Title: Phase transformation kinetics in rolled U-10 wt. % Mo foil: Effect of post-rolling heat treatment and prior γ-UMo grain size

Abstract

Here, the effect of sub-eutectoid heat treatment on the phase transformation behavior in rolled U-10 wt.% Mo (U10Mo) foils was systematically investigated. The as-cast 5 mm thick foils were initially homogenized at 900 °C for 48 h and were hot rolled to 2 mm and later cold rolled down to 0.2 mm. Three starting microstructures were evaluated: (i) hot + cold-rolled to 0.2 mm (as-rolled condition), (ii) hot + cold-rolled to 0.2 mm + annealed at 700 °C for 1 h, and (iii) hot + cold-rolled to 0.2 mm + annealed at 1000 °C for 60 h. Annealing of as-rolled materials at 700 °C resulted in small grain size (15 ± 9 μm average grain size), while annealing at 1000 °C led to very large grains (156 ± 118 μm average grain size) in rolled U10Mo foils. Later the samples were subjected to sub-eutectoid heat-treatment temperatures of 550 °C, 500 °C, and 400 °C for different durations of time starting from 1 h up to 100 h. U10Mo rolled foils went through various degrees of decomposition when subjected to the sub-eutectoid heat-treatment step and formed a lamellar microstructure through a cellular reaction mostly along the previous γ-UMo grain boundaries. Themore » least amount of cellular reaction was observed in the large-grain microstructure at all temperatures. Conversely, a substantial amount of cellular reaction was observed in both the as-rolled and the small-grain microstructure. After 100 h of heat treatment at 500 °C, the volume fraction of the lamellar phase was found to be 4%, 22%, and 82% in large-grain, as-rolled, and small-grain samples, respectively.« less

Authors:

Jana, Saumyadeep ^[1]; Overman, Nicole  ^[1];

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Varga, Tamas  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-5492-866X"
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Lavender, Curt ^[1]; Joshi, Vineet V. ^[1]

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1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

Publication Date:

2017-09-25

Research Org.:

Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

Sponsoring Org.:

USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Biological and Environmental Research (BER)

OSTI Identifier:

1395354

Alternate Identifier(s):

OSTI ID: 1549206

Report Number(s):

PNNL-SA-127108
Journal ID: ISSN 0022-3115; PII: S0022311517309170

Grant/Contract Number:  

AC05-76RL01830

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Nuclear Materials

Additional Journal Information:

Journal Volume: 496; Journal Issue: C; Journal ID: ISSN 0022-3115

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS