A first-principles study of the stability and mechanical properties of Mo1-xWxC carbides
Metal carbides,as the reinforcing phase of the matrix,play a crucial role in the mechanical properties of steel.A first-principles approach based on density generalized theory is used to construct a Mo1-xWxC(0≤X ≤ 1)carbide model by virtual crystal approximation to calculate the property parameters,such as lattice con-stants,formation energy,binding energy,elastic constant,elastic modulus,Poisson's ratio u,Vickers hardness,and density of electronic states of Mo1-xWxC.The effects of W elements on the stability and mechanical proper-ties of MoC carbides were analyzed.The calculated values are in good agreement with other theoretical and ex-perimental values;the lattice constants increase with the increase of W content,the formation energy and binding energy of Mo1-xWxC are negative,and the absolute values of binding energy and formation energy increase with the increase of W content.The Mo1-xWxC with different doping contents satisfy the Born criterion and are me-chanically stable.the elastic constants,bulk modulus,Youngs modulus and shear modulus of Mo1-xWxC in-crease linearly with the increase of W content,and the B/G and Poisson's ratio decrease.The density of states values of Mo1-xWxC at the Fermi energy level are not zero,and the density of states values decrease with the in-crease of W content.Mo1-xWxC can form spontaneously and exists stably.The stability,elastic modulus,hard-ness and wear resistance of Mo1-xWxC carbides increase with the increase of W content,Mo1-xWxC is brittle,and the brittleness increases with the increase of w content.
First PrincipleVirtual crystal approximationMo1-xWxCMechanical properties
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