The strength of diamond

Abstract

Diamond is the hardest known material; however, its mechanical stability, in particular the yield strength σy, is not known. We report reproducible generation of plastic deformation of diamond at room and low temperatures. We determined σy=130–140GPa by measuring the pressure distribution over the diamond anvils and by using the theory of elasticity. Yielding in diamond is accompanied by a strong luminescence with a characteristic spectrum. Our findings may be used to extend the static pressure limit beyond the current value of about 300GPa(3Megabars).