Polygonization

One of the types of polygonization is the dynamic polygonization that occurs during the hot processing of metals ( rolling , forging , etc.). At the first stage, the formation of the so-called. "Cellular" structure. Then, when ordering the dislocation walls, the formation of small-angle subboundaries occurs. As a result, the cellular structure turns into elongated subgrains. Further development of dynamic polygonization leads to the appearance of subboundaries perpendicular to those obtained at the previous stage. This leads to the formation of equiaxial subgrains. Further post-deformation exposure or temperature increase leads to recrystallization , that is, an increase in the misorientation angle between subgrains and their transformation into grains. In steels with vanadium, the precipitation of vanadium carbide VC at these boundaries blocks them, and subsequent recrystallization does not occur. A similar effect occurs when doping with niobium , chromium and other carbide and nitride forming elements. The mechanism of dynamic polygonization is the main one in thermomechanical processing of metals.

A great contribution to the study of polygonization mechanisms was made by the MISiS scientific school under the guidance of Professor M. L. Bernshtein . At present, the thermomechanical processing laboratory created by M. L. Bernshtein regularly holds Bernshtein readings on thermomechanical processing of metal materials, devoted to the problems of hot deformation of metals, including problems of polygonization.

Bernstein Readings on the Thermomechanical Processing of Metallic Materials

1. M. L. Bernstein. The strength of steel. M., "Metallurgy", 1974
2. M. L. Bernstein. The structure of deformed metals. M., "Metallurgy", 1977
3. M. L. Bernstein, V. A. Zaimovsky, L. M. Kaputkina . Thermomechanical processing of steel. M., "Metallurgy", 1983
4. M. L. Bernstein. Hot deformation diagrams, structure and properties of steel. M., "Metallurgy", 1989