First-principles investigation of the elastic, electronic, and thermodynamic properties of a nitrogen-doped (Ti0.75W0.25)C solid solution

Abstract

(Ti00.75W0.25)C and (Ti0.75W0.25)(C0.75N0.25) are the major components of hard materials used, for example, in cutting tools. The material properties of these components were investigated using first principle methods. The elastic constants and moduli indicated that (Ti0.75W0.25)C was expected to yield good mechanical properties, with the exception of a poor shear modulus, at working temperatures, around 800°C (1073K), relevant to cutting tool operation. The shear modulus worsened upon substitution of nitrogen for carbon due to unfavorable shifts in the material electronic and vibrational structures. From a thermodynamic perspective, (Ti0.75W0.25)(CN0.25) was more stable due to a lower free energy of formation at T<2000K.