Nb 掺杂对 Mo2 FeB2弹性, 硬度和 电子结构影响的第一性原理计算.

Mo2 FeB2 is a good boron based cermet material with high temperature resistance, wear resistance and high strength. It has broad application in the field of mould. The structural stability, elastic properties, hardness and electronic structure of Mo2 FeB2 with Nb alloying were investigated by using first-principles calculations. The calculated cohesive energy and formation enthalpy showed that Nb prefers to occupy the Fe site of Mo2 FeB2, and the Nb at Fe site of Mo2 FeB2 possesses better mechanical properties compared with that at Mo site. Moreover, the calculated results showed that Nb doping could increase the shear modulus, Young’s modulus, bulk modulus and hardness, but slightly decrease the ductility. The suitable doping concentration should be 2.5 at. %. The calculated electronic structure indicated that the increase of mechanical properties is attributed to the formation of Nb-B covalent bonds. [ABSTRACT FROM AUTHOR]