The Vacancy Cluster Tubes Formation and Metal Properties Changes After Dynamic Centrifugal Casting
American Journal of Modern Physics
Volume 7, Issue 6, November 2018, Pages: 194-202
Received: Oct. 23, 2018;
Accepted: Nov. 22, 2018;
Published: Mar. 22, 2019
Views 381 Downloads 68
Yuri Tarasov, National University of Science and Technology «MISIS», Moscow, Russia
Valery Kryachko, National University of Science and Technology «MISIS», Moscow, Russia
Viktor Novikov, National University of Science and Technology «MISIS», Moscow, Russia
Presents experimental results of Al and Pb metals crystallization carried out under high intensity plastic deformation (HIPD) [ε′ = (102–104) sec-1] reaching the level of so called «solid-liquid» state in the new type of centrifugal casting device at rotor speeds of up to 2000 rpm. Using the method of atomic force microscopy (AFM), vacancy cluster tubes (VCT) with average diameters of 39 nm for Al and 25 nm for Pb have been detected in the crystallized volume of Al and Pb metals. Physical model of the formation of a new substructure within the metals in the form of vacancy cluster tubes, received in the process of high-intensive plastic deformation (HIPD) during the process of mass crystallization of Al and Pb melts, and, also the changes in the mechanical, magnetic and superconducting properties of the above metals, which followed this process. When crystallizing Al and Pb under high-intensive plastic deformation (HIPD) of ε′ = (102–104) per second type, in high-speed centrifugal casting devices, specially selected modes of metal crystallization are being chosen and special conditions are being created to achieve the dimensional effect of dynamic (shift) re-crystallization. Shift deformation during centrifugal crystallization is caused primarily by a large incline of the temperature field from the periphery (relative to the cold wall of the rotor) to the molten central part of the rotor. The difference in the angular movement velocities of the already-frozen part of the metal (adjacent to the outer surface of the rotor wall) and the central part, where the metal still remains in the molten state, leads to a high-intensity deformation [ε′ = (102–104) sec-1] of the crystallized metal melt solidified phase. Since the grain sizes at the crystallized phase initially comprise around tens of nano-meters (approximately crystal nucleation size), it becomes possible to achieve the dimensional effect of the dynamic re-crystallization of a «nanocrystalline» solidified metal at high shift of strain velocities. The «non-equilibrium vacancies» formed this way condense into vacancy clusters, which are formed in the centrifugal force field in the form of vacancy-shaped cluster tubes stretched out to the center of rotation of the rotor. The process undergoes conditions that are considerably different from the «equilibrium» conditions as compared to the ordinary metal crystallization from the melt. Such processes can lead to the formation of highly ordered non-equilibrium states characteristic of non-equilibrium open systems.
The Vacancy Cluster Tubes Formation and Metal Properties Changes After Dynamic Centrifugal Casting, American Journal of Modern Physics.
Vol. 7, No. 6,
2018, pp. 194-202.
Novikov V. I., Lapovok V. N., Svirida S. V., Formation of non-equilibrium vacancies during re-crystallization of ultradispersed nickel powder. (Obrazovaniye neravnovesnykh vakansiy pri rekristallizatsii ul'tradispersnogo poroshka Nikelya), FTT, 1983, v. 25. No. 6, pp. 1846-1848.
Novikov. V. I., Gryaznov V. G., Trusov L. I., et al., Dimensional effect of recrystallization. Surface. (Razmernyy effekt rekristal-lizatsii, Poverkhnost'), Fizika, khimiya, mekhannika, 1986, v. 1, pp. 134-139.
Trusov L. I., Novikov V. I, Gryaznov V. G, et al., Properties and application of dispersed powders. (Svoystva i primeneniye dispersnykh poroshkov), K.: Naukova dumka, 1986, pp. v 98-114.
Trusov L. I., Novikov V. I, Gryaznov V. G., «Solid-Phase transformations caused by migrating borders», («Tverdofaznyye prevrashcheniya, initsiirovannyye migriruyushchimi granitsami»), Growth of crystals, Edited by Givargizov E. Ya. and Grinberg S. A, 1988, v. 17, Moscow, Science, pp. 69-86.
Novikov V. I., Lapovok V. N., Svirida S. V., et al.. «Formation of nonequilibrium vacancies in ultra-dispersed nickel powder under suppressive plastic flow» («Obrazovaniye neravnovesnykh vakansiy v ul'tradispersnom poroshke nikelya pri plasticheskom techenii pod davleniyem»), Physics of metals and metal science, 1984. v. 57, pp. 718-721.
Novikov V. I., Svirida S. V., Trusov L. I. «Activation of diffusion and phase transformations in ultradispersed media during plastic deformation” (“Aktivatsiya protsessov diffuzii i fazovykh prevrashcheniy v ul'tradispersnykh sredakh pri plasticheskoy deformatsii»), Metallophysics, 1984. v. 6, No. 3, pp. 114-115.
Utyashev F. Z. «Nano-structuring of metallic materials using the methods of intensive plastic deformation» («Nanostrukturirovaniye metallicheskikh materialov metodami intensivnoy plasticheskoy deformatsii», Physics and technology of high pressures, 2010, v. 20, No. 1, pp. 7-25.
Bridgman, P. W. Studies in large plastic flow and fracture, («Issledovaniye bol'shikh plasticheskikh deformatsiy i razryva»), Izdatelstvo inostrannoi literatury, Moscow, 1955.
Trusov L. I., Novikov V. I., Repin I. A., Kazilin E. E., Ganelin V. Ya., «Deformation of nickel with ultra-dispersed structure», (Deformatsiya Ni s ul'tradispersnoy strukturoy), Metallophysics, 1988, v. 10, No. 1, pp. 104-107.
Trusov L. I., Khvostantseva T. P.,. Solov’ev V. A., Mel’nikova V. A. «Low temperature stress relaxation of nano-crystalline nickel», («Nizkotemperaturnaya relaksatsiya napryazheniy nanokristallicheskogo nikelya»), Journal of Scientific Materials, 1995, Science, v. 30, No. 11, pp. 2956-2961.
Trusov L. I., Khvostantseva T. P., Solov’ev V. A., Mel’nikova V. A. “Stress relaxation following heating of nano-crystalline nickel, («Relaksatsiya napryazheniy posle nagrevaniya nanokristallicheskogo nikelya»), 1994, Nano-structured Materials, v. 4, No 7, pp. 803-813.
Novikov V. I., Khvostantsev L. G. et al., «Deceleration of re-crystallization of ultra-disperesed nickel powder at high hydrostatic pressure», («Zamedleniye rekristallizatsii ul'tradispersnogo poroshka nikelya pri vysokom gidrostaticheskom davlenii»), Metallophysics, 1986, v. 8 (2), pp. 111-113.
Novikov V. I., Ganelin V. Ya., Trusov L. I., et al. «Dilatation effect of in ultradispersed nickel polycrystalline during re-crystallization» («Effekt dilatatsii v ul'tradispersnom polikristalle nikelya pri rekristallizatsii»), Physics of solid body materials, 1986. v. 28, No. 4, pp. 1251-1254.
Novikov V. I., Valiev R. Z., Mulukov R. R., Mulukov H. Ya. Curie point and magnetization of nickel saturation with submicrigrain structure, Letters to the Journal of Technical Physics, v. 15, N 1, (1989), pp. 78-81.