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MATERIALS SCIENCE
ArticleName Structure and properties of prospective Be – Si-based casting alloy for thermal-dimensional-stable details
DOI 10.17580/tsm.2016.07.11
ArticleAuthor Gvozdkov I. A., Belikov B. A., Sizenev V. S., Bryantsev P. Yu.
ArticleAuthorData

JSC “Kompozit”, Korolev, Russia:

I. A. Gvozdkov, Leading Engineer of the Institute of Beryllium, e-mail: gvozdick@inbox.ru
B. A. Belikov, Deputy Executive Officer of the Institute of Beryllium
V. S. Sizenev, Executive Officer of the Institute of Beryllium

 

National University of Science and Technology MISiS, Moscow, Russia:
P. Yu. Bryantsev, Assistant Professor, e-mail: p_bryant@rambler.ru

Abstract

Requirements to materials for space-based optoelectronic devices (OED) are reviewed. There are shown the prospects of using beryllium-silicium alloys to develop thermal dimensional stable casting alloy (with composition close to the eutectic point providing the thermal dimensional agreement of parts in OED). The experimental alloys were made by investment casting, with beryllium content from 34 to 44% by weight. The microstructure was investigated by optical and scanning electron microscopy, and hardness was determined at room temperature and the linear coefficient of thermal expansion (CTE) in the temperature range from 20 to 500 oC. Eutectic alloy microstructure consists of eutectic and primary beryllium dendrites. The eutectic phase has both a columnar and plate structure. Primary dendrites are surrounded by pure silicon, formed by degenerate eutectic. Pores are detected in alloy microstructure. Pore distribution is diffuse in nature, and the shape is mainly spherical, which indicates the gas-shrinkage porosity. The presence of primary silicon crystals in hypereutectic alloy structure leads to embrittlement. The measured hardness of the alloys is between 450 and 550 HV, which are characterized as intractable alloys. The coefficient of linear thermal expansion of experimental alloys is reduced to 50% in the temperature range of 20–500 oC, compared with technical sintered beryllium. Weak CTE dependence on temperature was detected: the value of the CTE of the experimental alloys increases by only 12% in the temperature range of 100–500 oC, while the CTE of beryllium is changed to 48%. Reduced CTE of alloys provides thermal-dimensional agreement to optical glasses used in the OED.

keywords Beryllium, silicon, casting alloy, investment casting, microstructure, thermal expansion coefficient, hardness
References

1. Campbell F. C. Manufacturing technology for aerospace structural materials. Oxford : Elsevier, 2006. 600 p.
2. Solntsev Yu. P., Pryakhin E. I., Piraynen V. Yu. Spetsialnye materialy v mashinostroenii (Special materials in mechanical engineering). Saint Petersburg : Khimizdat, 2004. 640 p.
3. Schuster G., Pokross C. High-performance Be – Al casting alloys. Light metals. San Francisco : TMS, 2013. pp. 259–264.
4. Okamoto H. Be – Si (Beryllium-Silicon). Journal of Phase Equilibria and Diffusion. 2009. Vol. 30, No. 1. p. 115.
5. Gvozdkov I. A. Vybor sistemy legirovaniya liteynykh berillievykh splavov (Choice of the system of alloying of casting beryllium alloys). Sbornik materialov “FNM-2014” (Collection of materials “FNM-2014”). Moscow : A. Baikov Institute of Metallurgy and Materials Science, Russian Academy of Sciences, 2012. 476 p.
6. Walsh K. A. Beryllium chemistry and processing. Materials Park : ASM International, 2009. 575 p.
7. Papirov I. I. Struktura i svoystva splavov berilliya : spravochnik (Structure and properties of beryllium alloys : references). Moscow : Energoizdat, 1981. 322 p.
8. Kolachev B. A., Elagin V. I., Livanov V. A. Metallovedenie i termicheskaya obrabotka metallov i splavov : uchebnik dlya vuzov (Metal science and thermal treatment of metals and alloys : tutorial for universities). Third edition. Moscow : MISiS, 1999. 614 p.
9. Kaskov V. S. Berilliy – konstruktsionnyy material dlya mnogorazovoy kosmicheskoy sistemy (Beryllium — a structural material for the reusable spaceship system). Aviatsionnye materialy i tekhnologii = Aviation Materials and Technologies. 2013. No. S1. pp. 19–29.
10. Zhu Pan, Yong Du, Baiyun Huang, Honghui Xu, Yong Liu, Hailin Chen, Wei Xiong. Experimental study of the Be – Si phase diagram. Journal of Material Science. 2006. No. 41. pp. 2525–2528.
11. Zhu Pan, Yong Du, Baiyun Huang. Experimental investigation and thermodynamic calculation in the Al – Be – Si ternary system. Zeitschrift für Metallkunde. 2005. Bd. 96, No. 11. S. 1301–1307.
12. GOST 2169–69. Kremniy tekhnicheskiy. Tekhnicheskie usloviya (State Standard 2169–69. Silicon technical. Specifications). Introduced: 1970–07–01. (in Russian)
13. R. W. Cahn, P. Haasen. Fizicheskoe metallovedenie. Tom 2. Fazovye prevrashcheniya v metallakh i splavakh i splavy s osobymi fizicheskimi svoystvami (Physical Metallurgy. Volume 2. Phase transformations in metals and alloys and special physical properties alloys). Moscow : Metallurgiya, 1987. 624 p.

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