Rheological and thermodynamic behavior of calcium aluminosilicate melts within the anorthite-wollastonite-gehlenite compatibility triangle

For melts within the compatibility triangle anorthite-wollastonite-gehlenite (An-Wo-Geh) (CaAl2Si2O8-CaSiO3-Ca2Al2SiO7), the relationships between the chemical composition, the melt structure, and the rheological and thermodynamic properties are studied for each of the boundary lines, i.e. the An-Wo, Wo-Geh and Geh-An join. The influences of the degree of polymerization of the structural network and the amount of Al-O-Al linkages on the fragility and the configurational entropy of the melts are studied along the boundary lines. For the An-Wo join, the degree of polymerization dominates the responses of both fragility and configurational entropy to compositional variations. For the Wo-Geh and Geh-An joins, the amount of the Al-O-Al linkages dominates those responses. It is found that the depolymerization of the structural network and the formation of Al-O-Al linkages increase the fragility of the melt and the degree of structural disordering.