About causes of slow relaxation of melted intermetallic alloys

• Published in: Calphad 2023-12, Vol.83, p.102615, Article 102615
• Main Authors: Lebedev, V.G., Shklyaev, K.Y., Menshikova, S.G., Vasin, M.G.
• Format: Article
• Language: English
• Subjects: Intermetallic alloys; Melts; Relaxation; Viscosity
• ISSN: 0364-5916; 1873-2984
• DOI: 10.1016/j.calphad.2023.102615

Ascertainment of the nature of the slow relaxation processes observed after melting in glass-forming eutectic melts is the subject of this work. We claim that the diffusion processes nonlinearity in heterogeneous melt with inclusions of refractory stoichiometry is the origin of this phenomenon. The cause for this nonlinearity is the thermodynamic instability similar to one taking place at spinodal decomposition, and indispensable condition is the initially non-homogeneous. For confirmation of our devotes, we consider the model of liquid solution of a binary system, which evolution described by the Cahn–Hilliard equation with combined Gibbs potential assuming the presence of remains after melting stoichiometric phase. Exemplified by the Al–Y and Al–Yb alloys, using Gibbs potentials from standard database we show that subject to initial heterogeneity in these systems the instability can develop leading to the slow relaxation processes, and determine the regions of this instability in the phase diagrams. •Explanation of the phenomenon of slow relaxation of eutectic melts is discussed.•We argue slow dynamics is result of non-linear diffusion in initially non-homogeneous sample.•The system evolution described by the Cahn-Hilliard equation with uphill diffusion.•The considered model allows indicate the slow melt relaxation areas on the phase diagram.