FORMATION OF INVARIANT PLANE-STRAIN AND TENT-SHAPED SURFACE RELIEFS BY THE DIFFUSIONAL LEDGE MECHANISM

Electron channeling contrast and electron backscattering patterns (EBS Ps), generated in scanning electron microscopes (SEMs), were used to s tudy the question of whether tent-shaped surface reliefs associated wi th ferrite plates in Fe-0.07 pct and Fe-0.50 pct C low-alloy steels ar e single crystals or back-to-back pairs of plates. Although more than 50 ferrite plates were examined in detail, any misorientation containe d within them must have been < 1 deg. Additionally, no sightings of th e low-angle grain boundaries approximately bisecting ferrite plates ex pected on the back-to-back plates mechanism were ever made. The effort s of previous investigators to explain tent-shaped (and invariant plan e-strain) reliefs on the basis of diffusional ledgewise growth were fu rther extended.