Theoretical description of slow non-monotonic relaxation processes in Al-Y melts

TL;DR

This paper provides a theoretical framework using Cahn-Hilliard and non-equilibrium dynamics to explain slow, non-monotonic relaxation in Al-Y melts, attributing it to non-linearity and heterogeneity near the liquidus line.

Contribution

It introduces a theoretical model explaining the non-monotonic relaxation processes in Al-Y melts based on non-linear dynamics and heterogeneity effects.

Findings

Non-monotonic viscosity relaxation is linked to Ostwald ripening.

Relaxation kinetics are driven by non-linearity near the liquidus line.

Heterogeneity in Y concentration influences relaxation behavior.

Abstract

The slow non-monotonic relaxation processes, which have been recently fixed in Al-Y melts, are described theoretically. The theoretical description is based on the Cahn-Hilliard theory and functional methods of non-equilibrium dynamics. In terms of the suggested approach the reasons of this relaxation kinetics are non-linearity of the system near to the liquidus line, which sharply increases with Y concentration, and strong initial heterogeneity of the melt on the concentration of Y atoms. According to our analysis one can conclude that the non-monotonic temporal dependence of viscosity is caused by the Ostwald ripening processes in the rich in yttrium areas.