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Title: Discontinuous Precipitation in U-10 wt.%Mo Alloy: Reaction Kinetics, Effect of Prior gamma-UMo Microstructure, the Role of Grain-Boundary Misorientation, and the Effect of Ternary Alloying Addition

Abstract

Eutectoid transformation in U-10 wt.% Mo (U10Mo) alloy initiates through discontinuous precipitation (DP) resulting in the formation of a lamellar microstructure that consists of an a-U and Mo-enriched bcc ?-UMo phase along the prior ?-UMo grain boundaries. DP is the main mode of transformation at 500°C. However, continuous precipitation (CP) of ?’ U2Mo phase together with grain-boundary DP is observed at 400°C. The reaction kinetics are noted to be very sluggish at 400°C compared to 500°C. The degree of eutectoid transformation is related to the prior ?-UMo grain size, and a smaller average grain size leads to a larger amount of transformation at a given reaction temperature. Minor addition (0.2 wt.%) of a third alloying element (Cr, Ni, Co) leads to significant changes in the nature of the DP mechanism in U10Mo alloy. In addition, high-angle grain boundaries with a misorientation of 30–45° are observed to be the major DP initiation sites. The microstructural evolution of U10Mo alloy with regard to DP-based reaction is discussed.

Authors:
 [1];  [1]; ORCiD logo [1];  [1];  [1]; ORCiD logo [1]
  1. BATTELLE (PACIFIC NW LAB)
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1560620
Report Number(s):
PNNL-SA-141543
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
JOM. The Journal of the Minerals, Metals and Materials Society
Additional Journal Information:
Journal Volume: 71; Journal Issue: 8
Country of Publication:
United States
Language:
English

Citation Formats

Jana, Saumyadeep, Overman, Nicole R., Devaraj, Arun, Sweet, Lucas E., Lavender, Curt A., and Joshi, Vineet V. Discontinuous Precipitation in U-10 wt.%Mo Alloy: Reaction Kinetics, Effect of Prior gamma-UMo Microstructure, the Role of Grain-Boundary Misorientation, and the Effect of Ternary Alloying Addition. United States: N. p., 2019. Web. doi:10.1007/s11837-019-03588-4.
Jana, Saumyadeep, Overman, Nicole R., Devaraj, Arun, Sweet, Lucas E., Lavender, Curt A., & Joshi, Vineet V. Discontinuous Precipitation in U-10 wt.%Mo Alloy: Reaction Kinetics, Effect of Prior gamma-UMo Microstructure, the Role of Grain-Boundary Misorientation, and the Effect of Ternary Alloying Addition. United States. doi:10.1007/s11837-019-03588-4.
Jana, Saumyadeep, Overman, Nicole R., Devaraj, Arun, Sweet, Lucas E., Lavender, Curt A., and Joshi, Vineet V. Thu . "Discontinuous Precipitation in U-10 wt.%Mo Alloy: Reaction Kinetics, Effect of Prior gamma-UMo Microstructure, the Role of Grain-Boundary Misorientation, and the Effect of Ternary Alloying Addition". United States. doi:10.1007/s11837-019-03588-4.
@article{osti_1560620,
title = {Discontinuous Precipitation in U-10 wt.%Mo Alloy: Reaction Kinetics, Effect of Prior gamma-UMo Microstructure, the Role of Grain-Boundary Misorientation, and the Effect of Ternary Alloying Addition},
author = {Jana, Saumyadeep and Overman, Nicole R. and Devaraj, Arun and Sweet, Lucas E. and Lavender, Curt A. and Joshi, Vineet V.},
abstractNote = {Eutectoid transformation in U-10 wt.% Mo (U10Mo) alloy initiates through discontinuous precipitation (DP) resulting in the formation of a lamellar microstructure that consists of an a-U and Mo-enriched bcc ?-UMo phase along the prior ?-UMo grain boundaries. DP is the main mode of transformation at 500°C. However, continuous precipitation (CP) of ?’ U2Mo phase together with grain-boundary DP is observed at 400°C. The reaction kinetics are noted to be very sluggish at 400°C compared to 500°C. The degree of eutectoid transformation is related to the prior ?-UMo grain size, and a smaller average grain size leads to a larger amount of transformation at a given reaction temperature. Minor addition (0.2 wt.%) of a third alloying element (Cr, Ni, Co) leads to significant changes in the nature of the DP mechanism in U10Mo alloy. In addition, high-angle grain boundaries with a misorientation of 30–45° are observed to be the major DP initiation sites. The microstructural evolution of U10Mo alloy with regard to DP-based reaction is discussed.},
doi = {10.1007/s11837-019-03588-4},
journal = {JOM. The Journal of the Minerals, Metals and Materials Society},
number = 8,
volume = 71,
place = {United States},
year = {2019},
month = {8}
}

Works referenced in this record:

Development of very-high-density low-enriched-uranium fuels
journal, December 1997


Properties of DU–10wt% Mo alloys subjected to various post-rolling heat treatments
journal, June 2010


IRRADIATION PERFORMANCE OF U-Mo MONOLITHIC FUEL
journal, April 2014

  • Meyer, M. K.; Gan, J.; Jue, J. F.
  • Nuclear Engineering and Technology, Vol. 46, Issue 2
  • DOI: 10.5516/NET.07.2014.706

Calphad thermodynamic description of some binary systems involving U
journal, April 2011


The uranium-molybdenum equilibrium diagram below 900° C
journal, March 1960


Kinetics of cellular transformation and competing precipitation mechanisms during sub-eutectoid annealing of U10Mo alloys
journal, November 2017


Phase transformation of metastable discontinuous precipitation products to equilibrium phases in U10Mo alloys
journal, November 2018


Thermomechanical process optimization of U-10wt% Mo – Part 2: The effect of homogenization on the mechanical properties and microstructure
journal, October 2015


Thermomechanical process optimization of U-10 wt% Mo – Part 1: high-temperature compressive properties and microstructure
journal, October 2015


Fabrication of Monolithic RERTR Fuels by Hot Isostatic Pressing
journal, November 2010

  • Jue, Jan-Fong; Park, Blair H.; Clark, Curtis R.
  • Nuclear Technology, Vol. 172, Issue 2
  • DOI: 10.13182/NT10-A10905

Grain boundary engineering to control the discontinuous precipitation in multicomponent U10Mo alloy
journal, June 2018


Ageing characteristics of the metastable gamma phase in U–9 wt.% Mo alloy: experimental observations and thermodynamic validation
journal, September 2015


Phase transformation of metastable cubic γ-phase in U–Mo alloys
journal, September 2010


α-Phase transformation kinetics of U – 8 wt% Mo established by in situ neutron diffraction
journal, August 2016


Neutron and hard X-ray diffraction studies of the isothermal transformation kinetics in the research reactor fuel candidate U–8 wt%Mo
journal, May 2016

  • Säubert, Steffen; Jungwirth, Rainer; Zweifel, Tobias
  • Journal of Applied Crystallography, Vol. 49, Issue 3
  • DOI: 10.1107/S1600576716005744

Phase transformation kinetics in rolled U-10 wt. % Mo foil: Effect of post-rolling heat treatment and prior γ-UMo grain size
journal, December 2017


Microstructural study of gamma phase stability in U–9wt.% Mo alloy
journal, March 2012


Study of decomposition and reactions with aluminum matrix of dispersed atomized U-10 wt% Mo alloy
journal, December 2002