The role of phase transitions in the evolution of dispersion particles in chromium bronzes upon the equal channel angular pressing

I.A. Faizov1, G.I. Raab1, S.N. Faizova1, N.G. Zaripov1, D.A. Aksenov2, D.A. Aksenov2
1Ufa State Aviation Technical University, Ufa, K. Marks, 12, Russia
2Institute of Molecule and Crystal Physics Ufa Research Center of RAS, 71 pr. Oktyabrya, Ufa, 450000, Russia
Abstract
Samples of a diluted Cu-Cr-Zr alloy were processed with a combination of severe plastic deformation (SPD) methods. The average sizes and distribution density of particles with different chemical compositions undergo an evolution that indicates that phase transformations occur even during the cold deformation. A decomposition of the solid solution due to the deformation-induced acceleration of diffusion contributes to this evolution, but the whole complex of observations cannot be explained only by this phenomenon and implies the presence of the deformation-induced dissolution of particles. A possible mechanism of the dissolution linking this process to a mechanical fragmentation of the particles upon the SPD is discussed. A dependence of the dissolution efficiency on the composition of the particles was noted. A conclusion about the simultaneously occurring kinetically opposite phase transitions is also confirmed by an observation of changes in the lattice constant of copper that are non-monotonous versus the accumulated strain. The crystalline structure refinement upon the SPD proceeds through self-organization of dislocation pile-ups into grain boundaries what implies an influence of the particles –obstacles to dislocation motion – on the structural transformations. Thus, there exists an interdependence between strain mechanisms and phase transitions such as the second phase particles precipitation and their dissolution in the copper matrix that influences the structure refinement, the dispersion particles distribution and, consequently, the strength and other properties of the material. This influence may be especially complicated in alloys that like the one under study have a second phase consisted of particles of many different compositions.
Received: 28 March 2016   Revised: 09 April 2016   Accepted: 10 April 2016
Views: 102   Downloads: 27
References
1.
V. M. Segal. Mater. Sci. Eng. 1995. V. A197. P. 157 – 164.
2.
V. M. Segal, V. I. Reznikov, V. I. Kopylov etc. Processing of structure formation in metals. Minsk: Since and Technology, 1994. 231 p. (in Russian) [Сегал В. М., Резников В. И., Копылов В. И. и др. Процессы структурообразования металлов. Минск: Наука и техника, 1994. 231 с.]
3.
R. Z. Valiev, I. V. Aleksandrov. Nanostructured materials obtained by severe plastic deformation. M.: Logos, 2000. 272 p. (in Russian) [Валиев Р. З., Александров И. В. Наноструктурные материалы полученные интенсивной пластической деформацией. М.: Логос, 2000. 272 с.]
4.
R. A. Andrievskiy, A. M. Glezer. Uspekhi fi zicheskikh nauk, 2009, T. 179, № 4, p. 337 – 358. DOI: 10.3367 / UFNr.0179.200904a.0337 (in Russian) [Андриевский Р. А., Глезер А. М. Прочность наноструктур. УФН, 2009, Т. 179, c. 337 – 358]
5.
S. Faizova, G. Raab, D. Aksenov, N. Zaripov, I. Faizov / The physical aspects of the formation of high-state precipitation hardened alloys under severe plastic deformation by torsion // Physical Mesomechanics. № 4. 2015 [С. Н. Фаизова (4), Г. И. Рааб (19), Д. А. Аксенов (0), И. А. Фаизов (0) / Физические аспекты формирования высокопрочного состояния дисперсионно-упрочняемых сплавов при интенсивной пластической деформации кручением // «Физическая мезомеханика», № 4, 2015]
6.
A. Vinogradov, V. Patlan, Y. Suzuki, K. Kitagawa, V. Kopylov. Acta Materialia. 2002. V.50, P.1639 – 1651. DOI: 10.1016 / S1359–6454 (01) 00437 – 2
7.
A. Vinogradov, T. Ishida ets. Acta Materialia. 2005. V.53. P.2181 – 2192. DOI: 10.1016 / j.actamat.2005.01.046
8.
S. N. Faizova, R. Z. Valiev, N. V. Mazhitova, G. I. Raab. The kinetics of non-equilibrium solid solution of Cu-Cr during intensive plastic deformation by torsion. Electronic journal «Phase transitions, ordered States and new materials». 4. 2010. URL: http://ptosnm.ru / ru / issue / 2010 / 4 / 49 / publication / 533 (in Russian) [Фаизова С. Н., Валиев Р. З., Мажитова Н. В., Рааб Г. И.. Неравновеснвя кинетика твердого раствора системы Cu-Cr при интенсивной пластической деформации кручением. Электронный журнал «Фазовые переходы, упорядоченные состояния и новые материалы». 4. 2010. URL: http://ptosnm.ru / ru / issue / 2010 / 4 / 49 / publication / 533]
9.
V. V. Sagaradze, V. A. Shabashov, T. M. Lapina, et al. Low-temperature strain-induced dissolution of intermetallic Ni3Al (Ti, Si, Zr) phases in Fe — Ni alloys with fcc lattice. Fiz. Met. Metalloved., 78 (6), 1994, 49 – 61. (in Russian) [В. В. Сагарадзе, В. А. Шабашов, Т. М. Лапина. Низкотемпературное деформационное растворение интерметаллидных фаз Ni3Al (Ti, Si, Zr) в Fe-Ni сплавах с ГЦК решёткой. ФММ. — 1994. — Т.78, N 6. — С.49 – 61]
10.
V. V. Sagaradze, S. V. Morozov, V. A. Shabashov, L. N. Romashev, I. R. Kuznetsov. Dissolution of spherical and lamellar intermetallics in Fe-Ni-Ti austenitic alloys during cold plastic deformation. Fiz. Met. Metalloved. 66 (2), 1988, P. 328 – 338. (in Russian) [В. В. Сагарадзе, С. В. Морозов, В. А. Шабашов, Л. Н. Ромашёв, Р. И. Кузнецов. Растворение сферических и пластинчатых интерметаллидов в Fe-Ni-Ti аустенитных сплавах при холодной пластической деформации. ФММ. — 1988. — Т.66, N 2. — С.328 – 338.]
11.
V. A. Shabashov Nonequilibrium diffusion phase transformations and nanostructuring in intense cold deformation. Materials science. 2008. N 3 (55). P. 169 – 179 (in Russian) [Шабашов, В. А. Неравновесные диффузионные фазовые превращения и наноструктурирование при интенсивной холодной деформации. Вопросы материаловедения. — 2008. — N 3 (55). — С.169 – 179]
12.
V. V. Sagaradze, Diffusion transformation in steels due to cold deformation, Metallovedenie i Termicheskaya Obrabotka Metallov, No. 9, pp. 19 – 27, September, 2008. (in Russian) [В. В. Сагарадзе Диффузионные превращения с сталях при холодной деформации, МиТОМ, 2008, № 9, с.19 – 27.]
13.
Y. R. Kolobov, R. Z. Valiev. Grain-boundary diffusion and properties of nanostructure materials // Novosibirsk: Nauka, 2001, p. 232. (in Russian) [Колобов Ю. Р., Валиев Р. З и др. Зернограничная диффузия и свойства наноструктурных материалов. Новосибирск: Наука, 2001, с. 232.]