Growth of High‐Purity Iron Single Crystals

Abstract Single crystals of spectrographic pure iron from Johnson and Matthey have been prepared by strain‐anneal method both from as‐received rods and from those refined by floating‐zone melting in dry hydrogen. Attempts to grow single crystals by both dynamical and statical annealing of critically strained specimens were successful. Usually the crystals were 4 mm in diameter and 35–60mm long with random crystallographic orientations. In the present paper the influence of grain size and homogeneity of polycrystalline matrix and of impurity content on the growth of single crystals and on the size, number and kind of included grains are reported. It resulted that single crystals can be grown successfully from high‐purity iron without adding any impurity. Single crystals prepared from as‐received iron rods contained a number of included grains distributed statistically which occupied 0.5–1 p.c. of the total volume of the single crystal. In single crystals grown from zone‐refined iron no included grains occurred.