- Department - UNREGISTERED VERSION

STEEL GROUP

The group deals with studies of the electronic structure, short range atomic order and strengthening mechanisms in iron-based solid solutions aiming at research and development of a new class of engineering materials – high nitrogen steels.

Main scientific results:

(i) A correlation is found between the electronic structure (state density at the Fermi surface) and short-range atomic order in iron-based solid solutions. It is obtained that an increase in the metallic character of interatomic bonds assists short-range atomic ordering, whereas prevailing covalent bonds promote short-range decomposition (clustering).

(ii) It is shown that nitrogen increases the concentration of free electrons in austenitic steels and, based on this result, the beneficial nitrogen effects in steel are explained, such as: increased thermodynamic stability of solid solutions, high fracture toughness, high strengthening due to cold work and low temperatures, increased strengthening by grain boundaries etc. Main results are summarized in the monography V. Gavriljuk, H. Berns, High Nitrogen Steels, Springer, Berlin (1999).

(iii) It is found that combined alloying of steels with nitrogen+carbon is promising in terms of the increased thermodynamic stability of solid solutions, which suggests a unique possibility for design of cost-effective stainless austenitic steels.

 

International cooperation:

• Ruhr University, Bochum, Germany, Chair of materials technology (Prof. Dr. emeritus H. Berns, Prof. W. Theisen), Chair of materials properties (Prof. Dr. M. Pohl);
  

• Lille University of Sciences and Technologies, Lille, France, Laboratory of physical metallurgy and engineering materials (Prof. J. Foct);
  

• Albany Research Centre, Albany, Oregon, U.S.A. (Dr. J. Rawers).
  

Group Members:

Tyshchenko Andriy, team Leader
Mogylnyy Georgiy
Mogylna Iryna
Skoblik Oleksandr
Sirosh Vitaliy