Accumulation of Defects under Plastic Deformation of Polycrystalline Copper-Based Alloys

Abstract

The paper presents the experimental investigation of the role of the size factor in the formation of the defect structure of metallic materials. The objects of study were polycrystalline FCC Cu–Al and Cu–Mn solid solutions with average grain sizes of 10–240 µm. The dislocation structure of foil samples subjected to various deformations at room temperature was studied by TEM. We measured the scalar dislocation density (ρ), the density of geometrically necessary dislocations (GND) (ρ_g), the density of statistically stored dislocations (SSD) (ρ_s), the curvature-torsion of the crystal lattice (χ), and some other parameters. The effect of the grain size of the dislocation substructure on its parameters has been quantitatively studied. The sources of curvature-torsion χ of the crystal lattice were determined from electron microscopic images. We measured χ in the alloys under study from different sources and its change with distance (x) from the source for alloys with fixed grain size and degree of deformation. The change in the average value of curvature-torsion from all sources with the degree of deformation is considered.