Structure and properties of clusters in FCC materials

Abstract

Properties of small clusters with icosahedric symmetry, isolated or embedded in an fcc matrix, were investigated for different metals by the molecular-dynamics method. It is shown that the energy specific features of clusters and the height of the barrier for the transition from an fcc to icosahedric structure for isolated clusters are determined to a great extent by the properties of the interatomic-interaction potentials. In this case, the lower the transition barrier, the “softer” the potential is. Vice versa, the clusters embedded in a matrix are most stable in metals with a rigid potential. It is established that the stability of an embedded cluster increases the number of vacancies at the boundary between two structures and depends on the orientation of the cluster with respect to the matrix. An embedded cluster introduces significant perturbations into the surrounding matrix, which extend to distances of about one and a half cluster sizes.