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The debonding and fracture of Si particles during the fatigue of a cast Al-Si alloy

Publication ,  Journal Article
Gall, K; Yang, N; Horstemeyer, M; McDowell, DL; Fan, J
Published in: Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
January 1, 1999

Constant-amplitude high-cycle fatigue tests (σmax = 133 MPa, σmax/σy = 0.55, and R = 0.1) were conducted on cylindrical samples machined from a cast A356-T6 aluminum plate: The fracture surface of the sample with the smallest fatigue-crack nucleating defect was examined using a scanning electron microscope (SEM). For low crack-tip driving forces (fatigue-crack growth rates of da/dN < 1 × 10-7 m/cycle), we discovered that a small semicircular surface fatigue crack propagated primarily through the Al-1 pct Si dendrite cells. The silicon particles in the eutectic remained intact and served as barriers at low fatigue-crack propagation rates. When the semicircular fatigue crack inevitably crossed the three-dimensional Al-Si eutectic network, it propagated primarily along the interface between the silicon particles and the Al-1 pct Si matrix. Furthermore, nearly all of the silicon particles were progressively debonded by the fatigue cracks propagating at low rates, with the exception of elongated particles with a major axis perpendicular to the crack plane, which were fractured. As the fatigue crack grew with a high crack-tip driving force (fatigue-crack growth rates of da/dN > 1 × 10-6 m/cycle), silicon particles ahead of the crack tip were fractured, and the crack subsequently propagated through the weakest distribution of prefractured particles in the Al-Si eutectic. Only small rounded silicon particles were observed to debond while the fatigue crack grew at high rates. Using fracture-surface markings and fracture mechanics, a macroscopic measure of the maximum critical driving force between particle debonding vs fracture during fatigue-crack growth was calculated to be approximately Kmaxtr ≈ 6.0 MPa√m for the present cast A356 alloy.

Duke Scholars

Published In

Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science

DOI

ISSN

1073-5623

Publication Date

January 1, 1999

Volume

30

Issue

12

Start / End Page

3079 / 3088

Related Subject Headings

  • Materials
  • 4017 Mechanical engineering
  • 4016 Materials engineering
  • 0913 Mechanical Engineering
  • 0912 Materials Engineering
  • 0306 Physical Chemistry (incl. Structural)
 

Citation

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Gall, K., Yang, N., Horstemeyer, M., McDowell, D. L., & Fan, J. (1999). The debonding and fracture of Si particles during the fatigue of a cast Al-Si alloy. Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science, 30(12), 3079–3088. https://doi.org/10.1007/s11661-999-0218-2
Gall, K., N. Yang, M. Horstemeyer, D. L. McDowell, and J. Fan. “The debonding and fracture of Si particles during the fatigue of a cast Al-Si alloy.” Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science 30, no. 12 (January 1, 1999): 3079–88. https://doi.org/10.1007/s11661-999-0218-2.
Gall K, Yang N, Horstemeyer M, McDowell DL, Fan J. The debonding and fracture of Si particles during the fatigue of a cast Al-Si alloy. Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science. 1999 Jan 1;30(12):3079–88.
Gall, K., et al. “The debonding and fracture of Si particles during the fatigue of a cast Al-Si alloy.” Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science, vol. 30, no. 12, Jan. 1999, pp. 3079–88. Scopus, doi:10.1007/s11661-999-0218-2.
Gall K, Yang N, Horstemeyer M, McDowell DL, Fan J. The debonding and fracture of Si particles during the fatigue of a cast Al-Si alloy. Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science. 1999 Jan 1;30(12):3079–3088.
Journal cover image

Published In

Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science

DOI

ISSN

1073-5623

Publication Date

January 1, 1999

Volume

30

Issue

12

Start / End Page

3079 / 3088

Related Subject Headings

  • Materials
  • 4017 Mechanical engineering
  • 4016 Materials engineering
  • 0913 Mechanical Engineering
  • 0912 Materials Engineering
  • 0306 Physical Chemistry (incl. Structural)