skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Quantifying the stress fields due to a delta-hydride precipitate in alpha-Zr matrix

Abstract

This report is a preliminary study on δ-hydride precipitate in zirconium alloy performed using 3D discrete dislocation dynamics simulations. The ability of dislocations in modifying the largely anisotropic stress fields developed by the hydride particle in a matrix phase is addressed for a specific dimension of the hydride. The influential role of probable dislocation nucleation at the hydride-matrix interface is reported. Dislocation nucleation around a hydride was found to decrease the shear stress (S 13) and also increase the normal stresses inside the hydride. We derive conclusions on the formation of stacks of hydrides in zirconium alloys. The contribution of mechanical fields due to dislocations was found to have a non-negligible effect on such process.

Authors:
 [1];  [1];  [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE Office of Nuclear Energy (NE); USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1402569
Report Number(s):
LA-UR-17-29185
DOE Contract Number:
AC52-06NA25396
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE

Citation Formats

Tummala, Hareesh, Capolungo, Laurent, and Tome, Carlos N. Quantifying the stress fields due to a delta-hydride precipitate in alpha-Zr matrix. United States: N. p., 2017. Web. doi:10.2172/1402569.
Tummala, Hareesh, Capolungo, Laurent, & Tome, Carlos N. Quantifying the stress fields due to a delta-hydride precipitate in alpha-Zr matrix. United States. doi:10.2172/1402569.
Tummala, Hareesh, Capolungo, Laurent, and Tome, Carlos N. 2017. "Quantifying the stress fields due to a delta-hydride precipitate in alpha-Zr matrix". United States. doi:10.2172/1402569. https://www.osti.gov/servlets/purl/1402569.
@article{osti_1402569,
title = {Quantifying the stress fields due to a delta-hydride precipitate in alpha-Zr matrix},
author = {Tummala, Hareesh and Capolungo, Laurent and Tome, Carlos N.},
abstractNote = {This report is a preliminary study on δ-hydride precipitate in zirconium alloy performed using 3D discrete dislocation dynamics simulations. The ability of dislocations in modifying the largely anisotropic stress fields developed by the hydride particle in a matrix phase is addressed for a specific dimension of the hydride. The influential role of probable dislocation nucleation at the hydride-matrix interface is reported. Dislocation nucleation around a hydride was found to decrease the shear stress (S13) and also increase the normal stresses inside the hydride. We derive conclusions on the formation of stacks of hydrides in zirconium alloys. The contribution of mechanical fields due to dislocations was found to have a non-negligible effect on such process.},
doi = {10.2172/1402569},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2017,
month =
}

Technical Report:

Save / Share:
  • Sub-size impact specimens of annealed and cold-worked Zircaloy-2 were irradiated at 220 deg C with 3.6 x 10/sup 19/ n/cm/sup 2/, at 280 deg C with 2.7 x 10/sup 20/ n/cm/sup 2/, and then tested. It was found that the irradiation had very little effect on the impact properties of either the cold-worked or the annealed material. Results are given on the effect of a hydride precipitate on the impact properties of unirradiated material. Hydride layers approximately 10 mu m thick were deposited electrolytically on annealed Zircaloy-2 impact specimens. The presence of the hydride layer did not effect the impactmore » properties. Drop weight tests were performed on specimens taken from annealed Zircaloy-2 plate. Catastrophic crack propagation occurred below --115 deg C for specimens containing 7-ppm hydrogen and below --80 deg C for those containing 30- ppm hydrogen. (auth)« less
  • We have measured and modeled the change in electrical resistivity due to partial transformation to the martensitic {alpha}{prime}-phase in a {delta}-phase Pu-Ga matrix. The primary objective is to relate the change in resistance, measured with a 4-probe technique during the transformation, to the volume fraction of the {alpha}{prime} phase created in the microstructure. Analysis by finite element methods suggests that considerable differences in the resistivity may be anticipated depending on the orientational and morphological configurations of the {alpha}{prime} particles. Finite element analysis of the computed resistance of an assembly of lenticular shaped particles indicates that series resistor or parallel resistormore » approximations are inaccurate and can lead to an underestimation of the predicted amount of {alpha}{prime} in the sample by 15% or more. Comparison of the resistivity of a simulated network of partially transformed grains or portions of grains suggests that a correction to the measured resistivity allows quantification of the amount of {alpha}{prime} phase in the microstructure with minimal consideration of how the {alpha}{prime} morphology may evolve. It is found that the average of the series and parallel resistor approximations provide the most accurate relationship between the measured resistivity and the amount of {alpha}{prime} phase. The methods described here are applicable to any evolving two-phase microstructure in which the resistance difference between the two phases is measurable.« less
  • The habit plane shift phenomenon of ..cap alpha..'' nitride (Fe/sub 16/N/sub 2/) precipitate in ..cap alpha..-Fe is discovered by TEM observation. The habit plane of ..cap alpha..'' precipitate shifts from (100) toward (102). The angular shift increases as the precipitate grows. Also, the angular shift increases as the aspect ratio of ..cap alpha..'' particle increased. This relation has been predicted by considering the finite thickness effect on Khachaturyan's elastic theory. The crystal structure of the habit shifted precipitate is found to be distorted from a tetragonal structure, the structure of the initial ..cap alpha..'' precipitate. The real morphology of ..capmore » alpha..'' precipitate at the early stage is revealed as a rosette pattern on (001) habit plane. The branches of the rosette point in <100> and <110> directions. The possible reasons for the rosette morphology are discussed.« less