Phase Equilibria and Amorphous Phase Formation in the Ni–Nb–P Ternary Alloy System

Abstract

Liquidus projections in the Ni-rich corner of the Ni–Nb–P ternary system have been studied through the analysis of as-cast microstructures. A peritectic reaction involving Ni₉Nb₂P and Ni₂NbP is proposed: L+Ni₉Nb₂P→Ni₂NbP. The slopes of liquidus surface boundaries between Ni solid solution (Ni_ss), Ni₃P, Ni₉Nb₂P and Ni₂NbP along with two invariant reactions are proposed: L+Ni_ss→Ni₃P+Ni₉Nb₂P and L→Ni₃P+Ni₉Nb₂P+Ni₂NbP. A ternary amorphous alloy with a large undercooled region before crystallization (ΔT_x=15°C) is developed demonstrating the importance of phase equilibria in designing the alloy with high glass forming ability.