Experimental investigation and thermodynamic re-assessment of the Mn–Nd binary system

Abstract

Fourteen Mn–Nd alloys were investigated experimentally by means of thermal analysis. The temperatures of the invariant reactions and liquidus in the Mn–Nd binary system were determined. Based on the experimental results obtained in the present work as well as the experimental data reported and the previous assessments in the literature, the Mn–Nd binary system was re-assessed thermodynamically using the CALPHAD method. The solution phases, including liquid, α-Mn, β-Mn, γ-Mn, δ-Mn, α-Nd and δ-Nd, are modeled by the substitutional solution model, and their excess Gibbs energies are expressed with the Redlich–Kister polynomial. The intermetallic compounds, Mn2Nd, Mn23Nd6 and Mn17Nd2, are treated as stoichiometric compounds. A set of self-consistent thermodynamic parameters obtained finally to describe the Gibbs energies of various phases in the Mn–Nd binary system can be used to reproduce well the reported phase equilibria and thermodynamic data.