Two-Dimensional Material Tougher than Graphene

Two-Dimensional Material which share similar properties with graphene appear to be tougher. The material is called hexagonal boron nitride and it is resistant to cracking that scientists are gobsmacked. The finding flies in the face of the fundamental description of fracture mechanics that scientists have been using to predict and define toughness since the 1920s.

Jun Lou of Rice university said that the scientist observed that the material is remarkable. Nobody expected to see this in Two-Dimensional Material.Hexagonal boron nitride is extremely similar to graphene. The two materials both consist of hexagonal lattices of atoms. In the case of graphene, all those atoms are carbon but for h-BN, each hexagon contains three boron atoms and three nitrogen atoms.

Carbon-carbon bonds are among the strongest, so it’s expected that the material would be much stronger than h-BN. The two materials have similar values for strength and elasticity, but h-BN’s are slightly lower. Graphene has a strength of about 130 gigapascals for strength and 1.0 terapascals for elasticity; h-BN’s values are 100 gigapascals and 0.8 terapascals.

Lou also explained that scientists measured the fracture toughness of graphene seven years ago, and were not very resistant to fracture. If you have a crack in the lattice, a small load will just break that material. The h-BN’s other properties are very similar to those of the material, its brittleness would also be comparable because graphene’s brittleness was consistent with the Griffith theory of fracture, laid out by engineer Alan Arnold Griffith in 1921. He found that cracks will propagate when the stress placed on material is greater than the force holding it together, and the difference in energy is released in the propagation of the crack