Rheological Behavior of a New Amorphous Alloy (Al74Cu16Mg10)99,7Zr0.3

Abstract

A new amorphous alloy (Al74Cu16Mg10)99,7Zr0.3 was prepared the applying a melt-spinning technique. Temperature dependence of viscosity of the alloy was determined using data from a PerkinElmer TMS2 thermo-mechanical analyzer processed according to a methodology based on the Free Volume Model (FVM). The strength of the alloy was calculated according to the Yang equation and the glass-forming ability was calculated according to the values of the Angell index mA. The activation energy of crystallization and the activation energy of the glass transition were computed using data from differential scanning calorimetry and thermomechanical experiments respectively. The activation energy of crystallization Еx = 168 ± 3.7 kJ/mol, was found to be higher than the activation energy of the glass transition Еg = 156 ± 1.4 kJ/mol, which means a dominant contribution of the atomic transport barrier, compared to the nucleation barrier. The relatively high temperature interval of the supercooled melt state Tx-Tg = 32 K and the low viscosity values in the same range ƞ(Тg) = 3.40E + 11 Pa.s and ƞ(Тx) = 1.87E + 10 Pa.s would allow thermomechanical treatment of the alloy in the temperature range of supercooled melt.

Keywords

• amorphous alloy
• viscosity
• free volume model (fvm)
• activation energy
• crystallization
• glass transition