Low-temperature solubility of copper in iron: experimental study using thermoelectric power, small angle X-ray scattering and tomographic atom probe

Measuring the solubility limit of copper in iron at temperature lower than 700 degrees C is problematic because copper diffusion is too slow in this temperature range. To overcome this difficulty, fine precipitation of copper is studied. The solubility limit of copper is measured after complete precipitation using two complementary techniques: thermoelectric power and small angle X-ray scattering. Values obtained are confirmed by tomographic atom probe and give results much higher than what is usually extrapolated from high-temperature experiments.