Influence of a magnetic field on the precipitation behaviour of nano-scale cobalt particles in a copper matrix

The influence of a magnetic field on the microstructural evolution of nano-scale cobalt particles precipitated in a Cu–Co alloy during annealing at 973 K has been investigated using transmission electron microscopy (TEM). TEM observations revealed that an external field of ∼0.9 T accelerated precipitation and that the coherent–incoherent transition consequently occurred at an earlier time. The presence of the field, however, resulted in no significant change in the shape of the individual particles. A two-dimensional Monte Carlo simulation with the Ising spin model was also carried out to investigate the influence of an external magnetic field on the precipitation behaviour. These Monte Carlo simulations take both the chemical and magnetic interactions between solute atoms/clusters in the alloy into account, and successfully reproduced the qualitative features of the precipitation behaviour under a magnetic field seen in the experiments.

► We investigate the influence of external magnetic field on precipitation of ferromagnetic atoms in a Cu–Co alloy.
► TEM observations revealed that the application of the field accelerated the precipitation of the atoms, and consequently coherent–incoherent transition occurred earlier.
► The experimental results are compatible with the Curie temperature of cobalt and also implies that the precipitation behaviour occurred under the influence of magnetic interaction.
► The Monte-Carlo simulation qualitatively envisaged the microstructural evolution, taking both chemical and magnetic interactions into account.