Volume sequences of characteristic atoms separated from experimental volumes of AuCu and AuCu3 compounds

The systematic science of alloys (SSA) is a framework of the total energy and total volume able to be separated. The volume sequences of characteristic atoms at the central sites of the basic clusters in the fcc-based Au-Cu system are separated out from the experimental volumes of L10-AuCu and L12-AuCu3 compounds at room temperature only, by nine volume V-functions. From these volume sequences, the volumes, volumes of formation, ordering (excess) volumes and volume mismatch degrees of the L10-AuCu, L12-AuCu3 and L12-Au3Cu compounds, Au3Cu-, AuCu- and AuCu3-type ordered alloys with maximal ordering degree, and disordered Au1−xCux alloys are calculated. Among these functions, only ordering volumes of the compounds and ordered alloys obtained by the 6th V-function are negative, i.e., the destruction of the superlattice is accompanied by an increase in volume, which is identical with the experimental results. Accompanying conclusions, the different descriptions of volumetric properties between traditional alloy theories and SSA framework are discussed.