Novel Concept of Austenitic Heat Resistant Steels Strengthened by Intermetallics

Abstract:

Alloy design concept for the development of a new class of austenitic heat resistant steels strengthened by Fe2M Laves phases (M: transition metals) has been proposed. The phase diagram studies on Fe-Ni-M ternary systems demonstrate that Fe2Nb with C14 structure is the most promising, because more than 40at% Ni can dissolve into the Fe sublattice sites and large γ+Fe2Nb two-phase region exists along the equi-niobium concentration direction. The control of the c/a ratio of the Laves phase using the composition homogeneity region by alloying makes it possible to disperse the Laves phase finely in the γ matrix. Based on the knowledge, a model alloy Fe-20Cr- 30Ni-2Nb (at%) was proposed and the TTP diagram of the Laves phase was constructed. The Laves phase homogeneously nucleates in the matrix and its fine morphology remains almost unchanged even after long-term aging at 1073K.

• Periodical: Materials Science Forum (Volumes 539-543)
• Pages: 3012-3017
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.539-543.3012
• Online since: March 2007
• Authors: Masao Takeyama
• Keywords: Axial Ratio, Fe₂Nb Laves Phase, Fe-Ni-M Ternary Phase Equilibria, Lattice Parameter, Precipitation Morphology

References

[1] F. Masuyama: Report of JSPS 123rd Committee on Heat-Resisting Materials and Alloys, 38 (1997), p.211.

[2] M. Igarashi, A. Iseda and T. Kan: ib (id)., 44 (2003)p.205.

[3] Y. Kadoya: ib (id)., 44 (2003), p.215.

[4] M. Takeyama: ib (id)., 45 (2004), 51.

[5] H. Okamoto: Phase diagrams for Binary Alloys (ASM International 2000).

[6] M. Takeyama, S. Morita, A. Yamauchi, M. Yamanaka and T. Matsuo: Superalloys 718, 625, 706 and Various Derivatives, Eds. by E. A. Loria, TMS, (2001) p.333.

[7] M. Takeyama, H. Yokota, M. M. Ghanem and T. Matsuo: Journal of Materials Processing Technology (Proceedings of THERMEC'2000) 117, 3 (2001). [CD-ROM], Session D7.

[8] M. Takeyama, N. Gomi, S. Morita, T. Matsuo: MRS Symp. Proc. Vol. 842 (2005), p.461.

[9] S. Ishikawa, N. Gomi, T. Matsuo and M. Takeyama: Report of JSPS 123rd Committee on Heat-Resisting Materials and Alloys, 46 (2005), p.25.

[10] B. Weiss and R. Stickler: Metall. Trans. A Vol. 3 (1972), p, 851.

[11] Y, Minami, H. Kimura and Y. Ihara: Mate. Sci. & Tech., Vol. 2 (1986), p.795.

[12] H. Tanaka, M. Murata, K. Kamihara, M. Yamazaki, K. Kimura and F. Abe: Report of JSPS 123rd Committee on Heat-Resisting Materials and Alloys, 47 (2006), p.31.

[13] H. Oikawa: Technology Report of the Tohoku University, vol. 47, 2 (1982), p.215.