A DFT study on effects of W solution on cemented carbides Co phase pressurized properties

Abstract Effects of W solution (3 at.%) on the structure, elastic properties, and structural phase transition of Co under pressure were investigated in this paper by first principles calculations. The lattice constants of pure Co and Co–W alloy, both with fcc and hcp structure, gradually decrease with the increasing pressure. In general, the bulk modulus(B), shear modulus(G) and Young's modulus(E) of pure Co and Co–W alloy increase approximately linearly with the increasing pressure. W solution brings almost negligible impact on B of fcc and hcp Co, however, effect of W solution on G and E can not be neglected. It is worth to mention that B, G, and E for fcc Co and Co–W alloy are always higher than those for hcp Co and Co–W alloy at the same pressure. According to the calculated results, W solution can improve the ductility and thermodynamic stability of Co, and increase the hcp to fcc phase transition pressure from 102 GPa to 130 GPa.