Elastic properties of binary NiAl, NiCr and AlCr and ternary Ni2AlCr alloys from molecular dynamic and Abinitio simulation

Molecular dynamic simulation is used in order to investigate the structural and elastic properties of binary metallic alloys NiAl, NiCr, AlCr and ternary Ni2AlCr. The classical model is a Sutton-Chen like potential from the embedded atom method scheme, that we fitted to equilibrium properties of the three binary phases. First principle calculations based on density functional theory and the full potential linear augmented plane waves method were carried to determine the binary phases properties used in the classical potential fitting procedure. The classical calculations carried in an NVT thermodynamical ensemble leads to the determination of lattice parameters, bulk modulus and elastic constants in a temperature range from 300 to 900 K for the four systems. The AlCr binary alloy was found to have the lowest strength and the largest thermal expansion, when NiCr has the largest hardness and Ni2AlCr the lowest thermal expansion. The general trend of the calculated elastic modulus was found to follow the correct physical behavior of metallic alloys. The accuracy of the potential at elevated temperatures is suggested to be limited.