A thermodynamic assessment of the copper–gallium system

A thermodynamic assessment of the Cu-Ga system was carried out by the CALPHAD approach (CALculation of PHase Diagram). The liquid phase, the solid solution phases of fcc (alpha-Cu) bcc (beta) and, hcp (zeta), the Solution compounds of Cu(9)Ga(4)_0 (gamma(o)), Cu(9)Ga(4)_1 (gamma(1)), Cu(9)Ga(4)_2 (gamma(2)) and Cu(9)Ga(4)_3 (gamma(3)), the stoichiometric compounds Of Cu(0.778)Ga(0.222) (zeta') and CuGa(2), and the terminal phase of orthorhombic-Ga were taken into consideration in the optimization. The substitutional solution model was used for the liquid phase and the solid solution phases of fcc, bcc and hcp. The solution compounds related to Cu(9)Ga(4) were described with the sublattice model. The order-disorder transformation between CugGa(4)_0 (gamma(0)) and Cu(9)Ga(4)_1 (gamma(1)) was considered. In the model description of Cu(9)Ga(4)_2 (gamma(2)) and Cu(9)Ga(4)_3 (gamma(3)), vacancies were considered. Differential scanning calorimetric analysis was conducted to obtain phase transformation temperatures and the enthalpies of fusion of Cu-Ga alloys. A set of self-consistent thermodynamic parameters were obtained and the calculated phase diagram and thermodynamic properties were presented and compared with experimental data. (C) 2008 Elsevier Ltd. All rights reserved.