INVESTIGATION OF DIFFERENT DEFORMATION SCHEMES FOR OBTAINING FINE-GRAIN STRUCTURE OF CAST ALUMINUM ALLOY AK 7

Abstract

Abstract. The article investigated various schemes of deformation of the workpiece to improve the mechanical properties of the cast aluminum alloy AK 7. The most effective deformation schemes are spiral widening extrusion (SWE) and multi-angle pressing (MAP). Filling of a matrix most completely occurs at the SWE scheme, the degree of filling makes 90–95%. The depth of propagation of plastic deformation in the scheme of SWE is 6–9 mm. The results of numerical simulations correlate with the results obtained experimentally for the SWE matrix. It was experimentally determined that the increase in the accumulated shear deformation causes an increase in the values of microhardness. The magnitude of the accumulated deformation increases along the radial coordinate from the center to the edge of the workpiece. It was found that after the third transition in the central zone, the amount of accumulated deformation is approximately equal to the amount of deformation after the first pass in the edge zone. Mechanical properties, namely strength characteristics are increased. So after the first pass their values increase in relation to the source metal by 15%, after the second treatment by 20%, after the third by 25%.