Values of the Debye temperature 0 for iron-manganese solid-solution alloys have been determined from X-ray diffracted intensity measurements of powder specimens at ambient temperatures of 310, 239, and 98°K. Corrections to 0 were made with respect to the temperature-dependence of Θ, temperature diffuse scattering, dispersion, volume expansion of the alloy, and the temperature gradient through the specimen. The variation of Θ with temperature has been found to be approximately linear, the value of Θ decreasing 3 % between 98 and SICTK. for a nominal Fe–4%Mn alloy.
Increasing the concentration of manganese in an iron-manganese solid-solution alloy decreases Θ in qualitative agreement with Lindemann's equation. The values of Θ for other s olid-solution alloys computed using Lindemann's equation also agree with reported experimental values of Θ. The Debye temperature of a nominal Fe-3%Mn alloy annealed for 2 hr at 300, 600, and 700°C has not been found to maximize at 600°C as has been reported by Il'ina et al. On the contrary, Θ decreases with increasing annealing temperature until, in the range 600 to 700°C, it reaches its true value; and at these temperatures the powder was found to be fully annealed.