Abstract
We describe a new approach for modeling the age-hardening behavior of Al-Si-Cu cast alloys, that utilizes recently proposed micromechanical models of precipitation strengthening which connect key microstructural parameters for realistic precipitate morphologies (e.g., {100} plates) with the age-hardening response. This approach is illustrated and tested for a series of 319-type Al alloys (which we refer to as W319), where the microstructural parameters of ϑ′ plates measured by transmission electron microscopy and a first-principles/computational-thermodynamics model of ϑ′ volume fraction are used in the micromechanical model to predict precipitation strengthening. Thus, the precipitation-strengthening contribution contains no free parameters in our approach. An aging temperature- and time-dependent component that describes the strengthening of the Guinier-Preston (GP) zones and solid-solution copper, as well as a constant intrinsic strength, is combined with the calculated precipitation strength to predict the yield strength with a minimum of fitting parameters. This yield-strength model provides a good predictor of the yield strength of W319, and the methodology should be more generally applicable to all industrial cast alloys strengthened primarily by ϑ′. We also discuss limitations of the present approach and point to areas for improvement in future studies.
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H.R. Shercliff and M.F. Ashby: Acta Metall. Mater., 1990, vol. 38, pp. 1789–802.
Ch.-A. Gandin, Y. Brechet, M. Rappaz, G. Canova, M. Ashby, and H. Shercliff: Acta Mater., 2002, vol. 50, p. 901.
P.A. Rometsch and G.B. Schaffer: Mater. Sci. Eng., A, 2002, vol. A325, p. 424.
O. Grong and H. Shercliff: Prog. Mater. Sci., 2002, vol. 47, p. 163.
O.R. Myhr, O. Grong, and S.J. Andersen: Acta Mater., 2001, vol. 49, p. 65.
A. Deschamps and Y. Brechet: Acta Mater., 1999, vol. 47, p. 293.
M.J. Starink, P. Wang, I. Sinclair, and P.J. Gregson: Acta Mater., 1999, vol. 47, p. 3841.
J.F. Nie and B.C. Muddle: J. Phase Equilibrium, 1998, vol. 19, pp. 543–51.
A.W. Zhu and E.A.J. Starke: Acta Mater., 1999, vol. 47, pp. 3263–69.
A.W. Zhu, A.W. Chen, and E.A.J. Starke, Jr.: Acta Mater., 2000, vol. 48, pp. 2239–46.
J.D. Embury, D.J. Lloyd, and T.R. Ramachandran: in Aluminum Alloys—Contemporary Research and Applications, A.K. Vasudevan and R.D. Doherty, eds., Academic Press, New York, NY, 1989.
D.L. Gilmore and E.A. Starke: Metall. Mater. Trans. A, 1997, vol. 28A, pp. 1399–415.
E. Hornbogen and E.A. Starke, Jr.: Acta Mater., 1993, vol. 41, p. 1.
A.J. Ardell: Metall. Trans. A, 1985, vol. 16A, pp. 2131–65.
A.J. Ardell: in Encyclopedia of Materials Science and Engineering, M.B. Bever, ed., Pergamon Press, Oxford, United Kingdom, 1986, p. 3882.
C. Cloutier, P. Reeber-Schmansky, J.W. Jones, and J. Allison: Automotive Alloys III, TMS, Warrendale, PA, 1999.
C. Cloutier, J.W. Jones, and J.E. Allison: SAE Paper 2000-01-0759, SAE International, Warrendale, PA, 1998.
M. Militzer: Steel Res., vol. 69, pp. 279–85, 1998.
C. Wolverton, X.-Y. Yan, R. Vijayaraghavan, and V. Ozolins: Acta Mater., 2002, vol. 50, p. 2187.
J. Boileau, C. Cloutier, L. Godlewski, P. Reeber-Symanksi, C. Wolverton, and J.E. Allison: SAE Paper 2003-01-0822, SAE International, Warrendale, PA, 2003.
J.D. Boyd and R.B. Nicholson: Acta Metall., 1971, vol. 19, pp. 1379–91.
R. Sankaran and C. Laird: Acta Metall., 1974, vol. 22, pp. 957–69.
K.E. Rajab and R.D. Doherty: Acta Metall., 1989, vol. 37, pp. 2709–22.
K.T. Moore and J.M. Howe: Acta Mater., 2000, vol. 48, pp. 4083–98.
R. Jahn: Internal Report, Ford Motor Company, Dearborn, MI, 1999.
Y.H. Chen and R.D. Doherty: Scripta Metall., 1977, vol. 11, pp. 725–29.
H.I. Aaronson and C. Laird: Trans. TMS-AIME, 1968, vol. 242, pp. 1437–48.
R. Sankaran and C. Laird: Scripta Metall., 1977, vol. 11, pp. 383–86.
C. Wolverton and J.E. Allison: US Patent Application US20030127159 Al, 2003.
L.-Q. Chen, V. Vaithyanathan, C. Wolverton, and Z.-K. Liu: MRS Bull., 2000, vol. 26, p. 197.
V. Vaithyanathan, C. Wolverton, and L.-Q. Chen: Phys. Rev. Lett., 2002, vol. 88, pp. 1255031–1255034.
A.G. Khachaturyan: Theory of Structural Transformations in Solids, Wiley, New York, NY, 1983.
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Weakley-Bollin, S.C., Donlon, W., Donlon, W. et al. Modeling the age-hardening behavior of Al-Si-Cu alloys. Metall Mater Trans A 35, 2407–2418 (2004). https://doi.org/10.1007/s11661-006-0221-9
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DOI: https://doi.org/10.1007/s11661-006-0221-9