High-voltage electron diffraction measurement of the Debye temperatures of Cr, α-Fe and their disordered alloys

Abstract

The critical-voltage effect of high-voltage electron diffraction has been used to measure the X-ray Debye temperatures of Cr, α-Fe and their disordered alloys. The 220 critical voltages were measured at room and elevated temperatures for the pure metals and at room temperature for five intermediate compositions. The data for the pure metals were sufficient to determine both the Debye temperature and the deviation from the free-atom value of the atomic scattering factor at the first-order reflection position. The results agree with those of other workers. The scattering factor deviations were assumed to be the same in the alloys as in the pure metals, and this made it possible to determine the alloy Debye temperatures from a single room-temperature measurement of the critical voltage at each intermediate composition. The Debye temperatures are analyzed successfully in terms of a simple one-parameter theory, and are correlated with the alloy melting-point data through Lindemann's formula.