Spray-Formed 50Si-50Al Alloy Deformed in the Semi-Solid State

Abstract:

50Si-50Al alloys were synthesized by the Spray Forming process, and were further deformed in the semi-solid state. The spray-formed microstructure consists of small equiaxed primary Si in 3-5 μm scale. For semi-solid deformation at 650°C at solid fraction (fs) of 0.4, the stress increases initially to reach the peak stress, then decreases to a plateau level, followed by last stage of stress climbing, and the effects of the deformation speeds on the stress level are significant, but not large. For deformation at 750°Cat fs of 0.31, the stress increases initially, then increases at a slower rate, followed by last stage of fast climbing, and the lower the deformation speed is, the higher the deformation stress. The average deformation stress needed at 650 °C was much higher that that needed at 750 °C. The deformation was inhomogeneous at 650°C to become pieces of connected semi-solid clusters, while the deformation was much more homogeneous at 750°C.

• Periodical: Key Engineering Materials (Volume 573)
• Pages: 37-41
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.573.37
• Online since: September 2013
• Authors: Hong Chih Hsu, Chi Tsao
• Keywords: 50Si-50Al Alloy, High Solid Fraction, Semi-Solid Processing, Spray Forming

References

[1] Chen, C. P. and Tsao, C.-Y. A.: Semi-Solid Deformation of Non-Dendritic Structures – Phenomenological Behavior", Acta mater, Vol.45, No.5(1997), 1955-1968

DOI: 10.1016/s1359-6454(96)00312-6

[2] Bergsma, S. C., Tolle, M. C., Kassner , M. E, Li, X. and Evangelista , E.: Semi-Solid Transformations of Al-Si Alloys and the Resulting Mechanical Properties, Material Science and Engineering, A237 (1997), 24-34

DOI: 10.1016/s0921-5093(97)00112-3

[3] Tzimas, E. and Zavaliangos , A.: Mechanical Behavior of Alloys with Equiaxed microstructure in the semisolid state at high solid content, Acta Mater, Vol. 47 (1999), 517-528

DOI: 10.1016/s1359-6454(98)00356-5

[4] Ward, P. J., Atkinson, H. V., Anderson, P. R. G., Elias, L. G, Garcia, B., Kahlen, L. and Rodriguez-Ibabe, J-M: Semi-Solid Processing of Novel MMCs Based on Hypereutectic Aluminum-Silicon Alloys, Acta Mater, vol. 44, No.5 (1998), 1717-1727

DOI: 10.1016/1359-6454(95)00356-8

[5] Tzimas, Zavaliangos, E., A., Lawley, A. and Pumberger, C.: Physical Mechanisms of the Flow Resistance of Semisolid Materials at a High Volume Fraction of Solid", Proceedings of the 4th International Conference on Semi-Solid Processing of Alloys and Composites, Sheffield, June 1996.