Hostname: page-component-76fb5796d-skm99 Total loading time: 0 Render date: 2024-04-27T00:29:06.344Z Has data issue: false hasContentIssue false
  • English
  • Français

Effect of grain boundary characteristics on hot tearing in directional solidification of superalloys

Published online by Cambridge University Press:  03 March 2011

Yizhou Zhou ,
Andreas Volek  and
Robert F. Singer
Yizhou Zhou
Affiliation:
WTM Institute, Department of Materials Science, University of Erlangen–Nürnberg, 91058 Erlangen, Germany
Andreas Volek
Affiliation:
WTM Institute, Department of Materials Science, University of Erlangen–Nürnberg, 91058 Erlangen, Germany
Robert F. Singer*
Affiliation:
WTM Institute, Department of Materials Science, University of Erlangen–Nürnberg, 91058 Erlangen, Germany
*
a) Address all correspondence to this author. e-mail: robert.singer@ww.uni-erlangen.de
Get access

Abstract

The effect of grain boundary (GB) misorientation on hot tearing susceptibility of directionally solidified (DS) nickel-based superalloys was explored. We found that the castability of second generation nickel-based superalloy CMSX-4 is inferior to DS superalloy IN792, an alloy well known for bad castability. The castability of CMSX-4 is somewhat improved at a higher solidification rate. The hot tearing tendency increases with increasing GB misorientation angle. As feeding tendency becomes greater with increasing misorientation, this points to the importance of GB cohesion for solidification cracking in the alloy. Microstructure investigation reveals that hot tearing is associated with formation of continuous gamma and gamma prime eutectic films at the GB in CMSX-4. We assume that the gamma and gamma prime eutectic, which reflects the remaining liquid at the end of solidification, prevents the impinging dendrite arms from touching and in this way decreases cohesion.

Keywords

DefectsDirectional solidificationGrain boundaries
Type
Articles
Information
Journal of Materials Research , Volume 21 , Issue 9 , September 2006 , pp. 2361 - 2370
Copyright
Copyright © Materials Research Society 2006

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1Versnyder, F.L. and Shank, M.E.: The development of columnar grain and single crystal high temperature materials through directional solidification. Mater. Sci. Eng. 6, 213 (1970).Google Scholar
2Pollock, T.M. and Murphy, W.H.: The breakdown of single-crystal solidification in high refractory nickel-base alloys. Metall. Mater. Trans. A 27, 1081 (1996).Google Scholar
3Pollock, T.M.: The growth and elevated temperature stability of high refractory nickel-base single crystals. Mater. Sci. Eng., B 32, 255 (1995).Google Scholar
4Pollock, T.M., Murphy, W.H., Goldman, E.H., Uram, D.L., and Tu, J.S.: Grain defect formation during directional solidification of nickel base single crystals, in Superalloys 1992, edited by Antolovich, S.D., Stusrud, R.W., MacKay, R.A., Anton, D.L., Khan, T., Kissinger, R.D. and Klarstrom, D.L. (TMS, Warrendale, PA, 1992), p. 125.Google Scholar
5D’Souza, N., Ardakani, M.G., McLean, M., and Shollock, B.A.: Directional and single crystal solidification of Ni-base superalloys: Part I. The role of curved isotherms on grain selection. Metall. Mater. Trans. A 31, 2877 (2000).Google Scholar
6Ardakani, M.G., D’Souza, N., Shollock, B.A., and McLean, M.: Directional and single crystal solidification of Ni-base superalloys: Part II. Coincidence site lattice character of grain boundaries. Metall. Mater. Trans. A 31, 2887 (2000).Google Scholar
7Ardakani, M.G., D’Souza, N., Wagner, A., Shollock, B.A., and McLean, M.: Competitive grain growth and texture evolution during directional solidification of superalloys, in Superalloys 1992, edited by Pollock, T.M., Kissinger, R.D., Bowman, R.R., Green, K.A., McLean, M., Olson, S. and Schirra, J.J. (TMS, Warrendale, PA, 2000), p. 219.Google Scholar
8Sigworth, G.K.: Hot tearing of metals. AFS Trans. 155, 1053 (1996).Google Scholar
9Campbell, J.: Castings (Butterworth-Heinemann Ltd., London, 1991), p. 219229.Google Scholar
10Clyne, T.W. and Davies, G.J.: The influence of composition on solidification cracking susceptibility in binary alloy systems. Br. Foundrymen 74, 65 (1981).Google Scholar
11Rappaz, M., Drezet, J.M., and Gremaud, M.: A new hot-tearing criterion. Metall. Mater. Trans. A 30, 449 (1999).Google Scholar
12Zhang, J. and Singer, R.F.: Effect of grain-boundary characteristics on castability of nickel-base superalloys. Metall. Mater. Trans. A 35, 939 (2004).Google Scholar
13Zhou, Y.Z., Volek, A., and Singer, R.F.: Influence of solidification conditions on the castability of nickel-base superalloy IN792. Metall. Mater. Trans. A 36, 651 (2005).Google Scholar
14Zhang, J. and Singer, R.F.: Effect of hafnium on the castability of directionally solidified nickel-base superalloys. Z. Metallkd. 93, 806 (2002).CrossRefGoogle Scholar
15Zhang, J. and Singer, R.F.: Hot tearing of nickel-based superalloys during directional solidification. Acta Mater. 50, 1869 (2002).Google Scholar
16Wills, V.A. and McCartney, D.G.: A comparative study of solidification features in nickel-base superalloys: Microstructural evolution and microsegregation. Mater. Sci. Eng., A 145, 223 (1991).Google Scholar
17Hilliard, J.E. and Cahn, J.W.: An evaluation of procedures in quantitative metallography for volume-fraction analysis. Trans. Metall. Soc. AIME 221, 344 (1961).Google Scholar
18Kurz, W. and Fisher, D.J.: Dendrite growth at the limit of stability: Tip radius and spacing. Acta Metall. 29, 11 (1981).Google Scholar
19Tin, S. and Pollock, T.M.: Stabilization of thermosolutal convective instabilities in Ni-base single-crystal superalloys: Carbide precipitation and Rayleigh numbers. Metall. Mater. Trans. A 34, 1953 (2003).Google Scholar
20Tin, S., Pollock, T.M., and Murphy, W.: Stabilization of thermosolutal convective instabilities in Ni-base single-crystal superalloys: Carbon additions and freckle formation. Metall. Mater. Trans. A 32, 1743 (2001).Google Scholar
21Tin, S. and Pollock, T.M.: Phase instabilities and carbon additions in single-crystal nickel-base superalloys. Mater. Sci. Eng., A 348, 111 (2003).Google Scholar
22Duhl, D.N. and Sullivan, C.P.: Some effects of hafnium additions on the mechanical properties of a columnar-grained nickel-base superalloys. J. Metall. 23, 38 (1971).Google Scholar
23Doherty, J.E., Kear, B.H., and Giamei, A.F.: On the origin of ductility enhancement in Hf-doped Mar-M200. J. Metall. 23, 59 (1971).Google Scholar