Enthalpy of Mixing in Al–Tb Liquid

Carl Tackes,Shihuai Zhou,Ralph Napolitano

doi:10.3390/e19060290

Carl Tackes, Shihuai Zhou + Show 1 more

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https://doi.org/10.3390/e19060290

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Abstract

The liquid-phase enthalpy of mixing for Al–Tb alloys is measured for 3, 5, 8, 10, and 20 at% Tb at selected temperatures in the range from 1364 to 1439 K. Methods include isothermal solution calorimetry and isoperibolic electromagnetic levitation drop calorimetry. Mixing enthalpy is determined relative to the unmixed pure (Al and Tb) components. The required formation enthalpy for the Al3Tb phase is computed from first-principles calculations. Based on our measurements, three different semi-empirical solution models are offered for the excess free energy of the liquid, including regular, subregular, and associate model formulations. These models are also compared with the Miedema model prediction of mixing enthalpy.

Highlights

Phase selection pathways in glass-forming metallic liquids are influenced by the development of short- and medium-range order [1–10], which contribute to local energetics and dynamics
We turn to a container-less approach and employ electromagnetic method, a stable levitation condition is established with a specimen of known mass under vacuum method, a stable levitation condition is established with a specimen of known mass under vacuum levitation coupled with drop-calorimetry (EMLDC)
To establish additional for our enthalpy mixing measurements application of three different semi-empirical treatments, all arising from the general model the Al–Tb liquid phase, we consider appropriate models and examine the application

Summary

Introduction

Phase selection pathways in glass-forming metallic liquids are influenced by the development of short- and medium-range order [1–10], which contribute to local energetics and dynamics. Even in binary glass-forming systems, clear evidence of the influence of ordering in the liquid state has been reported [3–5,11–17]. The marginal glass-forming ability in the Al–RE (aluminum rare-earth) systems has been associated with ordering in the liquid phase [18–29]. We perform measurements of the enthalpy of mixing, ∆Hmix , for the liquid phase. These are compared with the regular, subregular, and associate [75] formulations for the mixing enthalpy

Calorimetry Experiments for the the Al–Tb

Incremental

Analysis and Discussion

Findings

Conclusions