Effect of Strain Aging on Stages of Plastic Strain and Tensile Fracture of Specimens of Steel 08G2B. Part I. Yield Plateau and the Stage of Strain Hardening

Mechanisms of Luders deformation in tensile tests of specimens of steel 08G2B with ultrafine ferrite-bainite structure are studied by the method of digital image correlation. The fields of displacements of eyy and exy and their distribution over the length of a specimen are determined. Two kinds of Luders deformation differing in the behavior of the Chernov–Luders bands are detected. The results of the measurement of microhardness in Chernov–Luders bands and of the EBSD analysis are used to determine the interrelation between the strain aging effect and the variation of the characteristics of strength (σy , σr ) and ductility (δpl , δu , δ, n ) at tension.