Why diamond is very hard

摘要

Diamond is mechanically exceptional in three ways. First, it resists volume changes more than any other known substance (it has an exceptional bulk modulus, B). Second, it resists shear stress more than any other substance; and its octahedral shear modulus is 14% larger than B. Third, it is harder (scratching, and,or indentation) than anything else. Simple quantitative theories of the bulk modulus, the shear modulus, and the stress t needed to move dislocations in diamond are developed. and compared, with experimental measurements. [References: 8]