Hostname: page-component-745bb68f8f-f46jp Total loading time: 0 Render date: 2025-01-27T16:20:43.346Z Has data issue: false hasContentIssue false
  • English
  • Français

Development of Microstructures with Improved Cryogenic Toughness Through Local Variations in Stress State: Aluminum-Lithium Alloys

Published online by Cambridge University Press:  28 February 2011

K. T. Venkateswara Rao  and
R. O. Ritchie
K. T. Venkateswara Rao
Affiliation:
Center for Advanced Materials, Lawrence Berkeley Laboratory and Department of Materials Science and Mineral Engineering, University of California, Berkeley, CA 94720
R. O. Ritchie
Affiliation:
Center for Advanced Materials, Lawrence Berkeley Laboratory and Department of Materials Science and Mineral Engineering, University of California, Berkeley, CA 94720
Get access

Abstract

Microstructurally-induced changes in the local stress state (triaxial constraint) and their effect on fracture-toughness behavior are examined at ambient and cryogenic temperatures in an Al-Li-Cu-Zr alloy, processed in the form of 12.7 mm-thick "naturally laminated" plate containing aligned-weak interfaces and 1.6 mm-thin unlaminated sheet. It is shown that marked improvements in long-transverse (L-T) toughness can be achieved in the plate material at cryogenic temperatures by promoting through-thickness delamination along these interfaces, which relaxes local constraint and promotes a fracture-mode transition from global plane strain to local plane stress. Conversely, in thin sheet material, the absence of such interface delamination leads to a reduction in toughness with decrease in temperature, consistent with the greater degree of crack-tip constraint.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 186: Symposium I – Alloy Phase Stability and Design , 1990 , 421
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

1. Knott, J. F., Mater. Sci. Eng. 2, 1 (1971).Google Scholar
2. Hertzberg, R. W., Deformation and Fracture Mechanics of Engineering Materials, 3rd ed. (John Wiley & Sons Inc., New York, 1989), p. 353.Google Scholar
3. Broek, D., Elementary Engineering Fracture Mechanics, 3rd ed. (Martinus Nijhoff Publishers, The Hague, 1982), p. 101.Google Scholar
4. Irwin, G. R., J. Basic Eng. 82, 417 (1960).Google Scholar
5. Khadkikar, P. S., Lewandowski, J. J. and Vedula, K., Metall. Trans. A 20A, 1247 (1989).Google Scholar
6. Hutchinson, J. W., J. Mech. Phys. Sol. 16, 13 (1968).Google Scholar
7. Rice, J. R. and Rosengren, G. R., J. Mech. Phys. Sol. 16, 1 (1968).Google Scholar
8. Embury, J. D., Petch, N. J., Wraith, A. E. and Wright, E. S., Trans. Met. Soc. AIME 239, 114 (1967).Google Scholar
9. Leichter, H. L., J. Spacecraft 3, 1113 (1966).Google Scholar
10. Evans, A. G. and Marshall, D. B., Acta Metall. 37, 2567 (1989).Google Scholar
11. Wadsworth, J., Kum, D. W. and Sherby, O. D., Met. Prog. 129, 61 (1986).Google Scholar
12. Rao, K. T. Venkateswara, Yu, W. and Ritchie, R. O., Metall. Trans. A 20A, 485 (1989).Google Scholar
13. Bucci, R. J., Malcolm, R. C., Colvin, E. L., Murtha, S. and James, R. S., Alcoa Report No. NSWC TR 89-106, 1989.Google Scholar
14. Cottrell, A. H., in Properties of Reactor Materials and Effects of Radiation Damage, edited by Litter, D. J. (Butterworth London, 1962), p. 5.Google Scholar
15. Webster, D., Metall. Trans. A 18A, 2181 (1987).Google Scholar
16. Glazer, J., Verzasconi, S. L., Sawtell, R. R. and Morris, J. W., Metall. Trans. A 18A, 1695 (1987).Google Scholar
17. Jata, K. V. and Starke, E. A., Scripta Metall. 22, 1553 (1988).Google Scholar