Abstract
During plastic flow, simultaneously with the formation of junction disclinations, which are linear mesodefects, planar shear mesodefects appear at the grain boundaries and facets of the boundaries, the stress fields from which can significantly affect the orientation and characteristics of a microcrack formed at the junction. The configurational force method is used to analyze the conditions for the existence of stable cracks in the elastic field of a combined mesodefect, which is a superposition of a wedge disclinations dipole and a planar mesodefect. In the configuration space of the parameters of the system under consideration (the strength of the disclinations dipole and the planar mesodefect, the length of the mesodefect, and the angle that specifies the orientation of the crack), the ranges of parameter values are determined at which such cracks can appear. The dependences of the critical strength of the disclination dipole and the length of the nuclear crack arising in the vicinity of the negative disclination of the dipole on the length of the mesodefect are calculated for different values of the strength of the planar mesodefect. It was assumed that the opening of the crack occurs in the direction coinciding with the orientation at which the length of the nuclear crack at fixed values of the strength of the disclinations dipole, the strength of the planar mesodefect and the length of the mesodefect is minimal, and, therefore, the energy for its creation is minimal. It is generally concluded that shear-type mesodefects can significantly facilitate the initiation of microcracks in the vicinity of junction disclinations. In the range of parameter values that allow the existence of stable cracks, the length of the nuclear crack decreases with increasing strength of the planar mesodefect. It is shown that the critical length of the crack is tenths of the length of the disclination dipole.
References (12)
1. V. V. Rybin. Large plastic deformations and destruction of metals. Moscow, Metallurgy (1986) 224 p. (in Russian) [В. В. Рыбин. Большие пластические деформации и разрушение металлов. Москва, Металлургия (1986) 224 с.].
2. V. V. Rybin, V. N. Perevezentsev, Y. V. Svirina. Phys. Metals Metallogr. 118 (12), 1171 (2017).
Crossref3. V. V. Rybin, I. M. Zhukovsky. Phys. Solid State. 20 (6), 1829 (1978). (in Russian) [В. В. Рыбин, И. М. Жуковский. ФТТ. 20 (6), 1829 (1978).].
4. M. S. Wu, K. Zhou, A. A. Nazarov. Phys. Rev. B. 76 (13), 134105 (2007).
Crossref5. G. F. Sarafanov, V. N. Perevezentsev. Def. and Fract. of Mat. 2, 2 (2016). (in Russian) [Г. Ф. Сарафанов, В. Н. Перевезенцев. Деформация и разрушения материалов. 2, 2 (2016).].
6. M. S. Wu. Int. J. Plast. 100, 142 (2018).
Crossref7. T. Wang, J. Luo, Z. Xiao, J. Chen. Eur. J. Mech. A. 28 (4), 688 (2009).
Crossref8. V. Rybin, V. Perevezentsev, S. Kirikov. Phys. Metals Metallogr. 119 (5), 421 (2018).
Crossref9. V. L. Indenbom. Phys. Solid State. 3, 2071 (1961). (in Russian) [В. Л. Инденбом. ФТТ. 3, 2071 (1961).].
10. G. F. Sarafanov, V. N. Perevezentsev, V. V. Rybin. Fundamentals of the kinetic theory of the formation of disoriented structures during plastic deformation of metals. N. Novgorod, Litera (2011) 359 p. (in Russian) [Г. Ф. Сарафанов, В. Н. Перевезенцев, В. В. Рыбин. Основы кинетической теории формирования разориентированных структур при пластической деформации металлов. Н. Новгород, Литера (2011) 359 с.].
11. V. A. Likhachev, R. Ю. Khayrov. Introduction to the theory of disclinations. Leningrad, Leningrad University (1975) 183 p. (in Russian) [В. А. Лихачев, Р. Ю. Хайров. Введение в теорию дисклинаций. Ленинград, Ленинградский университет (1975) 183 с.].
12. V. V. Rybin, A. N. Vergazov, Yu. F. Titovets. Surface. 6, 134 (1986). (in Russian) [В. В. Рыбин, А. Н. Вергазов, Ю. Ф. Титовец. Поверхность. 6, 134 (1986).].