Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 30455
High Temperature Deformation Behavior of Cr-containing Superplastic Iron Aluminide

Authors: Tae Kwon Ha, Woo Young Jung, Seok Hong Min

Abstract:

Superplastic deformation and high temperature load relaxation behavior of coarse-grained iron aluminides with the composition of Fe-28 at.% Al have been investigated. A series of load relaxation and tensile tests were conducted at temperatures ranging from 600 to 850oC. The flow curves obtained from load relaxation tests were found to have a sigmoidal shape and to exhibit stress vs. strain rate data in a very wide strain rate range from 10-7/s to 10-2/s. Tensile tests have been conducted at various initial strain rates ranging from 3×10-5/s to 1×10-2/s. Maximum elongation of ~500 % was obtained at the initial strain rate of 3×10-5/s and the maximum strain rate sensitivity was found to be 0.68 at 850oC in binary Fe-28Al alloy. Microstructure observation through the optical microscopy (OM) and the electron back-scattered diffraction (EBSD) technique has been carried out on the deformed specimens and it has revealed the evidences for grain boundary migration and grain refinement to occur during superplastic deformation, suggesting the dynamic recrystallization mechanism. The addition of Cr by the amount of 5 at.% appeared to deteriorate the superplasticity of the binary iron aluminide. By applying the internal variable theory of structural superplasticity, the addition of Cr has been revealed to lower the contribution of the frictional resistance to dislocation glide during high temperature deformation of the Fe3Al alloy.

Keywords: dynamic recrystallization, Iron aluminide (Fe3Al), large grain size, structural superplasticity, chromium (Cr)

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1332826

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1423

References:


[1] A. H. Chokshi, A. K. Mukherjee, and T. G. Langdon, Mater. Sci. Eng., vol. R10, p. 237, 1993.
[2] O. D. Sherby, and J. Wadsworth, Prog. Mater. Sci., vol. 33, p. 169, 1989.
[3] K. A. Padmanabhan, and G. J. Davis, "Superplasticity", Springer-Verlag, New York, NY, p. 11, 1980.
[4] T. G. Nieh, J. Wadsworth, and O. D. Sherby, "Superplasticity in Metals and Ceramics", Cambridge Univ. Press, Cambridge, p. 125, 1997.
[5] D. Lin, T. L. Lin, A. Shan and M. Chen, Intermetallics, vol. 4, p. 489, 1996.
[6] D. Lin, D. Li, and Y. Liu, Intermetallics, vol. 6, p. 243, 1998.
[7] J. P. Chu, I. M. Liu, J. H. Wu, W. Kai, J. Y. Wang, and K. Inoue, Mater. Sci. Eng., vol. A258, p. 236, 1998.
[8] J. P. Chu, H. Y. Yasda, Y. Umakoshi, and K. Inoue, Intermetallics, vol. 8, p. 39, 2000.
[9] E. W. Hart, "Stress Relaxation Testing", A. Fox ed., ASTM, Baltimore, Md., p. 5, 1979.
[10] T. K. Ha, and Y. W. Chang, Acta Mater., vol. 46, p. 2741, 1998.
[11] D. Lee, and E. W. Hart, Metall. Trans., vol. 2A, p. 1245, 1971.
[12] C. G. McKamey, P. J. Masiasz, J. W. Jones, J. Mater. Res., vol. 7, p. 2089, 1992.