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Title: Grain boundary engineering to control the discontinuous precipitation in multicomponent U10Mo alloy

Here, we demonstrate here that locally stabilized structure and compositional segregation at grain boundaries in a complex multicomponent alloy can be modified using high temperature homogenization treatment to influence the kinetics of phase transformations initiating from grain boundaries during subsequent low temperature annealing. Using aberration-corrected scanning transmission electron microscopy and atom probe tomography of a model multicomponent metallic alloy —uranium-10 wt% molybdenum (U-10Mo) a nuclear fuel, that is highly relevant to worldwide nuclear non-proliferation efforts, we demonstrate the ability to change the structure and compositional segregation at grain boundary, which then controls the subsequent discontinuous precipitation kinetics during sub-eutectoid annealing. A change in grain boundary from one characterized by segregation of Mo and impurities at grain boundary to a phase boundary with a distinct U 2MoSi 2C wetting phase precipitates introducing Ni and Al rich interphase complexions caused a pronounced reduction in area fraction of subsequent discontinuous precipitation. The broader implication of this work is in highlighting the role of grain boundary structure and composition in metallic alloys on dictating the fate of grain boundary initiated phase transformations like discontinuous precipitation or cellular transformation. This work highlights a new pathway to tune the grain boundary structure and composition to tailormore » the final microstructure of multicomponent metallic alloys.« less
Authors:
ORCiD logo [1] ;  [2] ;  [1] ;  [3] ;  [4] ;  [4] ;  [4]
  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Physical and Computational Sciences Directorate
  2. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
  3. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Energy and Environmental Directorate
  4. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Energy and Environmental Directorate
Publication Date:
Report Number(s):
PNNL-SA-129167
Journal ID: ISSN 1359-6454; PII: S1359645418302374; TRN: US1802421
Grant/Contract Number:
AC05-76RL01830
Type:
Accepted Manuscript
Journal Name:
Acta Materialia
Additional Journal Information:
Journal Volume: 151; Journal Issue: C; Journal ID: ISSN 1359-6454
Publisher:
Elsevier
Research Org:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Grain boundaries; Grain boundary segregation; Microstructure; Phase transformation; Grain-boundary segregation-induced phase transformation
OSTI Identifier:
1432516

Devaraj, Arun, Kovarik, Libor, Kautz, Elizabeth, Arey, Bruce, Jana, Saumyadeep, Lavender, Curt, and Joshi, Vineet. Grain boundary engineering to control the discontinuous precipitation in multicomponent U10Mo alloy. United States: N. p., Web. doi:10.1016/j.actamat.2018.03.039.
Devaraj, Arun, Kovarik, Libor, Kautz, Elizabeth, Arey, Bruce, Jana, Saumyadeep, Lavender, Curt, & Joshi, Vineet. Grain boundary engineering to control the discontinuous precipitation in multicomponent U10Mo alloy. United States. doi:10.1016/j.actamat.2018.03.039.
Devaraj, Arun, Kovarik, Libor, Kautz, Elizabeth, Arey, Bruce, Jana, Saumyadeep, Lavender, Curt, and Joshi, Vineet. 2018. "Grain boundary engineering to control the discontinuous precipitation in multicomponent U10Mo alloy". United States. doi:10.1016/j.actamat.2018.03.039.
@article{osti_1432516,
title = {Grain boundary engineering to control the discontinuous precipitation in multicomponent U10Mo alloy},
author = {Devaraj, Arun and Kovarik, Libor and Kautz, Elizabeth and Arey, Bruce and Jana, Saumyadeep and Lavender, Curt and Joshi, Vineet},
abstractNote = {Here, we demonstrate here that locally stabilized structure and compositional segregation at grain boundaries in a complex multicomponent alloy can be modified using high temperature homogenization treatment to influence the kinetics of phase transformations initiating from grain boundaries during subsequent low temperature annealing. Using aberration-corrected scanning transmission electron microscopy and atom probe tomography of a model multicomponent metallic alloy —uranium-10 wt% molybdenum (U-10Mo) a nuclear fuel, that is highly relevant to worldwide nuclear non-proliferation efforts, we demonstrate the ability to change the structure and compositional segregation at grain boundary, which then controls the subsequent discontinuous precipitation kinetics during sub-eutectoid annealing. A change in grain boundary from one characterized by segregation of Mo and impurities at grain boundary to a phase boundary with a distinct U2MoSi2C wetting phase precipitates introducing Ni and Al rich interphase complexions caused a pronounced reduction in area fraction of subsequent discontinuous precipitation. The broader implication of this work is in highlighting the role of grain boundary structure and composition in metallic alloys on dictating the fate of grain boundary initiated phase transformations like discontinuous precipitation or cellular transformation. This work highlights a new pathway to tune the grain boundary structure and composition to tailor the final microstructure of multicomponent metallic alloys.},
doi = {10.1016/j.actamat.2018.03.039},
journal = {Acta Materialia},
number = C,
volume = 151,
place = {United States},
year = {2018},
month = {3}
}