Experimental investigation, thermodynamic optimization and prediction of glass-forming ability of the Nb-Ni-Sn ternary system

At 800, 700 and 600°C, the phase equilibria of the Nb-Ni-Sn system were investigated through phases analysis of twenty-four designed equilibrated alloys. By analyzing the experimental results, it can be found that the addition of Ni can improve the stability of the Nb₆Sn₅ phase to be stable at below 700°C. In addition, the ternary compound NbNi₂Sn was confirmed with the composition of about Nb_24.5-23.2Ni_49.8-53.5Sn_25.6-23.3 (in at.%). The sublattice model Nb₁Ni₂(Ni, Sn)₁ was used to describe the NbNi₂Sn compound. The thermodynamic parameters of the Nb-Ni-Sn system were assessed by means of the CALPHAD methodology. Finally, the driving force of each phase in supercooled liquid phase was calculated by using the evaluation results, and the predicted composition region with high glass forming ability is very consistent with the literature data.