Abstract
The plastic anisotropy resulting from the initial deformation microstructure and various aging treatments applied to several regions of an AA2090 near-net-shape extrusion has been investigated. Yield behavior was measured by uniaxial compression in multiple orientations of each region. Two models of the plastic anisotropy were generated: the Taylor/Bishop-Hill model, based on crystallographic texture, and the plastic inclusion model, developed by Hosford and Zeisloft,[5] which incorporates anisotropic-precipitate effects. In overaged conditions, the Taylor/Bishop-Hill model adequately describes the observed plastic anisotropy. As the strengthening increment due to second-phase particles increases, there is a concurrent increase in the magnitude of the precipitate contribution to anisotropy. This anisotropy can not be accurately predicted solely by crystallographic texture. By incorporation of terms describing the precipitate anisotropy, the plastic inclusion model correctly predicts the yield strength variation in all regions tested. Examination of the fundamental interaction between matrix and precipitation strengthening reveals that there is a stronger basis for taking the critical resolved shear stress (CRSS) of the precipitates as a constant, rather than their effective yield strength. This consideration provides a more consistent and accurate form of the plastic inclusion model.
Similar content being viewed by others
References
G.Y. Chin and W.L. Mammel:Trans. TMS-AIME, 1969, vol. 245, pp. 1211–14.
U.F. Kocks:Metall. Trans., 1970, vol. 1, pp. 1121–43.
A.K. Vasudévan, W.G. Fricke, Jr., R.C. Malcolm, R.J. Bucci, M.A. Przystupa, and F. Barlat:Metall. Trans. A, 1988, vol. 19A, pp. 731–32.
U.F. Kocks and H. Chandra:Acta Metall., 1982, vol. 30, pp. 695–709.
W.F. Hosford and R.H. Zeisloft:Metall. Trans., 1972, vol. 3, pp. 113–21.
P. Bate, W.T. Roberts, and D.V. Wilson:Acta Metall., 1981, vol. 29, pp. 1797–1814.
L.M. Brown and D.R. Clarke:Acta Metall., 1975, vol. 23, pp. 821–30.
L.M. Brown and W.M. Stobbs:Phil. Mag., 1971, vol. 23, pp. 1185–99.
J.C. Huang and A.J. Ardell:J. Phys., 1987, vol. 48, pp. C3-373–C3-383.
J.C. Huang and A.J. Ardell:Acta Metall., 1988, vol. 36, pp. 2995–3006.
C. Tome, G.R. Canova, U.F. Kocks, N. Christodoulou, and J.J. Jonas:Acta Metall., 1984, vol. 32, pp. 1637–53.
J.S. Kallend, U.F. Kocks, A.D. Rollett, and H.-R. Wenk:Mater. Sci. Eng., 1991, vol. A132, pp. 1–11.
D.B. Williams:Practical Analytical Electron Microscopy in Materials Science, Verlag Chemie Int., New York, NY, 1984, pp. 78–79.
E.E. Underwood:Quantitative Stereology, Addison-Wesley Publishing Company, Reading, MA, 1970.
J.E. Hilliard:Trans. TMS-AIME, 1962, vol. 224, pp. 906–17.
W.D. Pollock and S.J. Hales:4th Int. Conf. on Aluminum Alloys, T.H. Sanders, Jr. and E.A. Starke, Jr., eds., Georgia Institute of Technology, Atlanta, GA, 1994, pp. 358–65.
M.A. Przystupa, A.K. Vasudévan, and W.G. Fricke, Jr.:ICOTOM-8 Conf. Proc., J.S. Kallend and G. Gottstein, eds., TMS, Santa Fe, NM, 1988, pp. 1051–57.
U.F. Kocks:ICOTOM-8 Conf. Proc., J.S. Kallend and G. Gottstein, eds., TMS, Santa Fe, NM, 1988, pp. 31–36.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Lyttle, M.T., Wert, J.A. The plastic anisotropy of an Al-Li-Cu-Zr alloy extrusion in unidirectional deformation. Metall Mater Trans A 27, 3503–3512 (1996). https://doi.org/10.1007/BF02595442
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF02595442