Papers by Author: Sergei Ya. Betsofen

Abstract: Methods of complex X-ray and metallographic analyses have been used to investigate the influence of texture, thin structure and grain boundaries of coiled low-alloyed steel for gas-and-oil pipeline tubes after hot rolling on its mechanical properties. Finish rolling temperature changes in a wide range (ТFR = 8900С-5300С). Specifics of steel structure formation under conditions of dynamic (controlled rolling) and static (high-and-low temperature rolling) recrystallization have been found.

Abstract: The paper considers the structure evolution during annealing of submicrocrystalline (SMC) titanium with a mean grain size of 0.2 µm, processed by severe plastic “abc” deformation. Electron microscopic studies have revealed that the microstructure of the SMC titanium is heterogeneous and of a mixed type. One can observe a high density of dislocations, grains, subgrains, elements of a banded structure and areas comprising coarse (up to 1-2µm) and fine (up to 0.1µm) grains. The grain boundary misorientation spectrum is presented by low angle and high angle boundaries of random and special types. Three stages of annealing of SMC titanium have been revealed. The second stage is connected with the intense SMC grain growth and the value of activation energy of grain growth at this stage is twice less than the value of activation energy of grain boundary diffusion in titanium. The latter is caused by acceleration of diffusion processes at SMC grain boundaries having an atom-disordered structure. The texture evolution with annealing temperature is characterized by weakening of predominantly basal texture in the as-received SMC state and strengthening of a prismatic component. The weakening of the basal component is connected with the growth of SMC grains first of all, as well as the increase of the volume fraction of special boundaries.

Abstract: The X-ray rocking curve method (RCM) was used to characterize microstructure and texture of Al and alloys: Al-Mg (AMg6) and Al-Mg-Li (1420), Al- Mg-Sc (1570) after cold rolling to a 8-70 % reduction in thickness, and then annealing at 300-5500C. The fractions of recrystallized grains with {111}, {100}, {113} and {110} orientation in the sheet plane and its distribution on the sizes was measured by a RCM. For these alloys a grains with orientation of {111} and {100} grow much faster than grains {113} and particularly {110}. In an alloy 1420 at 300-4000C continuous recrystallization takes place with fine grains and weakening rolling texture