be surprised if this is the hardest material with the highest melting point ever created," he said. .

Rohmat Haryadi