Modeling equations to predict the mixing behaviours of Al−Fe liquid alloy at different temperatures

Abstract

Redlich−Kister (R−K) polynomials have been associated with the extended regular associated solution model to predict and explain the thermodynamic properties and structural properties of Al−Fe liquid alloy at 1873 K, 1973 K, 2073 K and 2173 K; 1873 K being its melting temperature. The thermodynamic properties, such as free energy of mixing (G M ) and activities of free monomers (a Al and a Fe ) and structural properties, such as concentration fluctuation in long wave length limit (S CC (0)), chemical short range order parameter (α 1 ) and ratio of diffusion coefficients (D M /D id ) have been predicted at above stated temperatures. Renovated Butler model has been employed to predict the surface tension (σ) and surface segregation (x S ) of the alloy at stated temperatures with the help of thermodynamic properties. Theoretical findings prevail that the tendency towards compound formation of the liquid alloy decreases with increase in its temperature beyond melting temperature. Eventually, its surface tension decreases and there is gradual exchange of atoms between the surface and bulk regions to maintain equilibrium at elevated temperatures. The liquid alloy under investigation thus shows ideal behaviours at higher temperatures.

Mixing properties of Ni-Al liquid alloy at different temperatures

“…forming tendency at elevated temperatures. The theoretical findings of this work are in accordance with that of others [3,29,[37][38][39]40].…”

“…where the terms carry their meanings as mentioned earlier. Above Equation can also be written as [10,15,29] r ! r Os…”

“…The surface properties (surface tension (σ) and surface segregation (x and x p ))give the information about various mechanical properties such as, the catalytic activity of alloy catalysts and wettability. The surface properties of the preferred liquid alloy at 1873 K have been studied in the frame work of Renovated Butler model (RBM) [8,14,19,29,34]. The theoretical values of σ, x and x p are computed using Equation (17).…”

“…The theoretical values of σ, x and x p are computed using Equation (17). The surface partial excess free energy (∆G , ) required herein is computed using the expression ∆G , = β ∆G (24) where the values of ∆G are taken from Table 2 and the value of β is taken to be 0.8181 [8,14,19,29,34].…”

“…Eventually, we have extended STM by considering the linear temperature dependence of the interaction energy parameter to predict thermodynamic, structural and transport properties of the liquid alloy at temperatures 1873 K, 1973 K, 2073 K and 2173 K, 1873 K being the melting temperature of the system. Redlich-Kister (R-K) polynomials [28,29] have been associated with this approximation to determine the modeling parameters at different temperatures. The thermodynamic properties at different temperatures so computed have been correlated with RBM to predict the surface properties of the liquid alloy at above mentioned temperatures.…”