INFLUENCE OF SHEAR ROLLING ON THE FORMATION OF STRUCTURE AND MECHANICAL PROPERTIES OF A DISPERSION-STRENGTHENED ALUMINUM ALLOY

Abstract

The paper presents the results of the study of shear rolling influence on the formation of the structure and properties of metal from a dispersion-strengthened aluminum alloy. The difference in microhardness, grain structure parameters, fine structure (microstress level, mosaic block size and dislocation density) in samples obtained by shear rolling (ShR) and standard rolling (StR) on a smooth barrel at different deformation degrees was studied. It was found that with increasing deformation degree, the microhardness of the material increases approximately equally, however, when reaching a logarithmic deformation degree е ≥ 2 in samples obtained by ShR technology, weakening processes begin. The drop in microhardness at this degree of deformation may be associated with the start of in-situ recovery or recrystallization during deformation. The grain shape characteristics differ significantly, namely, in samples obtained by the ShR technology, the вшааукутсу of grain size in the direction along and across the rolling is less than in the StR samples, which can also be explained by the activation of the recovery and recrystallization processes under the influence of shear deformations. The study of the current structure by the X-ray structural analysis method showed that the size of the mosaic blocks changes according to the same laws. A comparison of the magnitude of microstresses allows us to draw the following conclusions: for the corresponding treatments, the microstress in the cross section is less than in the longitudinal, by approximately 30% for STtR and by 50% for ShR; after StR treatment, the magnitude of microstresses is greater than after rolling with shear by 30% in the cross section and by 4% in the longitudinal. The obtained results allow us to state that when implementing the ShR technology, when the logarithmic deformation degree e ≥ 2 is reached, the development of the directional recrystallization process begins during deformation.