Interfacial properties and crystal growth of Ni and Ni50Al50 from molecular dynamics simulations

Abstract

Molecular dynamics simulations are used to determine the properties of the crystal–liquid interfaces of Ni and Ni50Al50. The interfacial free energies and kinetic growth coefficients for different crystal orientations are estimated using simulations of crystal–liquid systems at the melting temperature Tm from time- and wavenumber-dependent capillary wave height–height correlation functions. Growth coefficients are also determined from non-equilibrium simulations using the free solidification method, which compares well with those obtained from analysis of capillary wave fluctuations. Crystal growth in pure Ni is about a factor of 10 faster than in the binary Ni50Al50 system. The interfacial properties of the B2 intermetallic crystal phase of Ni50Al50 exhibit much lower anisotropy than those of the face-centered cubic crystalline structure of Ni.