In this work we analyze the fragmentation of a (FCC) dendrites in the Al-Cu alloy for different compositions. We use the phase field model for the simulation of 2D and 3D dendrite solidification and consequent melting and fragmentation studies. Our efforts lie in understanding the dependence of temperature and the history of temperature cycling on the dynamics of fragmentation. We discuss our results with relation to theoretical analysis in literature and derive signatures for fragmentation dynamics of 3D dendrites. (C) 2012 Elsevier B.V. All rights reserved.