Determination of Debye temperature of α-iron by X-ray diffraction

The Debye temperature of α-iron at 298°K has been determined from Geiger-counter measurements of the Bragg intensities from a polycrystalline sample (using Mo Kα) and theoretical atomic scattering factors. The value obtained (⪹D = 398 ± 9°K) is somewhat less than the average value (418 ± 4°K) calculated from all the available diffraction results. The diffraction values are significantly lower than those (467°K) derived from elastic-constants. Intensity measurements from annealed and ground samples placed experimentally on the same scale showed that plastic deformation did not reduce the integrated intensities of the reflections. This result provides further evidence for the rejection of the ‘frozen-in thermal motion' picture of plastic deformation.