Abstract
Grain formation during solidification of magnesium and Mg-Al alloys has been studied with a focus on grain refinement mechanisms, solute and particle effects. The variation in grain size with increased aluminium content in hypoeutectic Mg-Al alloys showed a continuous decrease in grain size up to 5 wt% Al, and a stabilisation at higher Al contents (above 5 wt%). Strontium additions to both low- and high-aluminium content magnesium alloys showed that Sr had a significant grain refining effect in low-aluminium containing alloys. However, strontium had a negligible effect on grain size in the Mg-9Al alloy. Additions of Zr, Si, or Ca to pure magnesium produced significant grain refinement, probably because these elements have high growth restriction effects during solidification. An attempt was made to identify the grain refinement effect of particles added directly to the melt that are considered to be powerful nucleants in Al based alloys (TiC) and in Mg based alloys (AlN, Al4C3). Most of these particles produced grain refinement, probably because of enhanced nucleation due to the small lattice disregistry between their crystal structures and that of magnesium. However, it is not clear whether the grain refining mechanism of the effective particles was catalysis of primary crystal nucleation or simply restriction of crystal growth during solidification.
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References
I.J. Polmear, Light Alloys: Metallurgy of the Light Metals, (London, UK: Arnold, 1995) 197–209.
J. Campbell, “Castings”, (Oxford, UK: Butterworth- Heinemarm, 1997) 261–262.
M.A. Easton, “Grain Refinement Mechanisms in Aluminium and its Alloys and the Effect of Grain Refinement on Castability,” (Ph.D. thesis, The University of Queensland, 1999), 57–85.
W. Kurz, and D.L. Fisher, Fundamentals of solidification, (Aedermannsdorf, Switzerland: Trans Tech Publications, 1989) 21–42.
J.E.C. Hutt, D.H. StJohn, and A.K. Dahle, “Equiaxed Solidification of Al-Si Alloys,” Materials Science and Technology, 15 (1999) 495–500.
Y.C. Lee, A.K. Dahle, and D.H. StJohn, “The Effect of Grain Refinement and Silicon Content on Grain Formation in Hypoeutectic Al-Si Alloys,” Materials Science and Engineering A A 259 (1999), 43–52.
M.A. Easton, and D.H. StJohn, “Grain Refinement of Aluminium Alloys II. Conformation of, and a Mechanism for the Solute Paradism,” Metallurgical and Materials Transactions A 30A, (1999), 1625–1633.
A.K. Dahle, and L. Amberg, “On the Assumption of Additive Effect of Solute Elements in Dendrite Growth,” Materials Science and Engineering A, A225, (1997) 38–46.
J.E. Gruzleski, and C.A. Altravci, “Low porosity, Fine Grain Sized Strontium Treated Magnesium Alloy Castings,” United States Patent No 5,143,564 (1992)
F. Emley, Principles of Magnesium Technology (Oxford, UK: Pergamon, 1966), 260.
L.A. Davis, and L.W. Eastwood, “Grain Refinement of Magnesium Casting Alloys,” Trans AFS, 53 (1945) 352–362.
N. Tiner, “Superheating of Magnesium Alloys,” Metals Technology, 12 (1) (1945) 1–19.
E.L, Glasson and E.F Emley, “Heterogeneous Nucleation in the Solidification of Aluminium and Magnesium Alloys,” The Solidification of Metals, (London, UK: The Iron and Steel Institute, 1967) 1–9.
V.B. Kurfman,, “Nucleation Catalysis by Carbon Addition to Magnesium Alloys,” Trans AIME, 221 (1961) 540–546.
D.O. Karlsen, D. Oymo, H. Westengen, P.M.D Pinfold, and S.I. Stromhaug, “Development of Grain Refiner for Aluminium Containing Magnesium Alloys,” Light metals Processing and Applications, Canadian Inistitute of Mining, Metallurgy and Petrolium Eds, (Canadian Inistitute of Mining, Metallurgy and Petroleum, Quebec, Canada, 1993) 397–408.
G. Nussbaum, P. Bridot, T.J. Warner, J. Charbonnier, and G. Regazzoni, “New Mg-Al Based Alloys with Improved Casting and Corrosion Properties,” Magnesium alloys and their applications, B.L. Mordike, and Hehmann Eds., (Oberursel, Germany: DGM informationsefesellshaft, 1992) 351–368.
C.E. Nelson, “Grain Size Behaviour in Magnesium Casting Alloys,” Trans AFS, 56 (1948), 1–23.
R.T. Wood, “Grain Refinement of Magnesium Castings,” The Foundryman, (1953) 98–99, 256–261.
A. Luo, and M.O. Pekguleryuz, “Solidification Processing and Microstructure of Cast Magnesium MMCs,” Trans AFS, 102 (1994) 313–320.
A. Luo, “Heterogeneous Nucleation and Grain Refinement in Cast Mg(AZ91)/SiC Metal Matrix Composite,” Canadian Metallurgical Ouarterly, 35 (4) (1996) 375–383.
K. Sato and M.C. Flemings, “Grain Refinement of Al- 4.5 Cu Alloy by Adding an Al-30TiC Master Alloy,” Metallurgical and Materials Transactions A 29A (1998) 1707–1710.
D.G. McCartney, “Grain Refining of Aluminium and Its Alloys using Inoculants,” International Materials Reviews 34 (1989) 247–260.
A. Luo, “Development of Matrix Grain Structure During the Solidification of a Mg(AZ91)/SiC Composite,” Scripta Metallurgica et Materialia., 31 (1994) 1253–1258.
E.A. Brandes, ed., Smithells Metals Reference Book 6th ED (London, UK: Butterworth, 1983), 6–1∼6–35.
P.K. Rohatgi, “interfacial Phenomenon in Cast Metal- Ceramic Particle Composites,” Interfaces in Metal- Matrix Composites (Warrendale, USA: The Metallurgical Soctety/AIME, (1986), 185–202.
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Lee, Y.C., Dahle, A.K., StJohn, D.H. (2016). Grain Refinement of Magnesium. In: Mathaudhu, S.N., Luo, A.A., Neelameggham, N.R., Nyberg, E.A., Sillekens, W.H. (eds) Essential Readings in Magnesium Technology. Springer, Cham. https://doi.org/10.1007/978-3-319-48099-2_41
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DOI: https://doi.org/10.1007/978-3-319-48099-2_41
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