STRENGTHENING OF COPPER DURING HIGH-SPEED DEFORMATION

One of the main research areas in recent decades in the field of materials science has been the search for possibilities to control the internal defective substructure of crystals to obtain the materials’ best strength and plastic properties. Strength here refers to the ability to withstand as large a load as possible without the onset of plastic defor-mation. High ductility implies the ability to withstand high plastic deformations be-fore localisation of plastic flow and the subsequent destruction of the metal begins. Studies of up-to-date micro-and nanostructured materials’ physical and mechanical properties are of great scientific and practical interest, especially, in recent years. This is because these materials demonstrate a range of unique physical and mechanical properties. Currently, many methods have been developed to produce micro-and nano-structured materials. One of the paths leading to grain refinement of metals and alloys is the use of various options of intense plastic deformation, as a result of which, de-pending on the degree of deformation, micro-or nanocrystalline structures are formed. One of these methods is the method of dynamic hardening under high-speed deforma-tion. This article shows that, during high-speed deformation in regions of a material with a submicron structure, grain-boundary slip dominates and the material is deformed in the superplasticity regime. In regions of the material with larger grain sizes, intragranular deformation dominates, accompanied by fragmentation and formation of a fine-grained structure with a submicron grain size. The transformation of structure from fine-grained to coarse-grained one occurs due to deformation-stimulated grain growth. Transformation of the structure from coarse-grained to fine-grained one occurs due to dynamic fragmentation. The transition from grain boundary sliding to in-tragranular deformation occurs at the optimal grain size necessary for dynamic recrys-tallization to occur.