The CALPHAD technique was used to calculate the Al
![](/images/glyphs/BO7.GIF)
Ru binary phase diagram. The RuAl (B2) phase was described with the sublattice model (SL), also designated Compound Energy Formalism (CEF), as well as the Modified Sublattice Formalism (MSL), which describes the order disorder
transformation with one Gibbs energy function. The RuAl
6 phase was described as a stoichiometric phase and the remaining intermetallic phases (Ru
4Al
13, RuAl
2 and Ru
2Al
3) were modelled with the sublattice model. The solubility of Ru in (Al) was considered negligible. Good agreement was obtained between the calculated and the experimental phase diagrams.