Phase separation in a Ni–37 at.% Co–5% Nb alloy

Microstructural characterization has been performed on the decomposition in a Ni–37 at.% Co–5% Nb alloy during ageing at 500°C for times up to 501 h. Atom probe field ion and transmission electron microscopy data revealed a fine scale phase separation involving a Ni3Nb phase and a Co-enriched matrix. This phase separation explains the inability of a solid solution strengthening model which was developed to predict the yield stress for ternary Ni–M–Nb alloys.