The precise determination of the lattice parameter of α-iron and some of its alloys

A method, applicable using either the transmission Kossel or divergent X-ray beam techniques, is described in detail. Calculations have shown that its greatest sensitivity corresponds to the lattice parameter region slightly less than that of pure α-iron. Its most useful applications should thus be for the study of α-iron alloys containing Be, Co or Si, elements which decrease the parameter of α-iron, as well as the low-temperature thermal expansion coefficients of other α-iron alloys. Its sensitivity still seems sufficient, however, for the parameter determination at room temperature of interstitial alloys such as Fe–C and Fe–N. This method is not applicable to those α-iron alloys containing appreciable concentrations of Ti, V, Cr or Mn.