Crystal-Melt Interface Growth Velocity of Ni-Zr Alloys Through Molecular Dynamics Simulations

R Ramakrishnan and G Phanikumar and R Sankarasubramanian, TRANSACTIONS OF THE INDIAN INSTITUTE OF METALS, 68, 1113-1117 (2015).

DOI: 10.1007/s12666-015-0655-0

In this investigation, crystal-melt interface growth velocities of Ni-Zr alloys are investigated at different undercoolings using molecular dynamics simulation. Ni, Ni-0.1 at.% Zr and Ni-1 at.% Zr are considered and free solidification approach is adopted to measure the interface growth velocity. Further, the anisotropy in growth velocity is studied by considering three different crystalline planes, viz., (100), (110) and (111), interfacing with the liquid. MD simulations are carried out using LAMMPS software and the Finnis-Sinclair interatomic potential developed by Wilson and Mendelev is used to describe the interatomic interactions. It is observed that addition of small amount of impurity (0.1 % Zr) increases the interface growth velocity of pure Ni during solidification. However, with further increase in the solute content (1 % Zr), interface growth velocity decreases. In all the cases, (100) is the fastest growing interface while the close packed (111) has the slowest velocity. Further, the calculated interface velocities are compared with the predicted ones from the theoretical model of Broughton-Gilmer-Jackson.

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