Structural Turbulence of Plastic Flow and Ductile Fracture in Low-Alloy Steel under Lattice Curvature Conditions

The possibility of the structural turbulence of plastic flow and ductile fracture in low-carbon and low-alloy steel 09Mn2Si is shown by fracture toughness measurements and uniaxial tension of chevron-notched specimens at 20°C. The conditions for the structural turbulence of plastic deformation of solids are determined which provide high fracture toughness. The decisive functional role is played by the lattice curvature, the appearance of mesoscopic structural states in the lattice interstices at the nanoscale, the activation of self-consistent rotational motion in the hierarchy of mesoscopic structural levels, the presence of free volume, and the possibility of structural transformations at the nanoscale. A nonlinear theory of describing structural turbulence in a deformable solid is discussed.