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Title: Low temperature neutron irradiation effects on microstructure and tensile properties of molybdenum

Abstract

Polycrystalline molybdenum was irradiated in the hydraulic tube facility at the High Flux Isotope Reactor to doses ranging from 7.2 x 10{sup -5} to 0.28 dpa at {approx} 80 C. As-irradiated microstructure was characterized by room-temperature electrical resistivity measurements, transmission electron microscopy (TEM) and positron annihilation spectroscopy (PAS). Tensile tests were carried out between -50 and 100 C over the strain rate range 1 x 10{sup -5} to 1 x 10{sup -2} s{sup -1}. Fractography was performed by scanning electron microscopy (SEM), and the deformation microstructure was examined by TEM after tensile testing. Irradiation-induced defects became visible by TEM at {approx}0.001 dpa. Both their density and mean size increased with increasing dose. Submicroscopic three-dimensional cavities were detected by PAS even at {approx}0.0001 dpa. The cavity density increased with increasing dose, while their mean size and size distribution was relatively insensitive to neutron dose. It is suggested that the formation of visible dislocation loops was predominantly a nucleation and growth process, while in-cascade vacancy clustering may be significant in Mo. Neutron irradiation reduced the temperature and strain rate dependence of the yield stress, leading to radiation softening in Mo at lower doses. Irradiation had practically no influence on the magnitude andmore » the temperature and strain rate dependence of the plastic instability stress.« less

Authors:
 [1];  [2];  [1];  [1];  [1];  [1]
  1. ORNL
  2. Riso National Laboratory, Roskilde, Denmark
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); High Flux Isotope Reactor; Shared Research Equipment Collaborative Research Center
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
966082
DOE Contract Number:  
DE-AC05-00OR22725
Resource Type:
Journal Article
Journal Name:
Journal of Nuclear Materials
Additional Journal Information:
Journal Volume: 376; Journal Issue: 1; Journal ID: ISSN 0022-3115
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 22 GENERAL STUDIES OF NUCLEAR REACTORS; DEFECTS; DEFORMATION; DISLOCATIONS; ELECTRIC CONDUCTIVITY; FRACTOGRAPHY; HFIR REACTOR; HYDRAULICS; IRRADIATION; MICROSTRUCTURE; MOLYBDENUM; NEUTRONS; NUCLEATION; PLASTICS; POSITRONS; RADIATIONS; SCANNING ELECTRON MICROSCOPY; SPECTROSCOPY; STRAIN RATE; TENSILE PROPERTIES; TRANSMISSION ELECTRON MICROSCOPY

Citation Formats

Li, Meimei, Eldrup, M., Byun, Thak Sang, Hashimoto, Naoyuki, Snead, Lance Lewis, and Zinkle, Steven J. Low temperature neutron irradiation effects on microstructure and tensile properties of molybdenum. United States: N. p., 2008. Web. doi:10.1016/j.jnucmat.2007.12.001.
Li, Meimei, Eldrup, M., Byun, Thak Sang, Hashimoto, Naoyuki, Snead, Lance Lewis, & Zinkle, Steven J. Low temperature neutron irradiation effects on microstructure and tensile properties of molybdenum. United States. https://doi.org/10.1016/j.jnucmat.2007.12.001
Li, Meimei, Eldrup, M., Byun, Thak Sang, Hashimoto, Naoyuki, Snead, Lance Lewis, and Zinkle, Steven J. Tue . "Low temperature neutron irradiation effects on microstructure and tensile properties of molybdenum". United States. https://doi.org/10.1016/j.jnucmat.2007.12.001.
@article{osti_966082,
title = {Low temperature neutron irradiation effects on microstructure and tensile properties of molybdenum},
author = {Li, Meimei and Eldrup, M. and Byun, Thak Sang and Hashimoto, Naoyuki and Snead, Lance Lewis and Zinkle, Steven J},
abstractNote = {Polycrystalline molybdenum was irradiated in the hydraulic tube facility at the High Flux Isotope Reactor to doses ranging from 7.2 x 10{sup -5} to 0.28 dpa at {approx} 80 C. As-irradiated microstructure was characterized by room-temperature electrical resistivity measurements, transmission electron microscopy (TEM) and positron annihilation spectroscopy (PAS). Tensile tests were carried out between -50 and 100 C over the strain rate range 1 x 10{sup -5} to 1 x 10{sup -2} s{sup -1}. Fractography was performed by scanning electron microscopy (SEM), and the deformation microstructure was examined by TEM after tensile testing. Irradiation-induced defects became visible by TEM at {approx}0.001 dpa. Both their density and mean size increased with increasing dose. Submicroscopic three-dimensional cavities were detected by PAS even at {approx}0.0001 dpa. The cavity density increased with increasing dose, while their mean size and size distribution was relatively insensitive to neutron dose. It is suggested that the formation of visible dislocation loops was predominantly a nucleation and growth process, while in-cascade vacancy clustering may be significant in Mo. Neutron irradiation reduced the temperature and strain rate dependence of the yield stress, leading to radiation softening in Mo at lower doses. Irradiation had practically no influence on the magnitude and the temperature and strain rate dependence of the plastic instability stress.},
doi = {10.1016/j.jnucmat.2007.12.001},
url = {https://www.osti.gov/biblio/966082}, journal = {Journal of Nuclear Materials},
issn = {0022-3115},
number = 1,
volume = 376,
place = {United States},
year = {2008},
month = {1}
}