On the partial atomic volume of aluminum in solid solutions based on the 3d transition metals and copper

The composition dependence of the average atomic volume, as well as of the enthalpy of formation, was investigated for the aluminum-containing systems with the 3d transition metals and copper. The partial atomic volume of aluminum and the partial molar enthalpy of aluminum were determined for the transition metal-based solid solutions. Independent of the type of solid-solution structure, the (negative) partial molar enthalpy of aluminum increases and the partial atomic volume of aluminum decreases with increasing filling of the 3d band. The charge transfer and the bonding in solid solutions exhibiting close-packed structures (coordination number (CN) = 12) is substantially higher than in solid solutions, based on the bee structure (CN = 8). The s electron of copper, though, reduces the charge transfer and the bonding in the fee solid-solution Cu(Al) significantly.