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Proceedings of the National Academy of Sciences of Belarus. Physical-technical series

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Influence of decomposition of oversatured liquid solutions on the structure and microhardness of quickly curing alloys of the Pb–Sn system

https://doi.org/10.29235/1561-8358-2019-64-4-391-397

Abstract

The results of studies of the structure and microhardness of foil alloys of the lead–tin system obtained by high-speed cooling from the liquid phase are presented. The foil sample had the following dimensions: length – up to 10 cm, width – up to 1 cm, and thickness – 30–80 microns. Melt cooling rate was not less than 105 K/s. A rapidly cooled foil is chara cterized by a dispersed structure. The size of the discharge of tin and lead does not exceed 5 μm. The specific surface of the interfacial boundaries achieve 1.7 μm–1. Due to supercooling, a microcrystalline structure forms in the foil. The average lengths of chords of random secants on lead and tin grain sections in the Pb–73 at.% Sn alloy foil are 0.8 and 1.8 μm respectively. The texture of (111) lead and (100) tin is formed in the foil of alloys of the lead – tin system under certain conditions. The formation of the structure of lead alloys containing from 20 to 95 at.% tin is due to the occurrence of spinodal decomposition of a supersaturated liquid solution, and, in other alloys, due to decay by the mechanism of formation and growth of nuclei of crystalline phases. The stratification of the liquid solution leads to the formation of areas enriched in lead and tin, which contribute to the formation of crystallization centers that are equally distributed in the volume of the foil. The microhardness of the foil alloys, whose compositions are close to eutectic, is less than the microhardness of massive alloys of the same composition, which is associated with the softening effect of grain boundaries and interphase boundaries. Exposure of these alloys at room temperature causes an increase in microhardness due to a decrease in slippage at the boundaries. The decomposition of supersaturated solid solutions of Pb–5 at.% Sn and Sn–1 at.% Pb alloys leads to a decrease in microhardness due to the weakening of the effect of the solid solution hardening mechanism. The results of the study can be used to create fusible solders, bearing alloys, alloys for cable sheaths with improved physicochemical properties.

About the Authors

V. G. Shepelevich
Belarusian State University
Russian Federation

Vasily G. Shepelevich – D. Sc. (Physics and Mathe matics), Professor, Professor of the Department “Physics of a Solid Body”.

4, Nezavisimosti Ave., 220030, Minsk



O. N. Belaya
Belarusian State Medical University
Russian Federation

Olga N. Belaya – Ph. D. (Physics and Mathematics), Associate Professor, Associate Professor of the Department “Medical and Biological Physics”.

93, Dzerzhinsky Ave., 220116, Minsk



E. Yu. Neumerzhytskaya
Belarusian National Technical University
Russian Federation

Elena Yu. Neumerzhytskaya – Ph. D. (Physics and Mathe matics), Associate Professor, Associate Professor of the Department of Technical Physics.

65, Nezavisimosti Ave., 220013, Minsk



References

1. Mal’cev M. V. Metallography of non-ferrous industrial metals and alloys. Moscow, Metallurgiya Publ., 1970. 364 p. (in Russian).

2. Andryushchenko M. Lead-free soldering. Alternative alloys. Elektronika: nauka, tekhnika, biznes = Electronics: science, technology, business, 2004, no 5, pp. 47–49 (in Russian).

3. Ochoa F., Williams J. J., Chawla N. The effects of cooling rate on microstructure and mechanical behavior of Sn-3.5Ag solder. JOM, 2003, vol. 55, iss. 6, pp. 56–60. https://doi.org/10.1007/s11837-003-0142-7

4. Miao Hui-Wei, Duh Jenq-Gong. Thermal cycling test in Sn-Bi and Sn-Bi-Cu solder joints. Journal of Materials Science – Materials in Electronics, 2000, vol. 11, iss. 8, pp. 609–618. https://doi.org/10.1023/A:1008928729212

5. Vasil'ev V. A., Mitin B. S., Pashkov I. N., Serov N. M., Skuridin A. A., Lukin A. A., Yakovlev V. B.. High-speed solidification of melts: theory, technology and materials. Moscow, SP Intermet Inzhiniring Publ., 1998. 400 р. (in Russian).

6. Miroshnichenko I. S. Quenching from a liquid state. Moscow, Metallurgiya Publ., 1982. 192 p. (in Russian).

7. Shepelevich V. G. Rapidly hardened low-melting alloys. Minsk, Belarusian State University, 2015. 192 p. (in Russian).

8. Rusakov A. A. Metallography of metals. Moscow, Atomizdat Publ., 1977. 400 p. (in Russian).

9. Saltykov S. A. Stereometric metallography. Moscow, Metallurgiya Publ., 1976. 272 p. (in Russian).

10. Shepelevich V. G., Belaya O. N., Goltsev M. V. Microstructure and mechanical properties of a tin-lead eutectic alloy produced by high-speed solidification. Gusev O. K. et al. (eds.). Priborostroyeniye-2018: materialy Mezhdunarodnoi nauchno-tekhnicheskoi konferentsii, Minsk, 14–16 noyabrya 2018 g. [Instrumentation-2018: Materials of the International Scientific and Technical Conference, Minsk, November 14–16, 2018]. Minsk, Belarusian National Technical University, 2018, pp. 262–264 (in Russian).

11. Shepelevich V. G., Belaya O. N., Neumerzhitskaya E. Y. Microstructure of fast-cooled from a melt of tin-lead system alloys. Popechits V. I. et al. (eds.). Prikladnyye problemy optiki, informatiki, radiofiziki i fiziki kondensirovannogo sostoyaniya: Mezhdunarodnoi nauchno-tekhnicheskoi konferentsii, Minsk, 11–12 maya 2017 g. [Applied problems of optics, computer science, radiophysics and condensed matter physics: Materials of the International Scientific and Technical Conference, Minsk, May 11–12, 2017]. Minsk, A. N. Sevchenko Institute of Applied Physical Problems of Belarusian State University, 2017, pp. 293–295 (in Russian).

12. Pashkov I. N., Pikunov M. V., Tavolzhanskii S. A., Pashkov A. I. Development of processes for the preparation and use of alloys of solders in a dispersed state with a microcrystalline or amorphous structure. Metallurgist, 2010, vol. 54, no. 5-6, pp. 358-361. https://doi.org/10.1007/s11015-010-9303-4

13. Tsigler. G. Extreme principles of thermodynamically irreversible processes and continuum mechanics. Moscow, Mir Publ., 1966. 136 p. (in Russian).

14. Glazov V. M., Pavlova L. M Chemical thermodynamics and phase equilibria. Moscow, Metallurgiya Publ., 1988. 560 p. (in Russian).


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ISSN 1561-8358 (Print)
ISSN 2524-244X (Online)