Phase equilibria of the Nd-B-Sm system were investigated through a combination of experiments and calculations of phase diagram. Based on the sub-binary phase diagrams, seven ternary alloys with different composition were designed and prepared using an electric arc melting furnace. Phase constituents of the Nd-B-Sm alloys annealed at 773 K, 873 K and in the as-cast state were investigated using electron probe microanalysis and X-ray powder diffraction. The results indicate that due to the similarity in atomic radii and electronegativity between Nd and Sm, the Nd-B and Sm-B compounds share identical crystal structures so that Nd₂B₅ and Sm₂B₅ form an infinite solid solution of (Nd,Sm)₂B₅, with no ternary compounds observed. Base on the phase equilibrium data obtained in this work and thermodynamic description on the binary systems reported in the literature, a set of self-consistent thermodynamic parameters is obtained by thermodynamic optimization of the Nd-B-Sm system using the CALPHAD method. The calculated isothermal sections at 773 K and 873 K, the liquidus projection, and the Scheil solidification path are in good agreement with the experimental data.
MEI Jiacheng
,
QIU Chengliang
,
LIU Shuhong
,
DU Yong
. Thermodynamic investigation of the Nb-B-Sm system[J]. Materials Science and Engineering of Powder Metallurgy, 2025
, 30(4)
: 289
-300
.
DOI: 10.19976/j.cnki.43-1448/TF.2025023
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