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Title: High-resolution electron microscopy studies of the precipitation of copper under neutron irradiation in an Fe-1.3WT % Cu alloy.

Abstract

We have studied by electron microscopy the copper-rich precipitates in an Fe-1.3wt%Cu model alloy irradiated with neutrons to doses of 8.61 x 10{sup {minus}3} dpa and 6.3 x 10{sup {minus}2} dpa at a temperature of {approximately}270 C. In the lower dose material a majority (ca. 60%)of the precipitates visible in high-resolution electron microscopy were timed 9R precipitates of size {approximately}2-4 nm, while ca. 40% were untwinned. In the higher dose material, a majority (ca. 75%) of visible precipitates were untwinned although many still seemed to have a 9R structure. The average angle {alpha} between the herring-bone fringes in the twin variants was measured as 125{degree}, not the 129{degree} characteristic of precipitates in thermally-aged and electron-irradiated material immediately after the bcc{r_arrow}9R martensitic transformation. We argue that these results imply that the bcc{r_arrow}9R transformation of small (<4 nm) precipitates under neutron irradiation takes place at the irradiation temperature of 270 C rather than after subsequent cooling. Preliminary measurements showed that precipitate sizes did not depend strongly on dose, with a mean diameter of 3.4 {+-} 0.7 nm for the lower dose material, and 3.0 {+-} 0.5 nm for the higher dose material. This result agrees with the previous assumption that the lackmore » of coarsening in precipitates formed under neutron irradiation is a consequence of the partial dissolution of larger precipitates by high-energy cascades.« less

Authors:
Publication Date:
Research Org.:
Argonne National Lab., IL (US)
Sponsoring Org.:
US Department of Energy (US)
OSTI Identifier:
10850
Report Number(s):
ANL/MSD/CP-96674
TRN: US0103881
DOE Contract Number:  
W-31109-ENG-38
Resource Type:
Conference
Resource Relation:
Conference: Materials Research Society, Boston, MA (US), 11/30/1998--12/04/1998; Other Information: PBD: 21 Dec 1998
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; IRON BASE ALLOYS; COPPER ALLOYS; DISSOLUTION; ELECTRON MICROSCOPY; IRRADIATION; NEUTRONS; PRECIPITATION; PHASE TRANSFORMATIONS; RADIATION EFFECTS

Citation Formats

Nicol, A C. High-resolution electron microscopy studies of the precipitation of copper under neutron irradiation in an Fe-1.3WT % Cu alloy.. United States: N. p., 1998. Web.
Nicol, A C. High-resolution electron microscopy studies of the precipitation of copper under neutron irradiation in an Fe-1.3WT % Cu alloy.. United States.
Nicol, A C. Mon . "High-resolution electron microscopy studies of the precipitation of copper under neutron irradiation in an Fe-1.3WT % Cu alloy.". United States. https://www.osti.gov/servlets/purl/10850.
@article{osti_10850,
title = {High-resolution electron microscopy studies of the precipitation of copper under neutron irradiation in an Fe-1.3WT % Cu alloy.},
author = {Nicol, A C},
abstractNote = {We have studied by electron microscopy the copper-rich precipitates in an Fe-1.3wt%Cu model alloy irradiated with neutrons to doses of 8.61 x 10{sup {minus}3} dpa and 6.3 x 10{sup {minus}2} dpa at a temperature of {approximately}270 C. In the lower dose material a majority (ca. 60%)of the precipitates visible in high-resolution electron microscopy were timed 9R precipitates of size {approximately}2-4 nm, while ca. 40% were untwinned. In the higher dose material, a majority (ca. 75%) of visible precipitates were untwinned although many still seemed to have a 9R structure. The average angle {alpha} between the herring-bone fringes in the twin variants was measured as 125{degree}, not the 129{degree} characteristic of precipitates in thermally-aged and electron-irradiated material immediately after the bcc{r_arrow}9R martensitic transformation. We argue that these results imply that the bcc{r_arrow}9R transformation of small (<4 nm) precipitates under neutron irradiation takes place at the irradiation temperature of 270 C rather than after subsequent cooling. Preliminary measurements showed that precipitate sizes did not depend strongly on dose, with a mean diameter of 3.4 {+-} 0.7 nm for the lower dose material, and 3.0 {+-} 0.5 nm for the higher dose material. This result agrees with the previous assumption that the lack of coarsening in precipitates formed under neutron irradiation is a consequence of the partial dissolution of larger precipitates by high-energy cascades.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1998},
month = {12}
}

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