

Unusual Mechanical Behaviors of CrN Polymorphs from First Principles
Abstract
Mechanical properties and electronic structures of different CrN phases have been studied using density functional theory calculations. It is found that the trend of bulk modulus is completely different from that of shear modulus (and elastic constant C44), which shows that the underlying sources of incompressibility and hardness are fundamentally different. These unusual mechanical behaviors can be understood from the different roles of Cr 3d electrons in hydrostatic compression and shear deformation. The present work provides important insights into the origin of hardness, and thus can help us to design new superhard materials of transition metal compounds.
Keywords
incompressibility; hardness; electronic mechanisms, CrNText