Thermodynamic Properties of V2AlX(X=C,N)Phase Researched by First-principles Calculation
The structure,electronic,phonon and thermodynamic properties of V2AlX(X=C or N)were investigated by first-principles calculations using PAW method.The structural and electronic properties of the V2AlX(X=C or N)were discussed.The supercell method of lattice dynamic was utilized to calculate the phonon dispersion curves,and the thermodynamic properties of the V2AlX(X=C or N)phase at elevated temperatures were predicted by quasiharmonic approximation.The results show that V2AlC and V2AlN have metallicity and the replacement of N atoms for C atoms can result in the decrease in the DOS at Fermi level.Both the ternary MAX phases V2AlC and V2AlN are dynamically stable.Furthermore,it is found that the thermodynamic properties of V2AlN are more excellent compared with that of V2AlC phase,and the bulk modulus of V2AlN is also higher than that of V2AlC.
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