Abstract
Tensile properties and fatigue crack propagation behavior of a 2195-T8 Al-Li alloy were investigated at different stress ratios, with particular emphasis on their dependence on specimen orientation. Specimens with orientations of 0, 15, 30, 45, and 90 deg to the rolling direction were tested. The alloy contained a strong brass-type texture and a profuse distribution of platelike precipitates of T 1 (Al2CuLi) phase on {111} matrix planes. Both tensile strength and fatigue thresholds were found to be strongly dependent on the specimen orientation, with the lowest values observed along the direction at 45 deg to the rolling direction. The effect of stress ratio on fatigue threshold could generally be explained by a modified crack closure concept. The growth of fatigue crack in this alloy was found to exhibit a significant crystallographic cracking and especially macroscopic crack deflection. The specimens oriented in the L-T + 45 deg had the smallest deflection angle, while the specimens in the L-T and T-L orientations exhibited a large deflection angle. The dependence of the fatigue threshold on the specimen orientation could be rationalized by considering an equivalent fatigue threshold calculated from both mode I and mode II values due to the crack deflection. A four-step approach on the basis of Schmid’s law combined with specific crystallographic textures is proposed to predict the fatigue crack deflection angle. Good agreement between the theoretical prediction and experimental results was observed.
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F.W. Gayle, W.T. Tack, G. Swanson, F.H. Heubaum, and J.R. Pickens: Scripta Metall. Mater., 1994, vol. 30, pp. 761–66.
D. Furrer and R. Noel: Adv. Mater. Processes, 1997, vol. 5, pp. 59–60.
B.P. Huang and Z.Q. Zheng: Scripta Mater., 1998, vol. 38, pp. 357–62.
B.P. Huang, Z.Q. Zheng, D.F. Yin, and Z.M. Mo: Mater. Sci. Forum, 1996, vols. 217–222, pp. 1239–44.
P.S. Chen, A.K. Kuruvilla, T.W. Malone, and W.P. Stanton: JMEPEG, 1998, vol. 7, pp. 682–90.
R. Crooks, Z. Wang, V.I. Levit, and R.N. Shenoy: Mater. Sci. Eng. A, 1998, vol. A257, pp. 145–52.
S.J. Hales and R.A. Hafley: Mater. Sci. Eng. A, 1998, vol. A257, pp. 153–64.
P.N. Kalu and L. Zhang: Scripta Mater., 1998, vol. 39, pp. 175–80.
K.H. Hou and W.A. Baeslack III: J. Mater. Sci. Lett., 1996, vol. 15, pp. 239–44.
K.H. Hou and W.A. Baeslack III: J. Mater. Sci. Lett., 1996, vol. 15, pp. 208–13.
J.C. Lippold and W. Lin: Mater. Sci. Forum, 1996, vols. 217–222, pp. 1685–90.
J.F. Sanders: Thin Solid Films, 1996, vol. 277, pp. 121–27.
P. Chien: Weld. J., 1998, vol. 77, pp. 45–47.
C.P. Blankenship, Jr. and E.A. Starke, Jr.: Fatigue Fract. Eng. Mater. Struct., 1991, vol. 14, pp. 103–14.
D.C. Slavik, C.P. Blankenship, Jr., E.A. Starke, Jr., and R.P. Gangloft: Metall. Trans. A, 1993, vol. 24A, pp. 1807–17.
C.P. Blankenship, Jr. and E.A. Starke, Jr.: Acta Metall. Mater., 1994, vol. 42, pp. 845–55.
D.L. Chen, M.C. Chaturvedi, N. Goel, and N.L. Richards: Int. J. Fatigue, 1999, vol. 21, pp. 1079–86.
K.T. Venkateswara Rao and R.O. Ritchie: Int. Mater. Rev., 1992, vol. 37, pp. 153–85.
I.M. Robertson: Mater. Forum, 1991, vol. 15, pp. 102–11.
V.B. Dutta, S. Suresh, and R.O. Ritchie: Metall. Trans. A, 1984, vol. 15A, pp. 1193–1207.
D.L. Chen, B. Weiss, and R. Stickler: Int. J. Fatigue, 1994, vol. 16, pp. 488–91.
I.G. Palmer, W.S. Miller, D.J. Lloyd, and M.J. Bull: in Aluminum-Lithium Alloys III, C. Baker, P.J. Gregson, S.J. Harris, and C.J. Peel, eds., The Institute of Metals, London, 1986, pp. 565–75.
M. Peters, K. Welpmann, and T.H. Sanders, Jr.: MRS-Europe, 7th Symp., Advanced Materials Research and Developments for Transport: Light Metals 1985, R.J.H. Wanhill, W.J.G. Bunk, and J.G. Wurm, eds., Les Editions de Physique, Les Ulis Cedex, France, 1985, vol. VII, pp. 63–70.
Z.X. Li and R. Mirshams: Mater. Sci. Forum, 1996, vols. 217–222, pp. 1233–38.
G.I. Taylor: J. Inst. Met., 1938, vol. 62, pp. 307–24.
J.F.W. Bishop and R. Hill: Phil. Mag., 1951, vol. 42, pp. 414–27 and 1298–1307.
W.G. Fricke, Jr. and M.A. Frzystupa: in Aluminum Alloys—Contemporary Research and Applications, A.K. Vasudevan and R.D. Doherty, eds., Academic Press, Inc., Boston, MA, 1989, pp. 563–78.
I. Sinclair and P.J. Gregson: Scripta Metall. Mater., 1994, vol. 30, pp. 1287–92.
B. Cotterell and J.R. Rice: Int. J. Fract., 1980, vol. 16, pp. 155–69.
S. Suresh and C.F. Shih: Int. J. Fract., 1986, vol. 30, pp. 237–59.
A.K. Vasudevan and S. Suresh: Mater. Sci. Eng., 1985, vol. 72, pp. 37–49.
K.T. Venkateswara Rao and R.O. Ritchie: Mater. Sci. Technol., 1989, vol. 5, pp. 882–907.
Y.B. Xu, L. Wang, Y. Zhang, Z.G. Wang, and Z.Q. Hu: Metall. Trans. A, 1991, vol. 22A, pp. 723–29.
X.J. Wu, W. Wallace, M.D. Raizenne, and A.K. Koul: Metall. Mater. Trans. A, 1994, vol. 25A, pp. 575–88.
G.O. Rading and J.T. Berry: Mater. Sci. Eng. A, 1996, vol. A219, pp. 192–201.
R.W.K. Honeycombe: The Plastic Deformation of Metals, Edward Arnold (Publishers) Ltd., London, 1968, pp. 17–20.
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Chen, D.L., Chaturvedi, M.C. Near-threshold fatigue crack growth behavior of 2195 aluminum-lithium-alloy—prediction of crack propagation direction and influence of stress ratio. Metall Mater Trans A 31, 1531–1541 (2000). https://doi.org/10.1007/s11661-000-0164-5
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DOI: https://doi.org/10.1007/s11661-000-0164-5