National Research Nuclear University MEPhI, Moscow, Russia:

M. G. Isaenkova, Professor, Doctor Physics & Mathematics Sciences, e-mail: isamarg@mail.ru
Yu. A. Perlovich, Professor, Doctor of Physics & Mathematics Sciences

Ya. A. Babich, Postgraduate Student

All-Russian Scientific Research Institute of Aviation Materials, Moscow, Russia:
P. N. Medvedev, Sector Chief, Candidate of Physics & Mathematics Sciences

Titanium alloys, in spite of their low density, are characterized by high mechanical strength, corrosion resistance, creep resistance at elevated temperatures, heat resistance and manufacturability. A further increase in operational characteristics necessitates the development of new alloys. The presence in alloys of alpha-titanium, that is their low-temperature modification, characterizing by anisotropy of a crystalline hexagonal close-packed structure, predetermines the interest to predominant crystallographic orientations of grains in products. This work is devoted to the analysis of plastic deformation and heat treatment influence on the structure, crystallographic texture and mechanical properties of promising titanium alloys VT18U, VT41 and VT25U. The studied alloys belong to their different types: the first two ones are pseudo-α-alloys, and the last one — (α + β)-alloy. Sheet samples were subjected to hot rolling and subsequent heat treatment in order to identify the influence of technological parameters on the formation of phase state and crystallographic texture of the alloys. The structure and texture of materials were studied by metallographic and X-ray methods. The phase composition of alloys was determined and their texture was analyzed by constructing direct pole figures and restoring orientation distribution functions of grains. The measurement of mechanical properties was carried out using continuous indentation curves. As a result of the study, the basic regularities of crystallographic texture formation during hot rolling and subsequent phase transformations as applied to alloys of various types have been revealed. It was found that the main texture components of hot rolled sheets are {0001}±15–20^o ND-RD<112L>, {110}<100> and {110}<0001>, the ratios between which depend on the type of alloy. The mechanisms that determine the formation of texture during hot rolling were established. The limits of variation of the integral texture parameters for hotrolled titanium pseudo-α and (α + β)-alloys have been revealed, and the anisotropy coefficients of yield strengths for alloys with textures of different types have been calculated.
The research was conducted under financial support of the State Program for elevation of competitiveness in the National Research Nuclear University "MEPHI" (Agreement No. 02.a03.21.0005).

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