Mechanism of localized-deformation macroband development in submicrocrystalline armco-iron

The mechanism of localized-plastic deformation macroband development under tension of the submicrocrystalline armco-iron specimens with banded fragmented substructure was investigated. It was found that plastic flow of submicrocrystalline armco-iron is localized near the grips and realizes by self-consistent macroband propagation similar to phase wave. Macrobands develop according to either a dipole or a cross configuration. The fracture of the specimens occurs due to the development of the main crack within macrobands along the direction of maximum tangential or normal stresses. Inside the macrobands the banded fragmented substructure formed under preliminary equichannel angular pressing changes into a netlike dislocation substructure. Substantial work-softening of the material occurs due to appreciable macrolocalization of plastic flow.