Intergranular Cracking in Alloy 690 with Nb, Mo, and Hf Additions: In Situ SEM High Temperature Deformation Study

Abstract:

The microstructure behavior during high temperature deformation of Ni-base alloys based on alloy 690 modified with Nb, Mo, and Hf additions were studied. Optical and electron microscopy were used to characterize these materials and the results were compared with Calphad-based modeling results. The alloys behavior was studied between 500 and 1000 °C using an in-situ high temperature deformation test. The role of precipitates on the grain boundary morphology and their effect on grain boundary sliding and the mechanism of ductility-dip cracking are discussed. Both, undulated grain boundaries and primary intra-granular precipitates improved the alloy DDC resistance.

• Periodical: Materials Science Forum (Volumes 706-709)
• Pages: 945-950
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.706-709.945
• Online since: January 2012
• Authors: Jimy S. Unfried, Antonio Jose Ramirez
• Keywords: Ductility-Dip Cracking, Fracture, Grain Boundary, Nickel Alloy

References

[1] M.A. Arkoosh and N.F. Fiore: Metallurgical transactions, Vol. 3 (1972), p.2235.

[2] F.N. Rhines and P.J. Wray: Transactions of the ASM, 54, (1961) p.117.

[3] D.M. Haddrill and R.G. Baker: British welding journal, (1965) p.411.

[4] F.F. Noecker II and J.N. DuPont: Welding Journal, Vol. 88, (2009) p. 7s.

[5] N.E. Nissley and J.C. Lippold: Welding journal, Vol. 88, (2009) p. 131s.

[6] A.J. Ramirez, J.C. Lippold: Mat. Sci. and Eng. A 380, (2004) p.259.

[7] R.C. Gifkins: Materials characterization 32, (1994) p.59.

[8] T.G. Langdon: Materials science 41, (2006) p.597.

[9] A.J. Ramirez and J.C. Lippold, in: Hot Cracking Phenomena in welds, edited by T. Böllinghaus, H. Herold. (2005) p.19.

DOI: 10.1007/b139103

[10] M.G. Collins, A.J. Ramirez, J.C. Lippold: Welding Journal 83, (2004) p. 39s.

[11] S. Yamaguchi, Et al.: Phil. Trans. R. Soc. Lond. A, 295, (1980) p.122.

[12] A.J. Ramirez, C.M. Garzón, in: Hot Cracking Phenomena in welds II, edited by T. Böllinghaus, H. Herold, C. Cross, J.C. Lippold, (2008) p.427.

DOI: 10.1007/978-3-540-78628-3

[13] L.N. Zimina, N.N. Burova, O.V. Makushok: Met. Sci. and heat treatment, 28(2), (1986) p.130.

[14] J.M. Duhl, C.P. Sullivan: Journal of metals, (1971) pp.38-40.

[15] E.A. Torres, F.G. Paternella, R. Caram, A.J. Ramirez, , In: 8th international conference on trends in welding research, Pine-Mountain, GA-USA, (2009) p.354.

[16] J. Unfried S., Et Al., In: Mathematical Modelling of Weld Phenomena 9, edited by Maney. H Cerjak; H K D H Bhadeshia and E Kozeschnik, (2010) p.983.

[17] G.D. Pigrova: Metal science and heat treatment, 47, 11-12, (2005) p.544.

[18] E.A. Torres, R. Caram, A.J. Ramirez: Materials science forum, 638-642, (2010) p.2858.

[19] J. Unfried S., E. A. Torres, A. J. Ramirez, In: Hot Cracking Phenomena in Welds III, edited by T. Böllinghaus, H. Herold, C. Cross, (2011) in press.

[20] C.R.M. Afonso, J.C. Lippold, A.J. Ramirez: submitted to Metallurgical transactions A (2010).