The Microstructural Study of in Situ Al Alloy 319 Based Composite Reinforced by Iron-Based Intermetallic Produced by Stir Casting Process

Authors

School of Metallurgy and Materials Engineering, Iran University of Science and Technology

Abstract

The effect of stir casting process on the modification of the Fe-containing intermetallics formed in a cast in-situ composite based on Al-319 matrix alloy was studied in the present work. Microstructural observations using optical and scanning electron microscopes showed that the undesirable needle-like shape of the Fe-containing intermetallics (β) and also the coarse star-like α compounds were modified into the disc and spheroid shape particles with much less length to width ratio. The effect of parameters such as stirring temperature, cooling rate and Fe contents on the shape, size and distribution of intermetallic particles and eutectic Si blades were also studied. Results showed that the best condition to improve the shape, size and distribution of  intermetallic particles can be achieved at a stirring speed of 1200 rpm for 5 minutes at the vicinity of β needles nucleation temperature followed by casting into a metallic mold. Based on the results obtained from the current work, it can be concluded that the harmful morphology of the β intermetallic needles can be properly modified by applying a shearing force during stirring the molten alloy in the semi-solid state.

Keywords


1. Davis, J. R., Aluminum and Aluminum Alloys, p. 68, ASM International, 1993.
2. Warmuzek, M., Aluminum-Silicon Casting Alloys: an Atlas of Microfractographs, p. 124, ASM International, 2004.
3. Hatch, J. E., Aluminum: Properties and Physical Metallurgy, p. 424, ASM International, 1984.
4. Nafisi, S., Emadib, D., Shehata b, M. T., and Ghomashchi a, R., “Effects of Electromagnetic Stirring and Superheat on the Microstructural Characteristics of Al-Si-Fe Alloy”, Materials Science and Engineering A, Vol. 432, pp. 71-83, 2006.
5. Zhang, G., Wu, Sh., Jiang, H., and An, P., “Effects of Ultrasonic Vibration on the Iron-Containing Intermetallic Compounds of High Silicon Aluminum Alloy with 2% Fe”, Journal of Alloys and Compounds Vol. 492, pp. 482-487, 2010.
6. Zhang, L., Gao, J., Damoah, L. N. W., and Robertson, D. G., “Removal of Iron From Aluminum: A Review”, Mineral Processing and Extractive Metallurgy Review, Vol. 33, No. 2, pp. 99-157, 2012.
7. Moustafa, M. A., “Effect of Iron Content on the Formation of Β-Al5FeSi and Porosity in Al-Si Eutectic Alloys”, Journal of Materials Processing Technology, Vol. 209, No. 1, pp. 605-610, 2009.
8. Sreeja Kumari, S. S., Pillai, R. M., Rajan, T. P. D., and Pai, B. C., “Effects of Individual and Combined Additions of Be, Mn, Ca and Sr on the Solidification Behaviour, Structure and Mechanical Properties of Al-7Si-0.3Mg-0.8Fe Alloy”, Materials Science and Engineering A, Vol. 460-461, pp. 561-573, 2009.
9. Dinnis, C. M., Taylor, J. A., and Dahle, A. K.,“As-Cast Morphology of Iron-Intermetallics in Al-Si Foundry Alloys”, Scripta Materialia, Vol. 53, No. 8, pp. 955-958, 2005.
10. Narayanan, L. A., Samuel, F. H., and Gruzleski, J. E., “Crystallization Behavior of Iron-Containing Intermetallic Compounds in 319 Aluminum Alloy”, Metallurgical and Materials Transactions A, Vol. 25, No. 8, pp. 1761-1773, 1994.
11. Shabestari, S. G., and Gruzleski, J. E., “Gravity Segregation of Complex Intermetallic Compounds in Liquid Aluminum-Silicon Alloys”, Metallurgical and Materials Transactions A, Vol. 26, No. 4, pp. 999-1006, 1995.
12. Dinnis, C. M., Taylor, J. A., and Dahle, A. K., “Iron-Related Porosity in Al-Si-(Cu) Foundry Alloys”, Materials Science and Engineering A, Vol. 425, No. 1-2, pp. 286-296, 2006.
13. Fan, Z., Liu, G., and Hitchcock, M., “Solidification Behaviour under Intensive Forced Convection”, Materials Science and Engineering A, Vol. 413-414, pp. 229-235, 2005.
14. Lu, L., and Dahle, A. K., “Iron-Rich Intermetallic Phases and Their Role in Casting Defect Formation in Hypoeutectic Al-Si Alloys”, Metallurgical and Materials Transactions A, Vol. 36, No. 13, pp. 819-835, 2005.
15. Cao, X., and Campbell, J., “The Solidification Characteristics of Fe-Rich Intermetallics in Al-11.5Si-0.4Mg Cast Alloys”, Metallurgical and Materials Transactions A, Vol. 35, No. 5, pp. 1425-1435, 2004.
16. Fang, X., Shao, G., Liu, Y. Q., and Fan, Z., “Effects of Intensive Forced Melt Convection on the Mechanical Properties of Fe Containing Al-Si Based Alloys”, Materials Science and Engineering A, Vol. 445-446, pp. 65-72, 2007.
17. Sable, A. D., and Deshmukh, S. D., “Characterization of AlSiC Metal-Matrix by Stircasting” International Journal of Advanced Research in Engineering and Technology (IJARET), Vol. 3, pp. 226-234, 2012.

ارتقاء امنیت وب با وف ایرانی