Abstract
The effects of various microconstituents on crack initiation and propagation in high-cycle fatigue (HCF) were investigated in an aluminum casting alloy (A356.2). Fatigue cracking was induced in both axial and bending loading conditions at strain/stress ratios of −1, 0.1, and 0.2. The secondary dendrite arm spacing (SDAS) and porosity (maximum size and density distribution) were quantified in the directionally solidified casting alloy. Using scanning electron microscopy, we observed that cracks initiate at near-surface porosity, at oxides, and within the eutectic microconstituents, depending on the SDAS. When the SDAS is greater than ∼ 25 to 28 µm, the fatigue cracks initiate from surface and subsurface porosity. When the SDAS is less than ∼ 25 to 28 µm, the fatigue cracks initiate from the interdendritic eutectic constituents, where the silicon particles are segregated. Fatigue cracks initiated at oxide inclusions whenever they were near the surface, regardless of the SDAS. The fatigue life of a specimen whose crack initiated at a large eutectic constituent was about equal to that when the crack initiated at a pore or oxide of comparable size.
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R.E. Spear and G.R. Gardner: AFS Trans., 1960, vol. 68, pp. 36–44.
K. Radhakrishna, S. Seshan, and M.R. Seshadri: AFS Trans., 1980, vol. 88, pp. 695–702.
K.J. Oswalt and M.S. Misra: AFS Int. Cast Met. J., 1981, vol. 6, pp. 23–40.
J. Eady and D.M. Smith: Mater. Forum, 1986, vol. 9, pp. 217–23.
M.K. Surappa, E. Blank, and J.C. Jaquet: Scripta Metall., 1986, vol. 20, pp. 1281–86.
B. Closset and J.E. Gruzleski: Metall. Trans. A, 1982, vol. 13A, pp. 945–51.
G. Gustafsson, T. Thorvaldsson, and G.L. Dunlop: Metall. Trans. A, 1986, vol. 17A, pp. 45–52.
C.H. Caceres and J.R. Griffiths: Acta Mater., 1996, vol. 44, pp. 25–33.
Q.G. Wang and C.H. Caceres: Mater. Sci. Eng. A, 1998, vol. 241A, pp. 72–82.
D.L. Zhang and L. Zheng: Metall. Mater. Trans. A, 1996, vol. 27A, pp. 3983–91.
C.H. Caceres and Q.G. Wang: AFS Trans., 1996, vol. 104, pp. 1039–43.
W.A. Bailey: Foundry, 1965 (October), vol. 93 pp. 96–101.
J. Nath: SAE Technical Papers Series (SP-1097), No. 950723, SAE International, Warrendale, PA, 1995, pp. 75–90.
D. St John, C. Caceres, D. Zhang, and G. Edwards: Mater. Aust., 1996 (April), vol. 28, pp. 14–16.
C.Y. Kung and M.E. Fine: Metall. Trans. A, 1979, vol. 10A, pp. 603–10.
M.J. Couper, A.E. Neeson, and J.R. Griffiths: Fat. Fract. Eng. Mater. Struct., 1990, vol. 13, pp. 213–27.
J.C. Ting and F.V. Lawrence, Jr.: Fat. Fract. Eng. Mater. Struct., 1993, vol. 16, pp. 631–49.
S. Gungor and L. Edwards: Fat. Fract. Eng. Mater. Struct., 1993, vol. 16, pp. 391–403.
C.M. Sonsino and J. Ziese: Int. J. Fat., 1993, vol. 15, pp. 75–83.
J.H. Elsner, E.P. Kvam, and A.F. Grandt, Jr.: Metall. Mater. Trans. A, 1997, vol. 28A, pp. 1157–67.
P.C. Inguanti: Proc. 17th Nat. SAMPE Technical Conf., Kiamesha Lake, NY, Oct. 22–24, 1985, pp. 61–73.
J.M. Boileau, J.W. Zindel, and J.E. Allison: SAE Technical Papers Series (SP-1251), No. 970019, SAE International, Warrendale, PA, 1997, pp. 61–72.
W. Chen, B. Zhang, T. Wu, D.R. Poirier, P. Sung, and Q.T. Fang: in Automotive Alloys II, S.K. Das, ed., TMS, Warrendale, PA, 1998, pp. 99–113.
K. Shiozawa, Y. Tohda, and S.-M. Sun: Fat. Fract. Eng. Mater. Struct., 1997, vol. 20, pp. 237–47.
W. Chen, B. Zhang, and D.R. Poirier: The University of Arizona, Tucson, AZ unpublished research, 1998.
Q.T. Fang and D.A. Granger: in Light Metals 1989, P.G. Campbell, ed., TMS, Warrendale, PA, 1989, pp. 927–35.
Q.T. Fang and D.A. Granger: AFS Trans., 1989, vol. 97, pp. 989–1000.
“Standard Practice for Conducting Constant Amplitude Axial Fatigue Tests of Metallic Materials,” ASTM E466-82, Annual Book of ASTM Standards, ASTM, Philadelphia, PA, 1982, vol. 03.01, pp. 465–69.
K. Tynelius, J.F. Major, and D. Apelian: AFS Trans., 1993, vol. 101, pp. 401–13.
S. Shivkumar, L. Wang, and R. Lavigne: Light Metals 1993, S.K. Das, ed., TMS, Warrendale, PA, 1993, pp. 829–38.
H. Yokoyama, O. Umezawa, K. Nagai, and T. Suzuki: Iron Steel Inst. Jpn. Int., 1997, vol. 37, pp. 1237–44.
O. Umezawa and K. Nagai: Iron Steel Inst. Jpn. Int., 1997, vol. 37, pp. 1170–79.
M.E. Seniw, M.E. Fine, E.Y. Chen, M. Meshii, and J. Gray: in High Cycle Fatigue of Structural Materials, W.O. Soboyejo and T.S. Srivatsan, eds., TMS, Warrendale, PA, 1997, pp. 371–79.
J. Campbell, C. Nyahumwa, and N.R. Green: in Advances in Aluminum Casting Technology, M. Tiryakioglu and J. Campbell, eds., ASM INTERNATIONAL, Materials Park, OH, 1998, pp. 225–34.
Q.G. Wang, D. Apelian, and J.R. Griffiths: in Advances in Aluminum Casting Technology, M. Tiryakioglu and J. Campbell, eds., ASM INTERNATIONAL, Materials Park, OH, 1998, pp. 217–24.
F.T. Lee, J.F. Major, and F.H. Samuel: Metall. Mater. Trans. A, 1995, vol. 26A, pp. 1553–70.
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Zhang, B., Poirier, D.R. & Chen, W. Microstructural effects on high-cycle fatigue-crack initiation in A356.2 casting alloy. Metall Mater Trans A 30, 2659–2666 (1999). https://doi.org/10.1007/s11661-999-0306-3
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DOI: https://doi.org/10.1007/s11661-999-0306-3