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Producing thixotropic semi-solid A356 alloy: microstructure formation x forming behaviour

Wybrane pełne teksty z tego czasopisma
Identyfikatory
Warianty tytułu
Konferencja
12th International Scientific Conference CAM3S'2006, 27-30th November 2006, Gliwice-Zakopane
Języki publikacji
EN
Abstrakty
EN
Purpose: The work discuss the phenomena involved in the formation of the microstructure of semi-solid thixotropic alloy A356 produced by different techniques and the relation between microstructure and forming behaviour of the material. Design/methodology/approach: Thixotropic slurries of A356 alloy were produced from liquid and from solid conditions; in the first case either by stimulating nucleation rate or crystal multiplication during solid growth; in the second case by recrystallization and partial melting of deformed structures. Flow behaviour was analysed by viscosity measurements or by flow ability in forging operations. Findings: Results show that different production techniques activate different mechanisms, leading to distinct structure features in the semi-solid slurry, and, as consequence, in its forming characteristics. Techniques which promote formation of isolate globules of primary phase, like those involving nucleation stimulation and recrystallization, result in a semi-solid with better flowing behaviour. On the other hand, techniques based on crystal multiplication during growth lead to more interconnected globules in the slurry and poorer forming behaviour. Research limitations/implications: Semi-solid processing is suitable only for alloys with appropriate liquid fraction x temperature relation. Practical implications: the konowledge of the phenomena involved in the formation of thixotropic metallic slurries produced by different techniques, and their consequences in the material structure and flow behaviour, allow the decision of the adequate slurry production method for a specific application, in order to take the best advantage of the semi-solid technology. Originality/value: The analysis of the relation between production process x flow behaviour of semi-solid thixotropic A 356 is original.
Rocznik
Strony
19--26
Opis fizyczny
Bibliogr. 15 poz., fot., rys.
Twórcy
autor
autor
autor
autor
  • Faculty of Mechanical Engineering, State University of Campinas, SP, CEP 13083-970, Brazil, helena@fem.unicamp.br
Bibliografia
  • [1] G.P. Pires, M.H. Robert, R. Arrieux, Studies on drawing of the aluminium A5052 alloy in the thixocast condition, J. of Materials Processing Technology, v. 15, 2004, 596 - 603.
  • [2] M. Rovira, M.H. Robert, Thixoforming of Al-Cu Alloys, J. of Materials Processing Technology, v. 92-93, 1999, 42-49.
  • [3] M. Margarido, M.H. Robert, Influence of Thermo-mechanical Treatments on Rheocast Slurries by Partial Melting, J. of Materials Processing Technology, v. 133. 2003, 149-157.
  • [4] M. Adamiak, M.H. Robert, Preliminary Studies on the Suitability of Rheocast Al Alloys for Deep Drawing, J. Materials Processing Technology , 2001, v. 109, 168-173.
  • [5] E.J. Zoqui, M.H. Robert, Structural modifications in rheocast Al-Cu alloys and implications on mechanical properties, J. of Materials Processing Tecnhnology, v. 78, 1998, 198-203.
  • [6] M.C. Flemings, Behaviour of Metal Alloys in Semisolid State, Metallurgical Transactions A. v. 22a, 1991, 957-981.
  • [7] H. Kaufmann, H. Wabusseg, PJ. Uggowitzer, Casting of Wrought Alloys by New Rheocasting, 6th Int. Conf. Semi-solid Processing of Alloys and Composites, Italy, 2000,457-463.
  • [8] M. Garat, Aluminium Semi-solid Processing: from the Billet to the Finished part, 5 th Int. Conf. on Semi-solid Processing of Alloys and Composites, Colorado, USA, 1998, 199-214.
  • [9] E.J. Zoqui, M.H. Robert, Contribution to the Study of Mechanisms Involved in the Formation of Rheocast Structures, J. of Materials Processing Technology, v. 109, 2001, 215-219.
  • [10] M. Margarido, M.H. Robert, Production of Rheocast Slurries by Partial Melting through Alternative Treatments. J. of The Brazilian Society of Mechanical Sciences and Engineering, v. 25, 2003, 207-214.
  • [11] E.J. Zoqui, M. Paes, M.H. Robert, Effect of macrostructure and microstructure on the viscosity of the A356 alloy in the semi-solid state, J. of Materials Processing Technology v. 153154, 2004, 300-306.
  • [12] A. Ohno, T. Motegi, H. Soda, Origin of the Equiaxed Crystals in Castings, Trans. Iron and Steel Institute of Japan, v.18, 1971, 11-14.
  • [13] V. Laxmanan, M.C. Flemings, Deformation of Semi-Solid Sn-15wt%Pb , Metall. Transl., v.11A, 1980, 1927-1937.
  • [14] J.D. Hunt, K.A. Jackson, Formation of Equiaxial Crystals ir Castings, Journal of Applied Physics, v.37, 1966, 254-259.
  • [15] J. Gurland, The Influence of Composition and Microstructure on the Strength of Cast Aluminium-Silicon Alloys, Z.Metallkde, v.61, N°8, 1970, 606-612.
Typ dokumentu
Bibliografia
Identyfikator YADDA
bwmeta1.element.baztech-article-BOS5-0018-0001
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