The diffusivity and solubility of copper in ferromagnetic iron at lower temperatures studied by atom probe tomography

The diffusion coefficient and the solubility limit of copper in ferromagnetic iron were directly measured using atom probe tomography at lower temperatures than in previous studies. Cu–Fe diffusion couples were annealed at temperatures from 550 to 750 °C. The diffusion coefficient was determined to be D = 0.48 exp(−Q/kBT) m s−1 (Q = 3.22 eV), which, below 650 °C, is about 1.3 times higher than the extrapolation from a previous study considering the magnetic effect. The measured Cu solubility limit is in good agreement with literature.