Thermodynamics of viscous flow and elasticity of glass forming liquids in the glass transition range

Tanguy Rouxel (1)

1 IPR - Institut de Physique de Rennes

The elastic moduli of glasses from different chemical systems, including oxide, chalcogenide, oxynitride, and metallic, were investigated through the glass transition (T(g)), typically from 0.4 to 1.3 T(g). These data were used to interpret the temperature sensitivity of the shear viscosity coefficient obtained on the same materials. The relevant Gibbs free activation energy was estimated from the apparent heat of flow by means of the temperature dependence of the shear elastic modulus. The activation entropy associated with the viscous flow was also derived and was found to correlate with the fragile versus strong character of the glass forming liquids. Finally, the physicochemistry of the flow process was described on the basis of the glass network de-structuration which shows up through the temperature dependence of Poisson's ratio, and an expression for the shear viscosity coefficient is proposed which is chiefly based on the high temperature elastic behavior. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3656695]

Mots clés: aluminium alloys; aluminium compounds; aluminosilicate glasses; calcium compounds; chalcogenide glasses; copper alloys; elasticity; entropy; free energy; germanium compounds; glass transition; magnesium compounds; nickel alloys; palladium alloys; phosphorus alloys; plastic flow; Poisson ratio; shear modulus; silicon compounds; viscosity; vitrification; yttrium compounds; zirconium alloys

Domaines: Mécanique des matériaux [physics.class-ph]; Mécanique des matériaux [physics.class-ph]

Tanguy Rouxel. Thermodynamics of viscous flow and elasticity of glass forming liquids in the glass transition range. Journal of Chemical Physics, 2011, 135 (18), pp.184501-184501. ⟨10.1063/1.3656695⟩. ⟨hal-00829996⟩