Etch‐Pit Observations Concerning Twins in Iron and Iron Alloys

Etch‐pit procedures may be used to gain qualitative information about processes involving twins in samples deformed to strains of the order of 10%; a visual representation of the local strain fields may be obtained together with evidence which may be interpreted in favor of the emissary dislocation model for twin growth. The etch‐pit procedure reveals about 10% of the dislocations thought to be present and indicates local stresses around twin/twin or twin/grain boundary intersections at least 20% higher than the over‐all stresses at distances of about 10 μ or five times the width of the twins.