Field-ion microscopy of ferrous martensite

Abstract

Fine structures of as-quenched martensite in an Fe-0.8% C-0.4% Mn steel were investigated using field-ion microscopy techniques. Both untwinned and twinned martensite regions were detected. Differences in image contrast and regularity of net plane edges were found in the hydrogen-ion images of pure iron and untwinned martensite. It is proposed that in the twinned martensite images the twins appear as bright bands while dark bands represent the intersection of twin boundaries with the specimen surface. The twins were found to have a {112} orientation and a width of 25–100 Å.