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Title: PHASE STABILITY OF HIGHLY IRRADIATED AUSTENITIC ALLOYS DURING DEFORMATION

Authors:
 [1];  [1];  [1];  [1]
  1. ORNL
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). High Temperature Materials Lab. (HTML)
Sponsoring Org.:
USDOE
OSTI Identifier:
1132957
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Conference
Resource Relation:
Conference: Environmental Degradation of Materials in Nuclear Power Systems, Asheville, NC, USA, 20130811, 20130815
Country of Publication:
United States
Language:
English

Citation Formats

Gussev, Maxim N, Busby, Jeremy T, Byun, Thak Sang, and Tan, Lizhen. PHASE STABILITY OF HIGHLY IRRADIATED AUSTENITIC ALLOYS DURING DEFORMATION. United States: N. p., 2014. Web.
Gussev, Maxim N, Busby, Jeremy T, Byun, Thak Sang, & Tan, Lizhen. PHASE STABILITY OF HIGHLY IRRADIATED AUSTENITIC ALLOYS DURING DEFORMATION. United States.
Gussev, Maxim N, Busby, Jeremy T, Byun, Thak Sang, and Tan, Lizhen. Wed . "PHASE STABILITY OF HIGHLY IRRADIATED AUSTENITIC ALLOYS DURING DEFORMATION". United States. doi:.
@article{osti_1132957,
title = {PHASE STABILITY OF HIGHLY IRRADIATED AUSTENITIC ALLOYS DURING DEFORMATION},
author = {Gussev, Maxim N and Busby, Jeremy T and Byun, Thak Sang and Tan, Lizhen},
abstractNote = {},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Jan 01 00:00:00 EST 2014},
month = {Wed Jan 01 00:00:00 EST 2014}
}

Conference:
Other availability
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  • Recent studies have shown that significant compositional redistribution in irradiated alloys can be induced by the gradients in the atomic displacement rates resulting from nonuniform defect production, in addition to the commonly-observed solute segregation at defect sinks. This process gives rise to complex local phase transformations during light-ion bombardment or irradiation with focused electron beams in the high-voltage electron microscope. Results of our theoretical and experimental investigations of this phenomenon in Ni-Al and Ni-Si are discussed. The implications of the observed effect in a number of areas of materials science are assessed.
  • Two-phase {gamma}-tail alloys such as PM Ti-47Al-2Cr-2Nb or Ti-47Al- 2Cr-1Nb-Ta hot extruded above the {alpha}-transus temperature have unique refined-colony/ultrafine lamellar structures. These lamellar microstructures consist of very fine laths of the {gamma} and {alpha}{sub 2} phases, with average interlamellar spacings of 100 nm and {alpha}{sub 2}-{alpha}{sub 2} spacings of 200 nm, and are dominated by {gamma}/{alpha}{sub 2} interfaces. This ultrafine lamellar structure remains stable during 900 C heat treatment for 2 h, but becomes unstable after 4 h at 982 C. This structure remains stable in both alloys after aging for >5000 h at 800 C but disappears completely atmore » 1000 C. Continuous coarsening begins with dissolution of fine {alpha}{sub 2} lamellea. The aged Ta-modified alloy shows similar lamellar coarsening behavior within the colonies but has more discontinuous coarsening of the intercolony {gamma} with new precipitation of coarse {alpha}{sub 2} and {beta} phase particles. Analytical electron microscopy show that changes in {alpha}{sub 2} phase composition correlate with microstructural instability.« less
  • Microstructural evolution and deformation behavior of austenitic stainless steels are evaluated for neutron, heavy-ion and proton irradiated materials. Radiation hardening in austenitic stainless steels is shown to result from the evolution of small interstitial dislocation loops during light-water-reactor (LWR) irradiation. Available data on stainless steels irradiated under LWR conditions have been analyzed and microstructural characteristics assessed for the critical fluence range (0.5 too 10 dpa) where irradiation-assisted stress corrosion cracking susceptibility is observed. Heavy-ion and proton irradiations are used to produce similar defect microstructures enabling the investigation of hardening and deformation mechanisms. Scanning electron, atomic force and transmission electron microscopiesmore » are employed to examine tensile test strain rate and temperature effects on deformation characteristics. Dislocation loop microstructures are found to promote inhomogeneous planar deformation within the matrix and regularly spaced steps at the surface during plastic deformation. Twinning is the dominant deformation mechanism at rapid strain rates and at low temperatures, while dislocation channeling is favored at slower strain rates and at higher temperatures. Both mechanisms produce highly localized deformation and large surface slip steps. Channeling, in particular, is capable of creating extensive dislocation pileups and high stresses at internal grain boundaries which may promote intergranular cracking.« less