Sintering Atmosphere Effects on the Densification of Al-SiC Compacts

Authors: Tadeusz Pieczonka, Jan Kazior

Abstract:

The influence of SiC powder addition on densification of Al-SiC compacts during sintering in different atmospheres was investigated. It was performed in a dilatometer in flowing nitrogen, nitrogen/hydrogen (95/5 by volume) and argon. Fine, F500 grade of SiC powder was used. Mixtures containing 10 and 30 vol.% of SiC reinforcement were prepared in a Turbula mixer. Green compacts of about 82% of theoretical density were made of each mixture. For comparison, compacts made of pure aluminum powder were also investigated. It was shown that nitrogen is the best sintering atmosphere because only in this atmosphere did shrinkage take place. Its amount is lowered by ceramic powder addition, i.e. the more SiC the less densification occurs. Additionally, the formation of clusters, enhanced in compacts containing 30 vol.% SiC, is also responsible for limiting the shrinkage. Microstructural examinations of sintered composites revealed that sintering of compacts occurs in the presence of the liquid phase exclusively in nitrogen.

Keywords: Al-SiC composites, densification, sintering atmosphere.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1091920

References:

[1] G.B. Schaffer, S.H. Huo "On Development of Sintered 7xxx Series Aluminium Alloys”, Powder Metallurgy, vol. 42, 1999, 3, 219-225.
[2] F.V. Beaumont "Aluminium P/M: Past, Present and Future”, Int. J. Powder Metallurgy, vol. 36, 2000, 6, 41-43.
[3] Ch. Lall, W. Heath "P/M Aluminium Structural Parts – Manufacturing and Metallurgical Fundamentals”, Int. J. Powder Metallurgy, vol. 36, 2000, 6, 45-50.
[4] W.H., Jr. Hunt "New Directions in Aluminium – Based P/M Materials for Automotive Applications”, Int. J. Powder Metallurgy, vol. 36, 2000, 6, 51-60.
[5] G.B. Schaffer, D. Apelian "Aluminum Powder Metallurgy: Process, Properties and Design Solutions”, Booklet published by The Aluminum Association, 2000.
[6] H. Weber "Sintering of New PM Aluminium Alloys: New Sintering Furnaces Concept for Stringent Sintering Process Conditions”, Proc. of EURO PM‘2001, European Congress and Exhibition on Powder Metallurgy, vol. 2, pp. 171-176.
[7] W.A.G. McPhee, J. Drennan, G.B. Schaffer "Iron and Microstructural Development During Sintering of Al-Cu-Mg Alloys”, PM2TEC 2001, Advances in Powder Metallurgy & Particulate Materials - 2001, Proc. of the 2001 Int. Conf. on Powder Metallurgy & Particulate Materials, New Orleans 2001, pp. 9-139 – 9-147.
[8] N. Myers, R.M. German "Sintering of Aluminium Flakes for Lightweight Applications”, PM2TEC 2001, Advances in Powder Metallurgy & Particulate Materials - 2001, Proc. of the 2001 Int. Conf. on Powder Metallurgy & Particulate Materials, New Orleans 2001, pp. 9-192 – 9-198.
[9] H.C. Neubing, J Gradl, H. Danninger "Sintering and Microstructure of Al-Si P/M Components”, PM2TEC 2002, Advances in Powder Metallurgy & Particulate Materials - 2002, Proc. of the 2002 Int. Conf. on Powder Metallurgy & Particulate Materials, Orlando 2002, pp. 13-128 – 13-138.
[10] H. Weber, P. Delarbre, M. Krehl, K. Link "Sintering of High Performance PM Aluminium Alloys”, PM2TEC 2002, Advances in Powder Metallurgy & Particulate Materials - 2002, Proc. of the 2002 Int. Conf. on Powder Metallurgy & Particulate Materials, Orlando 2002, pp. 13-150 – 13-156.
[11] K.C. Ramesh, R. Sagar "Fabrication of Metal – Matrix Composite Automotive Parts”, Int. J. Adv. Manuf. Technol., vol. 15, 1999, pp. 114-118.
[12] R.R. Phillips "High Strength Aluminum Metal Matrix Composites”, PM2TEC 2000, Advances in Powder Metallurgy & Particulate Materials - 2000, Proc. of the 2000 Int. Conf. on Powder Metallurgy & Particulate Materials, New York 2000, pp. 12-63 – 12 69.
[13] S. Yamagata, M. Imamura, Y. Hirose, T. Sugiyama, O. Suwata, K. Kamitake, M. Omachi, Y. Abe, A. Fukui "P/M Al-SiC Composite Through Sintering Process for Heat Spreader in Semiconductor Devices”, ", Proc. Powder Metallurgy World Congress and Exhibition PM‘2000, Kyoto, Eds. K. Kosuge, H. Nagai, vol. 2, 1174-1177.
[14] K.. Tomolya "Production and Investigation of Aluminum-base and SiC Particles Reinforced Composites”, Thesis, University of Miskolc, 2001.
[15] Z. Gácsi, T. Pieczonka, J. Kovács, Á. Kovács, M. Szigethy, G. Buza "Characterization of Microstructure of Sintered and Laser Remelted Composites”, in "Materials Development and Processing,-Bulk Amorphous Materials, Undercooling and Powder Metallurgy”, Ed. L. Schultz, D. M. Herlach, J. V. Wood, Vol. 8. (2000) p. 375.
[16] Z. Gácsi, J. Kovács, T. Pieczonka "Investigation of Sintered and Laser Surface Remelted Al-SiC Composites”, Surface & Coatings Technology. Vol. 151-152 (2002) p. 320.
[17] Z. Gacsi, J. Kovacs, T. Pieczonka "Particle Arrangement Characterization by the Pair Correlation Function”, Powder Metallurgy Progress. Journal of Science and Technology of Particle Materials, vol. 3, 2003, 30-38.
[18] T. Pieczonka, Th. Schubert, S. Baunack, B. Kieback "Dimensional behaviour of aluminium sintered in different atmospheres”, Materials Science and Engineering A, vol. 478, 2008, 251-256.
[19] T. Pieczonka, S.C. Mitchell, A.S. Wronski, J. Kazior, M. Hebda „Postulation of a mechanism of nitrogen sintering of aluminium", PM2TEC 2008, Advances in Powder Metallurgy & Particulate Materials - 2008, Proc. of the 2008 World Congress and Exhibition on Powder Metallurgy & Particulate Materials, vol. 5, 25-40.
[20] G.B. Schaffer, B.J. Hall "The Influence of the Atmosphere on the Sintering of Aluminum”, Metallurgical and Materials Transactions A, vol. 33A, 2002, 3279-3284.
[21] T. Pieczonka, Z. Gácsi, F. Kretz, J. Kovács "Sintering Behavior of Al-SiC Powder Mixtures Controlled by Dilatometry”, Proc. PM2004 World Congress & Exhibition, Vienna, 2004, Vol. 2, 95-100.
[22] Th. Schubert, T. Pieczonka, S. Baunack, B. Kieback "The Influence of the Atmosphere and Impurities on the Sintering Behaviour of Aluminum”, Proc. EURO PM2005 Congress & Exhibition, Prague 2005, vol. 1, 3-8.
[23] T. Pieczonka „Powder Metallurgy Processing of Aluminium ”, in „Polish Metallurgy 2006-2010 in Time of the Worldwide Crisis", Committee of Metallurgy of the Polish Academy of Sciences, Ed. E. Swiątkowski, vol. 1, 37-57.