Bell-shaped “dendrite velocity-undercooling” relationship with an abrupt drop of solidification kinetics in glass forming Cu-Zr(-Ni) melts

Abstract

Abstract We analyze the crystal growth kinetics of rapidly solidifying glass-forming Cu50Zr50 alloy melts. Formulating a dendrite growth model we predict all features of crystallization kinetics in Cu50Zr50 from thermodynamically controlled growth (governed by the change in Gibbs free energy on solidification) to the kinetically limited regime (governed by atomic attachment at the solid/liquid interface). Comparing critical undercoolings observed in the crystallization kinetics with experimental data on melt viscosity, atomistic simulation's data on liquid microstructure and theoretically predicted dendrite growth velocity allows us to conclude that the dendrite growth kinetics strongly depends on the cluster structure changes of the melt.