The formation enthalpies of rapidly quenched amorphous alloys in the Al-Y-Ni system

For the determination of formation enthalpies of rapidly quenched amorphous alloys in the Al-Ni-Y system solution calorimetry was used. The measurements were performed in a isoperibolic Calvet type calorimeter enabling to measure heats of solution of amorphous alloys in liquid aluminium. The formation enthalpies of amorphous alloys were measured for compositions which corresponded to three sections of the phase diagram of the Al-Ni-Y system: with constant concentration of yttrium - Al90-xY10Nix, with constant concentration of aluminium - Al80Y20-xNix and constant concentration of nickel Al80-xYxNi15. The values of the enthalpies of formation show strong chemical interaction between the components in the amorphous phase. It was found, that substitution of aluminium by nickel and yttrium resulted in an increase in negative values for the enthalpy of formation. It was observed earlier that amorphous alloys in the A1-Y system can be prepared by rapid quenching in a narrow concentration range for yttrium, whereas Al-Y-Ni system has considerably wider composition glass forming range. These facts indicate that strong chemical interaction between components is a substantial factor responsible for the glass-forming ability.