RAPID SOLIDIFICATION OF CU-25AT-PERCENT NI-ALLOY - MOLECULAR-DYNAMICSSIMULATIONS USING EMBEDDED-ATOM METHOD

We have performed molecular dynamics simulations on rapid solidificati on of Cu-25at.% Ni alloy based on the analytic embedded atom model for alloys. Our results, from the Faber-Ziman structure factors being con sistent with experiments by Waseda, show that the present EAM potentia ls for Cu-25at.% Ni alloy can correctly describe interactions between atoms (Cu-Cu, Cu-Ni and Ni-Ni pairs), although the model parameters ar e obtained from only pure metals. Furthermore, we have examined struct ure evolution during rapid solidification based on some specific struc ture functions, such as the pair correlation function, the bond orient ational order, the pair analysis techniques and the angular distributi on function. Results show that with decreasing: temperature, icosahedr al ordering has been enhanced, and the fast cooling supports the local five-fold symmetry, the HCP- and FCC-types of atomic bonded pairs rat her than the BCC-type of bonded pairs. In addition, we have examined s everal polyhedral distributions, such as the icosahedra, defective ico sahedra etc., generated in the simulations.