Role of Bi and Ca Additions in Controlling the Microstructure of Sr-Modified 319 Alloys


Article Preview

The role of bismuth (50 to 9000 ppm) and calcium (50 to 200 ppm) additions on the microstructural characteristics in Sr-modified 319 alloys (with/without 0.4 wt% Mg addition) were investigated using optical and electron microscopy, and image analysis. It was found that the modification effect of Sr continuously diminished with Bi addition up to ~3000 ppm Bi; further Bi addition led to the modification of the Si particles due to the presence of Bi. In the Ca-containing alloys, a coarse eutectic Si structure resulted with Ca additions of 50 ppm, due to the formation of Alx(Ca,Sr)Siy compounds. Increased Ca additions (up to 200 ppm) did not alter the Si particle size. The Alx(Ca,Sr)Siy phase particles appeared in rod-like form in the Sr-modified alloys and in plate-like form in the 319+0.4 wt% Mg alloys. MgO, Al2O3, and AlP particles appear to act as nucleants for the precipitation of the plate-like Alx(Ca,Sr)Siy phase.



Materials Science Forum (Volumes 519-521)

Edited by:

W.J. Poole, M.A. Wells and D.J. Lloyd




S. El Hadad et al., "Role of Bi and Ca Additions in Controlling the Microstructure of Sr-Modified 319 Alloys", Materials Science Forum, Vols. 519-521, pp. 1257-1264, 2006

Online since:

July 2006




[1] J.E. Hatch (Ed. ), Aluminum: Properties and Physical Metallurgy (American Society for Metals, Metals Park, Ohio, 1984).

[2] H. Toshihiro, K. Toshiro, N. Mitsuo and S. Yuichi, Keikinzoku Gakkai Taikai Koen Gaiyo Vol. 84 (1993), p.133.

[3] T. Kobayashi, H. J. Kim and M. Niinomi, , Mater. Sci. Technol. Vol. 13 (1997), p.497.

[4] N.P. Pillai and T.R. Anantharaman, Trans. Metall. Soc. of AIME Vol. 242 (1968), p. (2025).

[5] D.E.J. Talbot and C.E. Ransley, Metall. Trans. A Vol. 8A (1977), p.1149.

[6] J.I. Cho and C.R. Loper, AFS Trans. Vol. 108 (2000), p.359.

[7] A.V. Kurdyumov and S.V. Inkin, Liteino Proizvodstvo Vol. 6 (1986), p.56.

[8] A.V. Kurdyumov and S.V. Inkin Liteinoe Proizvodstvo Vol. 7 (1988), p.17.

[9] D. Kube, F. Josef, S. Siegered and A. Achen, Giesserei Vol. 85 (1998), p.38.

[10] Kawahara, Hiroshi, Awano Yoji, Journal of Japan Foundry Engineering Society Vol. 69 (1997), p.556.

[11] C.R. Loper and J.I. Cho, AFS Trans. Vol. 180 (2000), p.585.

[12] M. Nagao, K. Kunii and K. Oosumi, Keikinzoku Gakkan Taikan Koen Gaiyo Vol. 89 (1995), p.113.

[13] Y. Tsumura, A. Sakakibara, K. Toyoda and S. Hara, Journal of Japan Institute of Light Metals Vol. 22 (1972), No. 6.

[14] S. El-Hadad, M. Eng. Thesis, UQAC, July (2003).

[15] A. T. Joenoes, J.E. Gruzleski, Magnesium Effects on the Microstructure of Unmodified and Modified Al-Si Alloys, Int. J. Cast Metals Res., Vol. 4, 1991, p.62.


[16] A. M. Samuel and F. H. Samuel, Interéts technologique et marchés potentiels des composites a matrice métallique``, Actes de colloque franco-canadien de septembre 1995, A. Thorel, J. Masounave et M. Suéry (eds. ), Les Presses de l, école des Mines de Paris, 1997, 81-92.

[17] W. M. Latimer (Ed. ), Oxidation Potentials (Prentice-Hall, Inc., Englewood Cliffs, N. J., 1952), pp.121-136.