Substructural and phase transformations during plastic deformations of materials obtained by intensive deformation

The paper presents the results of electron microscopy investigations of the defect structure evolution and the phase transformation of ultra fine-grained (UFG) Cu and Cu-Al-O alloy. The UFG Cu was prepared using the equal-channel angular (ECA) pressing method. The Cu-Al-O alloy was synthesized by mechanical milling and subsequent high temperature pressing. The initial grain size of the materials was 200 nm. The grain and dislocation structures were investigated qualitatively and quantitavely. In the Cu alloy, deformation twinning was revealed to occur in coarse grains together with slip deformation. The evolution of grain and dislocation micro structure in the presence or absence of solid solution and of dispersion hardening is analyzed, and differences are assessed.