Hydride-Phase Formation and its Influence on Fatigue Crack Propagation Behavior in a Zircaloy-4 Alloy
- 228 Downloads
The hydride-phase formation and its influence on the fatigue behavior of a Zircaloy-4 alloy charged with hydrogen gas are investigated. First, the microstructure and fatigue crack propagation rate of the alloy in the as-received condition are studied. Second, the formation and homogeneous distribution of the delta zirconium hydride in the bulk and its effect on the fatigue crack propagation rate are presented. The results show that in the presence of hydrides, the zirconium alloy exhibits reduced toughness and enhanced crack growth rates. Finally, the influence of a preexisting fatigue crack in the specimen and the subsequent hydride formation are examined. The residual lattice strain profile around the fatigue crack tip is measured using neutron diffraction. It is observed that the combined effects of residual strains and hydride precipitation on the fatigue behavior are more severe leading to propagation of the crack under near threshold loading.
E. Garlea acknowledges the support of the National Science Foundation (NSF) International Materials Institutes (IMI) Program (DMR-0231320) and the Tennessee Advanced Materials Laboratory Fellowship Program. E. Garlea is grateful to Drs. D.A. Smith and S.J. Randolph for valuable suggestions regarding the nickel sputtering. This work has benefited from the use of Lujan Neutron Scattering Center at LANSCE, which is funded by the Office of Basic Energy Sciences (Department of Energy). Los Alamos National Laboratory is operated by Los Alamos National Security LLC under DOE Contract De-AC52-06NA25396. EBSD analysis was conducted at the SHaRE User Facility, which is sponsored at Oak Ridge National Laboratory by the Division of Scientific User Facilities, Office of Science, U.S. Department of Energy.
- 3.E.C.W. Perryman: J. Br. Nucl. Energ Soc., 1978, vol. 17 (2), pp. 95–105.Google Scholar
- 11.S. Suresh: Fatigue of Materials, 2nd ed, Cambridge University Press, New York, NY. 1998.Google Scholar
- 17.Wah Chang Company Technical Department, www.wahchang.com, 2010.
- 18.ASTM E647-86, Annual Book of ASTM Standards, 1986, pp. 714–36.Google Scholar
- 20.G.F.V. Voort: Metallography, Principles and Practice, ASM, Materials Park, OH, 1984, p. 701.Google Scholar
- 21.ASTM B 811, “Standard Specification for Wrought Zirconium Alloy Seamless Tubes for Nuclear Reactor Fuel Cladding”, 2007, p. 6.Google Scholar
- 22.H. Tada, P.C. Paris, and G.R. Irwin: The Stress Analysis of Cracks Handbook, Paris Productions, St. Louis, MO, 1985.Google Scholar
- 27.A.C. Larson and R.B. Von Dreele: General Structure Analysis System (GSAS), Los Alamos National Laboratory Report LAUR, http://www.ncnr.nist.gov/xtal/software/gsas.html, 2000, pp. 86–748.
- 28.ImageJ software: http://rsb.info.nih.gov/ij/.
- 29.ASTM E 562, “Standard Test Method for Determining Volume Fraction by Systematic Manual Point Count”, 2002.Google Scholar
- 36.R.W. Hertzberg: Deformation and Fracture Mechanics of Engineering Materials, 4th ed., Wiley, New York, NY, 1996, pp. 591–686.Google Scholar
- 42.W.S. Gorsky: Phys. Zeitschr. Sowjetunion, 1935, vol. 8, pp. 457.Google Scholar