Hostname: page-component-78c5997874-fbnjt Total loading time: 0 Render date: 2024-11-02T19:18:52.510Z Has data issue: false hasContentIssue false
  • English
  • Français

Micromechanisms of Deformation and Fracture in a Ti3Al-Nb Alloy

Published online by Cambridge University Press:  26 February 2011

A.S. Akkurt ,
G. Liu  and
G.M. Bond
A.S. Akkurt
Affiliation:
Department of Materials and Metallurgical Engineering, New Mexico Tech, Socorro, New Mexico 87801
G. Liu
Affiliation:
Department of Materials and Metallurgical Engineering, New Mexico Tech, Socorro, New Mexico 87801
G.M. Bond
Affiliation:
Department of Materials and Metallurgical Engineering, New Mexico Tech, Socorro, New Mexico 87801
Get access

Abstract

The object of this study has been to gain a greater understanding of deformation and fracture processes in a Ti-24Al-11Nb (at %) alloy. The in-situ TEM deformation technique has been used to observe these processes as they occur. Material characterization studies revealed the existence of three different crystal structures in the material (α2,B2 and orthorhombic (0)). Slip is first initiated in the B2 and 0 phases. Although dislocations are observed in the α2 phase in the deformed material, they are seen only in high-stress regions and only in some laths. While numerous dislocations may be injected into the corresponding grain and phase boundaries, slip does not easily propagate into the α2 phase. Cracks are seen to originate most frequently in the regions transformed fully to α2 laths, and sometimes in the regions that contain α2 laths at prior β grain boundaries. Failure of grain or phase boundaries in the B2 or 0 phases where no α2 is present is not observed. Crack branching in the α2 phase is common, particularly in the vicinity of phase boundaries. Crack propagation in the B2 and 0 phases occurs by plastic thinning, and cracks formed in the α2 lath regions are either stopped in phase boundaries or blunted in the neighboring 0 or B2 grains.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 213: Symposium Q – High-Temperature Ordered Intermetallic Alloys IV , 1990 , 455
Copyright
Copyright © Materials Research Society 1991

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

1. Lipsitt, H.A., Schechtman, D. and Schafrik, R.E., Met. Trans. 11A, 1369 (1980).Google Scholar
2. Blackburn, M.J. and Williams, J.C., Trans. ASM 62, 398 (1969).Google Scholar
3. Williams, J.C. and Blackburn, M.J. in Ordered Alloys: Structural Applications and Physical Metallurgy, edited by Kear, B.H., Sims, C.T., Stoloff, N.S. and Westbrook, J.H. (Claitor's, Baton Rouge, LA, 1970), pp. 425–445.Google Scholar
4. Court, S.A., Lofvander, J.P.A., Stucke, M.A. and Kurath, P. in High- Temperature Ordered Intermetallic Alloys III, edited by Liu, C.T., Taub, A.I., Stoloff, N.S. and Koch, C.C. (Mater. Res. Soc. Proc. 133, Pittsburgh, PA, 1989), pp. 675–680.Google Scholar
5. Blackburn, M.J. and Snmith, M.P., Air Force Tech. Report, AFWAL-TR-80–4175, 1980.Google Scholar
6. Mokhanova, E.K., Phase Diagrams of Titanium Alloys, Israel Programme for Scientific Translations, Jerusalem, (1965) 167.Google Scholar
7. Bendersky, L.A. and Boettinger, W.J. in High-Temperature Ordered Intermetallic Alloys III, edited by Liu, C.T., Taub, A.I., Stoloff, N.S. and Koch, C.C. (Mater. Res. Soc. Proc. 133, Pittsburgh, PA, 1989), pp. 45–50.Google Scholar
8. Kestner-Weykamp, H.T., Ward, C.H., Brode, T.F. and Kaufman, M.J., Scripta Metall. 23, 1697 (1989).Google Scholar
9. Banerjee, D., Gogia, A.K., Nandy, T.K. and Joshi, V.A., Acta Metall. 36, 871 (1988).Google Scholar
10. Muraleedharan, K., Gogia, A.K., Nandy, T.K. and Banerjee, D., presented at the Metallurgical Society Fall Meeting, Indianapolis, IN, 1989 (unpublished).Google Scholar
11. Weykamp, H.T., Baker, D.R., Paxton, D.M. and Kaufman, M.J., Scripta Metall. et Materialia 24, 445 (1990).Google Scholar
12. Peters, J.A. and Bassi, C., Scripta Metall. et Materialia 24, 915 (1990).CrossRefGoogle Scholar
13. Muraleedharan, K., Naidu, S.V.N. and Banerjee, D., Scripta Metall. et Materialia 24, 27 (1990).Google Scholar
14. Banerjee, D., Gogia, A.K. and Nandy, T.K., Met. Trans. 21A, 627 (1990).Google Scholar
15. Lukasak, D.A., MS thesis, Pennsylvania State University, 1988.Google Scholar
16. Gittis, S.J. and Koss, D.A. in High-Temperature Ordered Intermetallic Alloys III, edited by Liu, C.T., Taub, A.I., Stoloff, N.S. and Koch, C.C. (Mater. Res. Soc. Proc. 133, Pittsburgh, PA, 1989), pp. 323–328.Google Scholar
17. Koss, D.A., Lukasak, D.A. and Gittis, S.J., presented at the Metallurgical Society Fall Meeting, Indianapolis, IN, 1989 (unpublished).Google Scholar
18. Gogia, A.K., Banerjee, D. and Nandy, T.K., Met. Trans. 21A, 609 (1990).CrossRefGoogle Scholar
19. Akkurt, A.S., M.S. thesis, New Mexico Institute of Mining and Technology, 1990.Google Scholar