Structure and development of slip lines during plastic deformation of the intermetallic phases Fe3A1 and CuZn

The development and fine structure of slip lines on Fe3Al and β-CuZn single crystals has been investigated by video recording through a far distance optical microscope during compressive deformation and by scanning force microscopy (SFM) after deformation at room temperature up to temperatures beyond the yield stress peak. Different deformation modes, depending on temperature, are identified in Fe3A1 crystals and similarly found in β-CuZn. Homogeneous slip occurs at room temperature and is superposed on heterogeneous localized slip connected with stress serrations in a range of intermediate temperatures up to the yield stress peak, where the type of activated slip systems changes. These variations appear to be connected with the generation and motion of imperfect superdislocations at low and of perfect ones at intermediate temperatures, which, however, are gradually uncoupled with increasing temperature by an antiphase relaxation (local re-ordering) process, until beyond the peak dislocations of another slip system become more favourable.