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Title: Temperature-dependent elastic anisotropy and mesoscale deformation in a nanostructured ferritic alloy

Journal Article · · Nature Communications
DOI:https://doi.org/10.1038/ncomms6178· OSTI ID:1159466
 [1];  [1];  [2];  [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS). Chemical and Engineering Materials Division
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS)

Nanostructured ferritic alloys (NFA) are a new class of ultrafine-grained oxide dispersion-strengthened steels, promising for service in extreme environments of high temperature and high irradiation in the next-generation of nuclear reactors. This is owing to the remarkable stability of their complex microstructures containing a high density of Y-Ti-O nanoclusters within grains and along the grain boundaries. While nanoclusters have been recognized to be the primary contributor to the exceptional resistance to irradiation and high-temperature creep, very little is known about the mechanical roles of the polycrystalline grains that constitute the bulk ferritic matrix. Here we report the mesoscale characterization of anisotropic responses of the ultrafine NFA grains to tensile stresses at various temperatures using the state-of-the-art in situ neutron diffraction. We show the first experimental determination of temperature-dependent single-crystal elastic constants for the NFA, and reveal a strong temperature-dependent elastic anisotropy due to a sharp decrease in the shear stiffness constant [c'=(c_11-c_12)/2] when a critical temperature ( T_c ) is approached, indicative of elastic softening and instability of the ferritic matrix. We also show, from anisotropy-induced intergranular strain/stress accumulations, that a common dislocation slip mechanism operates at the onset of yielding for low temperatures, while there is a deformation crossover from low-temperature lattice hardening to high temperature lattice softening in response to extensive plastic deformation.

Research Organization:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
Grant/Contract Number:
AC05-00OR22725
OSTI ID:
1159466
Journal Information:
Nature Communications, Vol. 5; ISSN 2041-1723
Publisher:
Nature Publishing GroupCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 40 works
Citation information provided by
Web of Science

References (43)

Effect of the α γ Phase Transition on the Stability of Dislocation Loops in bcc Iron journal April 2008
Elastic strain and stress determination by Rietveld refinement: generalized treatment for textured polycrystals for all Laue classes journal April 2001
Effect of Temperature on the Elastic Anisotropy of Pure Fe and Fe 0.9 Cr 0.1 Random Alloy journal November 2011
Influence of directional strength-to-stiffness on the elastic–plastic transition of fcc polycrystals under uniaxial tensile loading journal March 2010
Structural materials for fission & fusion energy journal November 2009
Self-consistent modelling of the plastic deformation of f.c.c. polycrystals and its implications for diffraction measurements of internal stresses journal May 1998
Temperature dependence of strengthening mechanisms in the nanostructured ferritic alloy 14YWT: Part II—Mechanistic models and predictions journal January 2013
First In Situ Lattice Strains Measurements Under Load at VULCAN journal October 2010
Temperature dependence of strengthening mechanisms in the nanostructured ferritic alloy 14YWT: Part I—Mechanical and microstructural observations journal January 2013
A calculation of elastic constants of ferromagnetic iron at finite temperatures journal January 1985
Dislocation pile-ups in Fe at high temperature journal May 2008
Phonon softening in ferromagnetic BCC iron journal October 1987
In situ generation of intergranular strains in an Al7050 alloy journal March 1998
Morphology, structure, and chemistry of nanoclusters in a mechanically alloyed nanostructured ferritic steel journal January 2012
Ultrafine-grained nanocluster-strengthened alloys with unusually high creep strength journal October 2009
On the diffractive determination of single-crystal elastic constants using polycrystalline samples journal September 2001
Influence of particle dispersions on the high-temperature strength of ferritic alloys journal August 2007
Advanced oxide dispersion strengthened and nanostructured ferritic alloys journal October 2013
Intergranular stresses in ZIRCALOY-2 journal March 2002
VULCAN—The engineering diffractometer at the SNS journal November 2006
Creep behavior and deformation mechanisms in a nanocluster strengthened ferritic steel journal February 2012
Measurement of single-crystal elastic constants by neutron diffraction from polycrystals journal August 1999
A model for calculating diffraction elastic constants journal February 2012
Poisson's ratio in cubic materials journal May 2006
Study of the deformation mechanisms in a Fe–14% Cr ODS alloy journal September 2012
Orientation-dependent evolution of the dislocation density in grain populations with different crystallographic orientations relative to the tensile axis in a polycrystalline aggregate of stainless steel journal March 2014
Intergranular stresses in Zircaloy-2 with rod texture journal January 1999
Diffraction elastic constants of a cubic polycrystal journal August 1997
Elastic anomalies in Fe–Cr alloys journal April 2013
Characterization of precipitates in MA/ODS ferritic alloys journal June 2006
Calculation of Single-Crystal Elastic Constants for Cubic Crystal Symmetry from Powder Diffraction Data journal December 1998
Vacancy Mechanism of High Oxygen Solubility and Nucleation of Stable Oxygen-Enriched Clusters in Fe journal November 2007
Vacancies as a constitutive element for the design of nanocluster-strengthened ferritic steels journal November 2008
Determination of the stress orientation distribution function using pulsed neutron sources journal January 2003
Elastic properties of polycrystals—influence of texture and stereology journal January 2000
Measured and predicted intergranular strains in textured austenitic steel journal January 2000
The anatomy of grain boundaries: Their structure and atomic-level solute distribution journal October 2013
Atomic structure of nanoclusters in oxide-dispersion-strengthened steels journal October 2011
Interphase and intergranular stress generation in carbon steels journal April 2004
Temperature dependence of the strength of fine- and ultrafine-grained materials journal February 2011
Introduction to the Characterization of Residual Stress by Neutron Diffraction book January 2005
Intergranular stresses in ZIRCALOY-2 journal March 2002
Strain-Function Method for the Direct Evaluation of Intergranular Strains and Stresses journal February 2000

Cited By (8)

Development of an oxide-dispersion-strengthened steel by introducing oxygen carrier compound into the melt aided by a general thermodynamic model journal December 2016
Line profile analysis of ODS steels Fe 20 Cr 5 AlTiY milled powders at different Y 2 O 3 concentrations journal April 2017
In situ measurements of reactions in a glass-forming batch by X-ray and neutron diffraction journal August 2018
Bending Behavior of a Wrought Magnesium Alloy Investigated by the In Situ Pinhole Neutron Diffraction Method journal August 2018
Characterization of Crystallographic Structures Using Bragg-Edge Neutron Imaging at the Spallation Neutron Source journal December 2017
Vacancy-controlled ultrastable nanoclusters in nanostructured ferritic alloys journal May 2015
Group precipitation and age hardening of nanostructured Fe-based alloys with ultra-high strengths journal February 2016
Microstructural and Mechanical-Property Manipulation through Rapid Dendrite Growth and Undercooling in an Fe-based Multinary Alloy journal August 2016

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