Calorimetric measurements and assessment of the binary Cu–Si and ternary Al–Cu–Si phase diagrams

Abstract

Using dynamic scanning calorimetry the temperature, composition and reaction enthalpy of a number of invariant reactions in the Cu–Si and Al–Cu–Si systems were determined. The temperatures and compositions are in good agreement with previous experimental data. Reaction enthalpies have not been previously measured. The Cu–Si system was thermodynamically modelled in detail using all available data. Experimental data are well reproduced, including the presently measured reaction enthalpies. Compared to the best previous thermodynamic description some improvements could be achieved. The Al–Cu–Si system was tentatively modelled using a new model for the γ-Al4Cu9 phases and without using large ternary interactions with large temperature dependencies. The Cu-rich part is very complex and the complete system could be reasonably described. Though it was not possible to present a detailed assessment in this work there are important improvements compared to previous thermodynamic descriptions.