Direct Observation of Lattice Defects in Cold-worked High Manganese Steels by Means of Electron Microscopy

Thin foils have been made by electrolytic polishing from bulk specimens of cold-worked high manganese steel. They have been observed by electron microscopy with the object of studying lattice defects formed by cold-working. From the micrographs and the selected area electron diffraction patterns obtained it is concluded that on {111} planes of the austenite matrix very thin (<100Å) plates of a hexagonal close-packed phase ( ε ) are formed, which correspond to the origins of strain markings formerly found on the etched surface by using the replica, and that ordinary stacking faults as found in 18–8 stainless steels are also present.