Light Figures in Single Crystals of Iron-Aluminium Alloys

Abstract

Light figures produced by the three principal crystallographic planes {100}, {110} and {111} of etched single crystals of iron-aluminium alloys containing less than 6% Al were observed and their suitability for the orientation determination byteh light-figure method was examined. It was found that light figures revealed by etching for several minutes with 20% aqueous solution of ammonium persulphate were suitable to the orientation determination of iron-aluminium single crystals containing less than 4% Al,and those produced by etching for several minutes with saturated aqueous solution of ferric chloride were appropriate for cases of single crystals of pure iron and alloys containing more than 4% Al.