Two-level nanostructural states in metallic BCC-materials after high-pressure torsion in the Bridgman anvils A. N. Tyumentsev, I. A. Ditenberg, I. V. Smirnov [et al.]
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ArticleContent type: Текст Media type: электронный Subject(s): кручение под высоким давлением | электронная микроскопия | наноструктурные состояния | нанодиполи частичных дисклинаций | точечные дефекты | металлические материалы c ОЦК-решеткойGenre/Form: статьи в журналах Online resources: Click here to access online
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Russian physics journal Vol. 62, № 10. P. 1854-1864Abstract: The results of an electron-microscopy investigation of two-level nanostructural states (submicrocrystals,
measuring about 100 nm in size with the inner nanostructure and nanocrystal size about 10 nm, and crystal
lattice curvature of hundreds of deg/μm) formed in the specimens of unalloyed Ta and V and Mo–Re-based
alloys in the course of high-pressure torsion in the Bridgman anvils are generalized. A mechanism of their
formation is proposed – quasiviscous motion of nanodipoles of partial disclinations, which is controlled by the
flows of nonequilibrium point defects in the fields of high local pressure gradients. It is shown that the
microstructure evolution with the increasing deformation degree consists in an increase in the volume fraction
of a two-level nanostructural state, which results in a 3–4-fold increase in the microhardness of the deformed
specimens, its maximum values being in the range H ≈ (E/27–E/32). The principal physical factors and
conditions of formation of these states upon plastic deformation of submicro- and nanocrystals are discussed.
Библиогр.: 15 назв.
The results of an electron-microscopy investigation of two-level nanostructural states (submicrocrystals,
measuring about 100 nm in size with the inner nanostructure and nanocrystal size about 10 nm, and crystal
lattice curvature of hundreds of deg/μm) formed in the specimens of unalloyed Ta and V and Mo–Re-based
alloys in the course of high-pressure torsion in the Bridgman anvils are generalized. A mechanism of their
formation is proposed – quasiviscous motion of nanodipoles of partial disclinations, which is controlled by the
flows of nonequilibrium point defects in the fields of high local pressure gradients. It is shown that the
microstructure evolution with the increasing deformation degree consists in an increase in the volume fraction
of a two-level nanostructural state, which results in a 3–4-fold increase in the microhardness of the deformed
specimens, its maximum values being in the range H ≈ (E/27–E/32). The principal physical factors and
conditions of formation of these states upon plastic deformation of submicro- and nanocrystals are discussed.
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