Abstract
A unified model has been developed for combined gas- and shrinkage-induced pore formation during solidification of metal alloys. The model is based on a pore-centric approach, in which the temporal evolution of the pore radius is calculated as a function of cooling rate, thermal gradient, gas diffusion, and shrinkage. It accounts for the effect of porosity formation on the liquid velocity within the mushy zone. Simulations for an aluminum alloy show that the porosity transitions smoothly from shrinkage-induced to gas-induced as the Niyama value is increased. A Blake (cavitation) instability is observed to occur when the porosity is both gas- and shrinkage-driven. A revised dimensionless Niyama curve for pure shrinkage is presented. The experimentally observed gas porosity trend that the pore volume decreases with increasing cooling rate is well predicted. The pore-centric formulation allows the present model to be solved locally, at any point in a casting, during a regular casting simulation.
Similar content being viewed by others
References
T.S. Piwonka and M.C. Flemings: Trans. AIME, 1966, vol. 236, pp. 1157–65.
K. Kubo and R.D. Pehlke: MTB, 1985, vol. 16, pp. 359-366.
A.S. Sabau and S. Viswanathan: Metall. Mater. Trans. B, 2002, vol. 33, pp. 243-255.
Ch. Pequet, M. Rappaz and M. Gremaud: Metall. Mater. Trans. A, 2002, vol. 33, pp. 2095–2106.
P.D. Lee and J.D. Hunt: Acta Mater., 1997, vol. 45, pp. 4155–4169.
R.C. Atwood, S. Sridhar, W. Zhang, and P.D. Lee: Acta Mater., 2000, vol. 48, pp. 405-417.
R.W. Hamilton, D. See, S. Butler, and P.D. Lee: Mater. Sci. Eng. A, 2003, vol. 343, pp. 290–300.
P.D. Lee and J.D. Hunt: Modeling of Casting, Welding, and Advanced Solidification Processes VII, TMS, Warrendale, PA, 1995, pp. 585–92.
P.D. Lee and J.D. Hunt: Scripta Mater., 1997, vol. 36, pp. 399-404.
R.C. Atwood and P. D. Lee: Metall. Mater. Trans. B, 2002, vol. 33, pp. 209-221.
P.D. Lee, A. Chirazi, and D. See: J. Light Met., 2001, vol. 1, pp. 15-30.
D. M. Stefanescu: Int. J. Cast Met. Res., 2005, vol. 18, pp. 129-143.
K.D. Carlson and C. Beckermann: Metall. Mater. Trans. A, 2009, vol. 40, pp. 163-175.
K.D. Carlson, Z. Lin, and C. Beckermann: Metall. Mater. Trans. B, 2007, vol. 38, pp. 541-555.
E. Niyama, T. Uchida, M. Morikawa, and S. Saito: AFS Int. Cast Met. J., 1982, vol. 7, pp. 52–63.
J. Guo, C. Beckermann, K.D. Carlson, D. Hirvo, K. Bell, T. Moreland, J. Gu, J. Clews, S. Scott, G. Couturier, and D. Backman: IOP Conference Series: Materials Science and Engineering, 2015, vol. 84, p. 012003.
L. Yao, S. Cockcroft, J. Zhu, and C. Reilly: Metall. Mater. Trans. A, 2011, vol. 42, pp. 4137-4148.
F.G. Blake: Acoustic Research Laboratory Harvard University, 1949, Technical Memoranda No. 12.
C.E. Brennen: Cavitation and Bubble Dynamics, Cambridge University Press, Cambridge, 2013.
D.M. Stefanescu and A.V. Catalina: Int. J. Cast Met. Res., 2011, vol. 24, pp. 144-150.
M. Felberbaum, E. Landry-Désy, L. Weber, and M. Rappaz: Acta Mater., 2011, vol. 59, pp. 2302-2308.
JMatPro, Sente Software Ltd., Surrey Technology Center, Surrey GU2 7YG, United Kingdom.
D. Emadi and J.E. Gruzleski: AFS Trans., 1994, vol. 102, pp. 307–12.
Q.T. Fang and D.A. Gragner: AFS Trans., 1989, vol. 97, pp. 989–1000.
Author information
Authors and Affiliations
Corresponding author
Additional information
Manuscript submitted June 20, 2016.
Rights and permissions
About this article
Cite this article
Khalajzadeh, V., Carlson, K.D., Backman, D.G. et al. A Pore-Centric Model for Combined Shrinkage and Gas Porosity in Alloy Solidification. Metall Mater Trans A 48, 1797–1816 (2017). https://doi.org/10.1007/s11661-016-3940-6
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11661-016-3940-6