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METAL PROCESSING
ArticleName The features of phase composition and microstructure of piston alloys AlSi12CuMgNi and AlSi12Cu2MgNi
ArticleAuthor Samoshina M. E., Belov N. A., Savchenko S. V.
ArticleAuthorData

Engineering Center «Innovation Casting Technologies and Materials», Moscow, MISiS, Russia:

M. E. Samoshina, Senior Researcher

 

Chair of Casting Processes Technology, MISiS, Moscow, Russia:

N. A. Belov, Professor, e-mail: nikolay-belov@yandex.ru

 

Vsevolozhsk plant of aluminium alloys, Vsevolozhsk, Russia:

S. V. Savchenko, Deputy Chief Executive Officer of Production

Abstract

Piston alloys are a special group of aluminum-silicon alloys. A distinctive feature of their composition is high silicon content (10 to 27%). The main application of these alloys is the production of pistons for a variety of engines, compressors, etc. Piston alloys have a complicated phase composition, which requires the analysis of multicomponent phase diagrams. The systematic analysis of phase composition for piston alloys AlSi12CuMgNi and AlSi12Cu2MgNi based on the thermodynamic calculations of multicomponent phase diagrams in the Thermocalc software was performed. To analyze the effect of composition and temperature the isothermal and polythermal sections were constructed. It is shown that the presence of manganese and higher concentration of copper in the alloy AlSi12Cu2MgNi affects the phase composition. In the alloy AlSi12CuMgNi eutectic (Al)+(Si) is primary crystallizing, but in the alloy AlSi12Cu2MgNi the primary crystals are the particles of Al15(FeMn)3Si2 phase. The effect of crystallization rate and cooling rate after annealing on the microstructure and phase composition of piston alloys was studied. To simulate different cooling conditions the initial industrial ingot was melted and then casted at 800 оС into a graphite mold (cooling rate is about 10 K/s) or cooled in the crucible with the same temperature in air (cooling rate is about 1 K/s). Heating for quenching was performed at 500, 520 and 540 оC. The heating time was 6 h. The specimens were quenched after annealing in water. The agreement between the results of phase compositiondetermining by microstructure analysis and by the method of thermodynamic calculations is found. In the alloy AlSi12Cu2MgNi structure after annealing at 540 оC identified obvious signs of overburning, while they were not found in structure of the alloy AlSi12CuMgNi. It can be explained by lower solidus temperature of the alloy AlSi12Cu2MgNi due to higher content of copper

keywords Piston alloys, phase composition, phase diagrams, microstructure, heat treatment, crystallization rate
References

1. Zolotorevskiy V. S., Belov N. A. Metallovedenie liteynykh aluminievykh splavov (Physical metallurgy of casting aluminium alloys). Moscow : MISiS, 2005. 376 p.
2. Polmear I. J. Light Metals: From Traditional Alloys to Nanocrystals : 4th ed. Amsterdam : Elsevier, 2005. 421 p.
3. Mondolfo L. F. Struktura i svoystva splavov : perevod s angliyskogo (Structure and properties of alloys : translastion from English). Moscow : Metallurgiya, 1979. 640 p.
4. Alyuminiy : svoystva i fizicheskoe metallovedenie : spravochnik (Aluminium : properties of physical metallurgy : reference book). U. U. Anthony, F. R. Ellyott, M. D. Boll. Under the editorship of G. E. Hatch. Translated from English. Moscow : Metallurgiya, 1989. 324 p.
5. Hernandez R. C., Sokolowski J. H. Thermal analysis and microscopical characterization of Al–Si hypereutectic alloys. Journal of Alloys and Compounds. 2006. Vol. 419. pp. 180–190.
6. Zeren M. The effect heat-treatment on aluminum-based piston alloys. Materials and design. 2007. Vol. 28. pp. 2511–2517.
7. Taghiabadi R., Ghasemi H. M., Shabestari S. G. Effect of iron-rich intermetallics on the sliding wear behavior of Al–Si alloys. Materials Science and Engineering A. 2008. Vol. 490. pp. 162–167.
8. Li R. X., Li R. D., He L. Z., Li C. X., Gruan H. R., Hu Z. Q. Age-hardening behavior of cast Al–Si base alloy. Materials Letters. 2004. Vol. 58. pp. 2096–2101.
9. Belov N. A., Eskin D. G., Aksenov A. A. Multicomponent Phase Diagrams : Applications for Commercial Aluminum Alloys. Amsterdam : Elsevier, 2005. 414 p.
10. Belov N. A., Eskin D. G., and Avxentieva N. N. Constituent Phase Diagrams of the Al–Cu–Fe–Mg–Ni–Si System and their Application to the Analysis of Aliminium Piston Alloys, Acta Materialia. 2005. Vol. 53. pp. 4709–4722.
11. Belov N. A., Savchenko S. V., Belov V. D. Atlas mikrostruktur promyshlennykh siluminov (Atlas of industrial alpax microstructure). Moscow : MISiS, 2009. 204 p.
12. GOST 1583–93. Splavy alyuminievye liteynye (State Standart 1583–93. Aluminium casting alloys). Moscow : Publishing house of standards, 1993.
13. Siluminy : atlas struktur i fraktogramm : spravochnik (Silumines : atlas of structures and fracture patterns : reference book). Under the editorship of Yu. N. Taran, V. S. Zolotorevskiy. Moscow : MISiS, 1996. 175 p.

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