ISSN: 1546-962X
CODEN: JAIOAD
Published Online: 24 April 2008
Page Count: 10

Application of Digital Marker Extensometry to Determine the True Stress-Strain Behavior of Irradiated Metals and Alloys

Gusev, M. N.
Institute of Nuclear Physics, Almaty,

Maksimkin, O. P.
Institute of Nuclear Physics, Almaty,

Osipov, I. S.
Institute of Nuclear Physics, Almaty,

Garner, F. A.
Pacific Northwest National Laboratory, Richland, Washington

(Received 4 April 2007; accepted 21 February 2008)

Abstract

To study the mechanisms of deformation hardening and flow localization of radioactive materials, a noncontact “digital marker extensometry” technique has been employed. It allows researchers to easily define plasticity parameters and true stresses in experiments where highly radioactive miniature specimens are used. The engineering and “true stress-true local strain” relationships of irradiated metal polycrystals during plastic flow and hardening have been investigated experimentally after irradiation in two reactors in Kazakhstan. The true curves were obtained for copper, nickel, iron, molybdenum, as well as for the Russian stainless steels 08Cr16Ni11Mo3 and 12Cr18Ni10Ti. Describing these curves using the equation σ_i =σ₀ + kε_i demonstrates that the concept of ultimate stress in highly irradiated materials is an artifact arising from flow localization and is not fully informative of the operating hardening mechanisms.

Keywords:
metals, alloys, neutron irradiation, extensometry, flow localization, tensile properties

Paper ID: JAI101073
DOI: 10.1520/JAI101073
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