Determination of third order elastic constants from Morse potential for a Nitinol shape memory alloy

The current paper determines the third order elastic constants of the Ni-Ti based shape memory alloy from Morse potential using second nearest neighbour embedded atomic model (2NNEAM) in LAMMPS Molecular Dynamics (MD) simulation package. The complexities involved in the current work are lack of experimental data, such as amount of stress induced for the first order martensitic phase transition and plane about which the phase transformation takes place, which in our current work is considered as the amount of vibrations that the inherent anharmonicity possessed by the Shape memory alloy (SMA) for the first order phase transition. It is further attempted to justify the third elastic constants that are evaluated using VRH approximation, but however VRH approximation lacked stability and hence it is concluded that Morse potential is suitable.