Effect of Cr doping on the mechanical properties and electronic structure of WCoB ternary boride by first-principles calculations.

The lattice parameters, structural stability, mechanical properties, hardness and electronic structure of WCoB with Cr alloying were investigated by using first-principles calculations. The Cr atom was selected to replace 0, 1, 2, 3, 4 Co atoms in WCoB crystal and 0, 1, 2 Co atoms in W2CoB2 crystal. The calculated cohesive energy and formation enthalpy showed that all structures can retain good structural stability with different Cr doping content. The calculated mechanical properties showed Cr doping will decrease the shear modulus, Young’s modulus, bulk modulus and hardness, but increase the ductility. The larger number of valence electrons of Cr led to the increasing of bond covalence and population. According to the electronic structures analysis, the nonmetal–metal hybridization and metal–metal interactions contributed to relatively high toughness. [ABSTRACT FROM AUTHOR]