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Title: Helium segregation to screw and edge dislocations in α-iron and their yield strength

Journal Article · · Acta Materialia
 [1];  [1];  [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
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Helium (He) introduces one of the mayor concerns in the nuclear materials community as it modifies the mechanical properties of the system withstanding fast neutron spectra, promoting swelling and embrittlement. Ferritic/martensitic steels are one of the main candidates as structural materials for future nuclear applications. Experimentally the bubble distribution is observed to vary depending on irradiation conditions (temperature, dose rate and total dose). However, traditional atomistic models decouple the role of temperature in the mechanical properties from its effect on the bubble distribution. In this paper we study substitutional He segregation to screw and edge dislocations in α-Fe at different temperatures. We use an object kinetic Monte Carlo methodology to obtain general trends in bubble distribution and a canonical Monte Carlo algorithm, with full atomistic fidelity, to find the He distribution at the dislocation cores. Molecular dynamics has subsequently been applied to study the yield strength, which increases significantly in the presence of He, more remarkably for the edge dislocation. The total stress fits a Kocks relation. Yet, if the lattice resistance is subtracted, the relation between the critical shear stress and the temperature is non-monotonic for the screw character. To reproduce this effect, we propose to modify the Kocks relation, adding a second-order term in temperature that extends the range of applicability of the model.

Research Organization:
Energy Frontier Research Centers (EFRC) (United States). Center for Materials at Irradiation and Mechanical Extremes (CMIME); Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Sponsoring Organization:
USDOE National Nuclear Security Administration (NNSA)
Grant/Contract Number:
2008LANL1026; AC52-06NA25396
OSTI ID:
1369955
Alternate ID(s):
OSTI ID: 1250968
Journal Information:
Acta Materialia, Vol. 84, Issue C; Related Information: CMIME partners with Los Alamos National Laboratory (lead); Carnegie Mellon University; University of Illinois, Urbana Champaign; Massachusetts Institute of Technology; University of Nebraska; ISSN 1359-6454
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 23 works
Citation information provided by
Web of Science

References (43)

On the potentiality of using ferritic/martensitic steels as structural materials for fusion reactors journal December 2003
High-Chromium Ferritic and Martensitic Steels for Nuclear Applications book January 2001
An integrated model for materials in a fusion power plant: transmutation, gas production, and helium embrittlement under neutron irradiation journal August 2012
Helium embrittlement in type 304 stainless steel journal February 1968
The influence of helium on the high temperature mechanical properties of DIN 1.4914 martensitic steel journal July 1988
Helium bubble precipitation at dislocation networks journal January 2012
Irradiation-tolerant nanostructured ferritic alloys: Transforming helium from a liability to an asset journal September 2010
Mechanisms controlling high temperature embrittlement due to helium journal January 1987
Helium in Metals: Effect on Mechanical Properties journal January 1992
Low temperature tensile properties of steels containing high concentrations of helium journal May 2003
The effect of cascade induced gas resolution on bubble formation in metals journal May 2003
Effect of implanted helium on tensile properties and hardness of 9% Cr martensitic stainless steels journal May 2003
On the effects of irradiation and helium on the yield stress changes and hardening and non-hardening embrittlement of ∼8Cr tempered martensitic steels: Compilation and analysis of existing data journal September 2006
Nodal effects in α -iron dislocation mobility in the presence of helium bubbles journal February 2013
A creep fracture model for irradiated and helium injected austenitic stainless steels journal January 1981
On the modeling of the high-temperature embrittlement of metals containing helium journal August 1983
The influence of helium on the bulk properties of fusion reactor structural materials journal August 1984
Effect of helium on irradiation-induced hardening of iron: A simulation point of view journal May 2007
Influence of the stress field due to pressurized nanometric He bubbles on the mobility of an edge dislocation in iron journal March 2010
Atomic-scale modeling of interactions of helium, vacancies and helium–vacancy clusters with screw dislocations in alpha-iron journal March 2010
Atomistic modeling of helium interacting with screw dislocations in α-Fe journal August 2007
Metals far from equilibrium: From shocks to radiation damage journal April 2003
Effects of temperature on the interactions of helium–vacancy clusters with gliding edge dislocations in α-Fe journal October 2013
Long time scale kinetic Monte Carlo simulations without lattice approximation and predefined event table journal December 2001
Growth mechanisms for TiO 2 at its rutile (110) surface journal February 2011
Kinetic activation-relaxation technique: An off-lattice self-learning kinetic Monte Carlo algorithm journal October 2008
Simulating complex atomistic processes: On-the-fly kinetic Monte Carlo scheme with selective active volumes journal October 2011
Atomistic modeling of long-term evolution of twist boundaries under vacancy supersaturation journal December 2012
Fast Parallel Algorithms for Short-Range Molecular Dynamics journal March 1995
Cr interactions with He and vacancies in dilute Fe-Cr alloys from first principles journal July 2011
A new interatomic potential function for helium journal January 1968
Pair potential for Fe–He journal December 2008
Properties of Helium bubbles in Fe and FeCr alloys journal November 2011
The vacancy–edge dislocation interaction in fcc metals: A comparison between atomic simulations and elasticity theory journal August 2006
An atomic-level model for studying the dynamics of edge dislocations in metals journal May 2003
Edge dislocation mobilities in bcc Fe obtained by molecular dynamics journal August 2011
The theory of an obstacle-controlled yield strength—Report after an international workshop journal March 1977
Stress and temperature dependence of screw dislocation mobility in α -Fe by molecular dynamics journal November 2011
Screw dislocation mobility in BCC Metals: a refined potential description for α-Fe journal August 2011
Quantum effect on thermally activated glide of dislocations journal August 2012
QM/MM study of dislocation—hydrogen/helium interactions in α-Fe journal July 2011
Anisotropic continuum theory of lattice defects journal January 1980
The strengthening effect of voids journal August 1982

Cited By (3)

Helium self-trapping and diffusion behaviors in deformed 316L stainless steel exposed to high flux and low energy helium plasma journal February 2018
Effects of Embedded Helium on the Microstructure and Mechanical Properties of Erbium Films journal November 2019
Helium bubble evolution and deformation of single crystal α-Fe journal September 2018

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36 MATERIALS SCIENCE
Helium
Segregation
Dislocation mobility
Modeling
Monte Carlo