Enthalpies of formation and lattice parameters of B2 phases in Al-Ni-X systems*
Rongxiang Hu, Hsin-Ning Su, and Philip Nash
Thermal Processing Technology Center, Illinois Institute of Technology (IIT),10 West 32nd Street, Chicago, IL 60616, USA
Abstract: Enthalpies of formation of Al-Ni-X (X: Fe, Ru, Pd, Pt, and Cu) alloys were measured by high-temperature calorimeter and compared with the calculated value from Miedema's model and interpolation models. The interpolation models generally provide better prediction than Miedama's model. No one interpolation model generated superior predictions. Lattice parameters of B2 phase compounds were determined by X-ray diffraction (XRD). The atomic volumes in the Al-Ni-Fe system were calculated and show that Fe substitutes preferentially on the Al sublattice. The heat content of Al0.5Ni0.2Ru0.3 and Al0.5Ni0.35Cu0.15 at high temperature was obtained, and the results are in good agreement with those heat capacities estimated by the Neumann-Kopp rule.
Keywords: Al-Ni-X alloys; Miedema's model; Neumann-Kopp rule; enthalpies of formation; B2 phase compounds; Al-Ni-Fe.
*Paper based on a presentation at the 12th International IUPAC Conference on High Temperature Materials Chemistry (HTMC-XII), 18-22 September 2006, Vienna, Austria. Other presentations are published in this issue, pp. 1635-1778.