"The path towards plasma facing components: A review of state-of-the-art in W-based refractory high-entropy alloys"
Caleb Hatler, Ishtiaque Robin, Hyosim Kim, Nathan Curtis, Bochuan Sun, Eda Aydogan, Saryu Fensin, Adrien Couet, Enrique Martinez, Dan Thoma, Osman El Atwani,
Current Opinion in Solid State and Materials Science
Vol. 34
2025
Link
Developing advanced materials for plasma-facing components (PFCs) in fusion reactors is a crucial aspect for achieving sustained energy production. Tungsten (W) − based refractory high-entropy alloys (RHEAs) have emerged as promising candidates due to their superior radiation tolerance and high-temperature strength. This review paper will focus on recent advancements in W-based RHEA research, with particular emphasis on: predictive modelling with machine learning (ML) to expedite the identification of optimal RHEA compositions; additive manufacturing (AM) techniques, highlighting their advantages for rapid prototyping and high-throughput multi-compositional sample production; mechanical properties relevant to PFC applications, including hardness, high-temperature strength, and ductility; and the radiation tolerance of W-based RHEAs under irradiated conditions. Finally, the key challenges and opportunities for future research, particularly the holistic analysis of candidate compositions as well as the role of radiation activation and oxidation are identified. This review aims to provide a comprehensive overview of W-based RHEAs for fusion applications and their potential to guide the development and validation of advanced refractory high entropy alloys. |
"Thermodynamic assessment of the quaternary WTaCrV refractory high entropy alloy as a means to guide experimental approaches" Mark Fedorov, Jan Wrobel, Duc Nguyen-Manh, Caleb Hatler, Matthew Vigil, Dan J. Thoma, Osman El-Atwani, Enrique Martinez, Bochuan Sun, [2025] Acta Materialia · DOI: 10.1016/j.actamat.2025.121435 | |
"Design kinetic parameters for improved resilience of materials under irradiation" Eda Aydogan, Jesper Byggmästar, Matheus A. Tunes, Osman El-Atwani, Enrique Martinez, Mohammadhossein Nahavandian, [2025] Materials & Design · DOI: 10.1016/j.matdes.2025.114419 | |
"Effect of alloying on intrinsic ductility in WTaCrV high entropy alloys" Osman El-Atwani, Enrique Martinez, Akshay Korpe, [2025] Materialia · DOI: 10.1016/j.mtla.2025.102519 | |
"Segregation, ordering, and precipitation in WTaV-based concentrated refractory alloys" Damian Sobieraj, Jan S. Wróbel, Daniel K. Schreiber, Osman El-Atwani, Enrique Martinez, Duc Nguyen-Manh, Jesper Byggmästar, [2025] Acta Materialia · DOI: 10.1016/j.actamat.2025.121276 | |
"Atomic Structure of the Lithium–Lithium Oxide Interface from First Principles" Jun Li, Steven D. Kenny, Enrique Martinez, Giovanni Orlandi, [2025] ACS Applied Materials & Interfaces · DOI: 10.1021/acsami.4c22106 | |
"Prediction of defect properties in concentrated solid solutions using a Langmuir-like model" Fadi Abdeljawad, Suveen Mathaudhu, Emmanuelle Marquis, Enrique Martinez, Jacob Jeffries, [2025] Physical Review Materials · DOI: 10.1103/physrevmaterials.9.033803 | |
"From anti-Arrhenius to Arrhenius behavior in a dislocation-obstacle bypass: Atomistic simulations and theoretical investigation" Soumit Sarkar, Soumendu Bagchi, Danny Perez, Enrique Martinez, Mohammadhossein Nahavandian, [2024] Computational Materials Science · DOI: 10.1016/j.commatsci.2024.112954 | |
"A novel route to fibers with volatile crystalline semiconductor cores part 2: Selenides and phosphides" Enrique Martinez, Thomas W. Hawkins, Colin McMillen, John Ballato, Thomasina Zaengle, [2023] Optical Materials · DOI: 10.1016/j.optmat.2023.114388 | |
"A combined kinetic Monte Carlo and phase field approach to model thermally activated dislocation motion" Nithin Mathew, Irene J. Beyerlein, Enrique Martinez, Abigail Hunter, Xiaoyao Peng, [2023] Computational Materials Science · DOI: 10.1016/j.commatsci.2023.112490 | |
"Impact of Soret effect on hydrogen and helium retention in PFC tungsten under ELM-like conditions"
Sophie Blondel, Enrique Martínez, Dimitrios Maroudas, Brian D. Wirth, Dwaipayan Dasgupta,
[2023]
Nuclear Fusion
· DOI: 10.1088/1741-4326/acda4a
In our previous work, we have demonstrated using nonequilibrium molecular-dynamics simulations that the fluxes of helium and self-interstitial atoms in the presence of a thermal gradient in tungsten are directed opposite to the heat flux, indicating that species transport is governed by a Soret effect, namely, thermal-gradient-driven diffusion, characterized by a negative heat of transport that drives species transport uphill, i.e. from the cooler to the hot regions of the tungsten sample. In this work, the findings of our thermal and species transport analysis have been implemented in our cluster-dynamics code, Xolotl, which has been used to compute temperature and species profiles over spatiotemporal scales representative of plasma-facing component (PFC) tungsten under typical reactor operating conditions, including extreme heat loads at the plasma-facing surface characteristic of plasma instabilities that induce edge localized modes (ELMs). We demonstrate that the steady-state species profiles, when properly accounting for the Soret effect, vary significantly from those where temperature-gradient-driven transport is not accounted for and discuss the implications of such a Soret effect on the response to plasma exposure of plasma-facing tungsten. Although our cluster-dynamics simulations do not yet include self-clustering of helium or hydrogen blister formation, our simulation results show that the Soret effect substantially reduces helium and hydrogenic species retention inside PFC tungsten. |
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"Volume of a dislocation network" Sergei L. Dudarev, Daniel R. Mason, Enrique Martínez, Max Boleininger, [2022] Physical Review Materials · DOI: 10.1103/physrevmaterials.6.063601 | |
"Interaction of transmutation products with precipitates, dislocations and grain boundaries in neutron irradiated W" A.J. London, J.C. Haley, M.R. Gilbert, C.S. Becquart, C. Domain, E. Martinez, M.P. Moody, P.A.J. Bagot, D. Nguyen-Manh, D.E.J. Armstrong, M.J. Lloyd, [2022] Materialia · DOI: 10.1016/j.mtla.2022.101370 | |
"Influence of stress correlations on dislocation glide in random alloys" Enrique Martinez, David Rodney, Pierre-Antoine Geslin, Ali Rida, [2022] Physical Review Materials · DOI: 10.1103/physrevmaterials.6.033605 | |
"Thermal gradient effect on helium and self-interstitial transport in tungsten"
Nithin Mathew, Danny Perez, Sophie Blondel, Dwaipayan Dasgupta, Brian D. Wirth, Dimitrios Maroudas, Enrique Martínez,
[2021]
Journal of Applied Physics
· DOI: 10.1063/5.0071935
First-wall materials in a fusion reactor are expected to withstand harsh conditions, with high heat and particle fluxes that modify the materials microstructure. These fluxes will create strong gradients of temperature and concentration of diverse species. Besides the He ash and the hydrogenic species, neutron particles generated in the fusion reaction will collide with the material creating intrinsic defects, such as vacancies, self-interstitials atoms (SIAs), and clusters of such point defects. These defects and the He atoms will then migrate in the presence of the aforementioned gradients. In this study, we use nonequilibrium molecular dynamics to analyze the transport of He and SIAs in the presence of a thermal gradient in tungsten. We observe that, in all cases, the defects and impurity atoms tend to migrate toward the hot regions of the tungsten sample. The resulting species concentration profiles are exponential distributions, rising toward the hot regions of the sample, in agreement with irreversible thermodynamics analysis. For both He atoms and SIAs, we find that the resulting species flux is directed opposite to the heat flux, indicating that species transport is governed by a Soret effect (thermal-gradient-driven diffusion) characterized by a negative heat of transport that drives species diffusion uphill (from the cooler to the hot regions of the sample). We demonstrate that the steady-state species profiles obtained accounting for the Soret effect vary significantly from those where temperature-gradient-driven transport is not considered and discuss the implications of such a Soret effect on the response to plasma exposure of plasma-facing tungsten. |
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"Non-orthogonal computational grids for studying dislocation motion in phase field approaches" Abigail Hunter, Irene J. Beyerlein, Ricardo A. Lebensohn, Kaushik Dayal, Enrique Martinez, Xiaoyao Peng, [2021] Computational Materials Science · DOI: 10.1016/j.commatsci.2021.110834 | |
"Development of a solute and defect concentration dependant Ising model for the study of transmutation induced segregation in neutron irradiated W–(Re, Os) systems"
E Martinez, L Messina, D Nguyen-Manh, M J Lloyd,
[2021]
Journal of Physics: Condensed Matter
· DOI: 10.1088/1361-648x/ac1ec4
In this study, radiation-induced precipitation of transmutation products is addressed via the development of a new solute and vacancy concentration dependant Ising model for the W–Re–Os system. This new model includes interactions between both Os and Re atoms with vacancies, thus facilitating more representative simulations of transmutation in fusion reactor components. Local solute concentration dependencies are introduced for the W–Re, W–Os and Re–Os pair interactions. The model correctly accounts for the repulsion between small clusters of vacancies and the attraction between larger clusters/voids, via the introduction of local vacancy concentration dependant interaction coefficients between pairs of atoms and vacancies. To parameterise the pair interactions between atoms and/or vacancies, the enthalpy of mixing, Δ |
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"On the cross-slip of screw dislocations in zirconium" Sabyasachi Chatterjee, Enrique Martinez, Nasr Ghoniem, Giacomo Po, Yang Li, [2021] Acta Materialia · DOI: 10.1016/j.actamat.2021.116764 | |
"Prediction of the Al-rich part of the Al-Cu phase diagram using cluster expansion and statistical mechanics" E. Martínez, J. LLorca, S. Liu, [2020] Acta Materialia · DOI: 10.1016/j.actamat.2020.05.018 | |
"Reaction Rates in Nitromethane under High Pressure from Density Functional Tight Binding Molecular Dynamics Simulations" M. J. Cawkwell, Enrique Martinez, Shawn D. McGrane, Romain Perriot, [2020] The Journal of Physical Chemistry A · DOI: 10.1021/acs.jpca.9b11897 · ISSN: 1089-5639 | |
"Coherent phase decomposition in the Pd–H system" A. K. Khachaturyan, A. Caro, M. I. Baskes, E. Martinez, R. B. Schwarz, [2020] Journal of Materials Science · DOI: 10.1007/s10853-019-04179-z | |
"Influence of the stress state on the cross-slip free energy barrier in Al: An atomistic investigation" R. Santos-Güemes, I. Papadimitriou, E. Martínez, J. LLorca, G. Esteban-Manzanares, [2020] Acta Materialia · DOI: 10.1016/j.actamat.2019.10.055 | |
"Accelerated Molecular Dynamics Methods in a Massively Parallel World" D. Perez, E. Martinez, B. P. Uberuaga, A. F. Voter, R. J. Zamora, [2020] Handbook of Materials Modeling · DOI: 10.1007/978-3-319-42913-7_25-2 | |
"High irradiation resistance of nanocrystalline W-based high entropy alloy [Slides]" Enrique Saez, Nan Li, Jon Baldwin, Stuart Maloy, Meimei Li, Duc Nguyen, Damian Sobieraj, Jan Wrobel, Arun Devaraj, Osman El Atwani, [2019] · DOI: 10.2172/1573323 | |
"Parallel replica dynamics simulations of reactions in shock compressed liquid benzene"
R. Perriot, E. M. Kober, P. Bowlan, M. Powell, S. McGrane, M. J. Cawkwell, E. Martínez,
[2019]
The Journal of Chemical Physics
· DOI: 10.1063/1.5092209
· ISSN: 0021-9606
The study of the long-term evolution of slow chemical reactions is challenging because quantum-based reactive molecular dynamics simulation times are typically limited to hundreds of picoseconds. Here, the extended Lagrangian Born-Oppenheimer molecular dynamics formalism is used in conjunction with parallel replica dynamics to obtain an accurate tool to describe the long-term chemical dynamics of shock-compressed benzene. Langevin dynamics has been employed at different temperatures to calculate the first reaction times in liquid benzene at pressures and temperatures consistent with its unreacted Hugoniot. Our coupled engine runs for times on the order of nanoseconds (one to two orders of magnitude longer than traditional techniques) and is capable of detecting reactions that are characterized by rates significantly slower than we could study before. At lower pressures and temperatures, we mainly observe Diels-Alder metastable reactions, whereas at higher pressures and temperatures we observe stable polymerization reactions. |
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"α′ formation kinetics and radiation induced segregation in neutron irradiated 14YWT nanostructured ferritic alloys"
E. Martinez, K. March, O. El-Atwani, D. L. Krumwiede, P. Hosemann, T. Saleh, S. A. Maloy, E. Aydogan,
[2019]
Scientific Reports
· DOI: 10.1038/s41598-019-44508-5
Nanostructured ferritic alloys are considered as candidates for structural components in advanced nuclear reactors due to a high density of nano-oxides (NOs) and ultrafine grain sizes. However, bimodal grain size distribution results in inhomogeneous NO distribution, or vice versa. Here, we report that density of NOs in small grains (<0.5 µm) is high while there are almost no NOs inside the large grains (>2 µm) before and after irradiation. After 6 dpa neutron irradiation at 385–430 °C, α′ precipitation has been observed in these alloys; however, their size and number densities vary considerably in small and large grains. In this study, we have investigated the precipitation kinetics of α′ particles based on the sink density, using both transmission electron microscopy and kinetic Monte Carlo simulations. It has been found that in the presence of a low sink density, α′ particles form and grow faster due to the existence of a larger defect density in the matrix. On the other hand, while α′ particles form far away from the sink interface when the sink size is small, Cr starts to segregate at the sink interface with the increase in the sink size. Additionally, grain boundary characteristics are found to determine the radiation-induced segregation of Cr. |
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"Solute precipitation on a screw dislocation and its effects on dislocation mobility in bcc Fe" G. Monnet, G. Bonny, E. Martínez, J.J.H. Lim, M.G. Burke, L. Malerba, M.I. Pascuet, [2019] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2019.04.007 | |
"Probing ultrafast shock-induced chemistry in liquids using broad-band mid-infrared absorption spectroscopy"
Michael Powell, Romain Perriot, Enrique Martinez, Edward M. Kober, M. J. Cawkwell, Shawn McGrane, Pamela Bowlan,
[2019]
The Journal of Chemical Physics
· DOI: 10.1063/1.5092242
· ISSN: 0021-9606
We probe shock-induced chemistry in two organic liquids by measuring broadband, midinfrared absorption in the 800–1400 cm−1 frequency range. To test this new method and understand the signatures of chemical reactions in time resolved vibrational spectra, we compared liquid benzene shocked to unreactive conditions (shocked to a pressure of 18 GPa for a duration of 300 ps) to nitromethane under reactive conditions (25 GPa). We see clear signatures of shock-induced chemistry that are distinguishable from the pressure- and temperature-induced changes in vibrational mode shapes. While shocked benzene shows primarily a broadening and shifting of the vibrational modes, the nitromethane vibrational modes vanish once the shock wave enters the liquid and simultaneously, a spectrally broad feature appears that we interpret as the infrared spectrum of the complex mixture of product and intermediate species. To further interpret these measurements, we compare them to reactive quantum molecular dynamics simulations, which gives qualitatively consistent results. This work demonstrates a promising method for time resolving shock-induced chemistry, illustrating that chemical reactions produce distinct changes in the vibrational spectra. |
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"Dissociated vacancies and screw dislocations in MgO and UO2: atomistic modeling and linear elasticity analysis"
Enrique Martinez, Blas P. Uberuaga, Xiang-Yang Liu,
[2019]
Scientific Reports
· DOI: 10.1038/s41598-019-42926-z
Understanding the effect of dislocations on the mass transport in ionic ceramics is important for understanding the behavior of these materials in a variety of contexts. In particular, the dissociated nature of vacancies at screw dislocations, or more generally, at a wide range of low-angle twist grain-boundaries, has ramifications for the mechanism of defect migration and thus mass transport at these microstructural features. In this paper, a systematic study of the dissociated vacancies at screw dislocations in MgO is carried out. The important role of stress migration in the atomistic modeling study is identified. Another aspect of the current work is a rigorous treatment of the linear elasticity model. As a result, good agreement between the atomistic modeling results and the linear elasticity model is obtained. Furthermore, we demonstrate that the proposed vacancy dissociation mechanism can also be extended to more complicated ionic ceramics such as UO2, highlighting the generality of the mechanism. |
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"An atomistic investigation of the interaction of dislocations with Guinier-Preston zones in Al-Cu alloys" E. Martínez, J. Segurado, L. Capolungo, J. LLorca, G. Esteban-Manzanares, [2019] Acta Materialia · DOI: 10.1016/j.actamat.2018.09.052 | |
"Accelerated Molecular Dynamics Simulations of Shock-Induced Chemistry: Application to Liquid Benzene" E. M. Kober, M. J. Cawkwell, E. Martínez, [2019] Computational Approaches for Chemistry Under Extreme Conditions · DOI: 10.1007/978-3-030-05600-1_3 · ISSN: 2542-4491 | |
"The Kinetic Monte Carlo Algorithm in Materials Science: Study of Radiation-Induced Segregation in Fe-Cr alloys" Enrique Martinez Saez, [2018] · DOI: 10.2172/1475306 | |
"Loop and void damage during heavy ion irradiation on nanocrystalline and coarse grained tungsten: Microstructure, effect of dpa rate, temperature, and grain size" E. Esquivel, M. Efe, E. Aydogan, Y.Q. Wang, E. Martinez, S.A. Maloy, O. El-Atwani, [2018] Acta Materialia · DOI: 10.1016/j.actamat.2018.02.035 | |
"Structure and Mobility of Dissociated Vacancies at Twist Grain Boundaries and Screw Dislocations in Ionic Rocksalt Compounds" Enrique Martinez Saez, Blas Pedro Uberuaga, Kedarnath Kolluri, [2018] Chemistry of Materials · DOI: 10.1021/acs.chemmater.7b05172 | |
"Compositional and defect evolution under irradiation" Enrique Martinez Saez, [2018] · DOI: 10.2172/1422978 | |
"Advancing a phase field dislocation dynamics code to model HCP materials" Abigail Hunter, Irene Beyerlein, Enrique Martinez Saez, Curt Bronkhorst, Claire Weaver, [2017] · DOI: 10.2172/1392828 | |
"Effect of Li on the deformation mechanisms of nanocrystalline hexagonal close packed magnesium" N. Gupta, S. Groh, E. Martinez, A. Caro, S.G. Srinivasan, S. Karewar, [2017] Computational Materials Science · DOI: 10.1016/j.commatsci.2016.09.002 | |
"Atomistic modeling of the reordering process of γ′ disordered particles in Ni-Al alloys" Frédéric Soisson, Alfredo Caro, Blas P. Uberuaga, Enrique Martínez, [2016] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2016.06.019 | |
"Atomistic modeling of the reordering process of ?? disordered particles in Ni-Al alloys" Frédéric Soisson, Alfredo Caro, Blas P. Uberuaga, Enrique Martínez, [2016] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2016.06.019 | |
"Atomic-Scale Studies of Defect Interactions with Homo- and Heterophase Interfaces" Blas P. Uberuaga, Irene J. Beyerlein, Enrique Martínez, [2016] JOM · DOI: 10.1007/s11837-016-1887-0 | |
"Analytical model of the effect of misfit dislocation character on the bubble-to-void transition in metals" D. Schwen, J. Hetherly, A. Caro, Enrique Martínez, [2016] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2015.11.046 | |
"Atomistic Modelling of Segregation and Precipitation in Fe-Cr Alloys under Irradiation" Chu Chun Fu, Thomas Jourdan, Maylise Nastar, Oriane Senninger, Enrique Martinez, Yves Bréchet, Frédéric Soisson, [2016] EPJ Web of Conferences · DOI: 10.1051/epjconf/201611503002 | |
"Identification of dominant damage accumulation processes at grain boundaries during irradiation in nanocrystalline ?-Fe A statistical study" Rémi Dingreville, Enrique Martínez, Laurent Capolungo, Aaron Dunn, [2016] Acta Materialia · DOI: 10.1016/j.actamat.2016.03.026 | |
"Interaction of small mobile stacking fault tetrahedra with free surfaces, dislocations, and interfaces in Cu and Cu-Nb" Blas P. Uberuaga, Irene J. Beyerlein, Enrique Martínez, [2016] PHYSICAL REVIEW B · DOI: 10.1103/physrevb.93.054105 | |
"Modeling radiation induced segregation in iron-chromium alloys" Frédéric Soisson, Enrique Martínez, Maylise Nastar, Chu-Chun Fu, Yves Bréchet, Oriane Senninger, [2016] Acta Materialia · DOI: 10.1016/j.actamat.2015.09.058 | |
"Synchronous parallel spatially resolved stochastic cluster dynamics" Rémi Dingreville, Enrique Martínez, Laurent Capolungo, Aaron Dunn, [2016] Computational Materials Science · DOI: 10.1016/j.commatsci.2016.04.013 | |
"Thermostating extended Lagrangian Born-Oppenheimer molecular dynamics"
Marc J. Cawkwell, Arthur F. Voter, Anders M. N. Niklasson, Enrique Martínez,
[2015]
The Journal of Chemical Physics
· DOI: 10.1063/1.4917546
Extended Lagrangian Born-Oppenheimer molecular dynamics is developed and analyzed for applications in canonical (NVT) simulations. Three different approaches are considered: the Nosé and Andersen thermostats and Langevin dynamics. We have tested the temperature distribution under different conditions of self-consistent field (SCF) convergence and time step and compared the results to analytical predictions. We find that the simulations based on the extended Lagrangian Born-Oppenheimer framework provide accurate canonical distributions even under approximate SCF convergence, often requiring only a single diagonalization per time step, whereas regular Born-Oppenheimer formulations exhibit unphysical fluctuations unless a sufficiently high degree of convergence is reached at each time step. The thermostated extended Lagrangian framework thus offers an accurate approach to sample processes in the canonical ensemble at a fraction of the computational cost of regular Born-Oppenheimer molecular dynamics simulations. |
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"Helium segregation to screw and edge dislocations in ?-iron and their yield strength" Daniel Schwen, Alfredo Caro, Enrique Martínez, [2015] Acta Materialia · DOI: 10.1016/j.actamat.2014.10.066 | |
"Mobility and coalescence of stacking fault tetrahedra in Cu"
Blas P. Uberuaga, Enrique Martínez,
[2015]
SCIENTIFIC REPORTS
· DOI: 10.1038/srep09084
Stacking fault tetrahedra (SFTs) are ubiquitous defects in face-centered cubic metals. They are produced during cold work plastic deformation, quenching experiments or under irradiation. From a dislocation point of view, the SFTs are comprised of a set of stair-rod dislocations at the (110) edges of a tetrahedron bounding triangular stacking faults. These defects are extremely stable, increasing their energetic stability as they grow in size. At the sizes visible within transmission electron microscope they appear nearly immobile. Contrary to common belief, we show in this report, using a combination of molecular dynamics and temperature accelerated dynamics, how small SFTs can diffuse by temporarily disrupting their structure through activated thermal events. More over, we demonstrate that the diffusivity of defective SFTs is several orders of magnitude higher than perfect SFTs and can be even higher than isolated vacancies. Finally, we show how SFTs can coalesce, forming a larger defect in what is a new mechanism for the growth of these omnipresent defects. |
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"The capillarity equation at the nanoscale Gas bubbles in metals" D. Schwen, J. Hetherly, E. Martinez, A. Caro, [2015] ACTA MATERIALIA · DOI: 10.1016/j.actamat.2015.01.048 | |
"The relationship between grain boundary structure, defect mobility, and grain boundary sink efficiency"
Louis J. Vernon, Enrique Martinez, Arthur F. Voter, Blas Pedro Uberuaga,
[2015]
SCIENTIFIC REPORTS
· DOI: 10.1038/srep09095
Nanocrystalline materials have received great attention due to their potential for improved functionality and have been proposed for extreme environments where the interfaces are expected to promote radiation tolerance. However, the precise role of the interfaces in modifying defect behavior is unclear. Using long-time simulations methods, we determine the mobility of defects and defect clusters at grain boundaries in Cu. We find that mobilities vary significantly with boundary structure and cluster size, with larger clusters exhibiting reduced mobility and that interface sink efficiency depends on the kinetics of defects within the interface via the in-boundary annihilation rate of defects. Thus, sink efficiency is a strong function of defect mobility, which depends on boundary structure, a property that evolves with time. Further, defect mobility at boundaries can be slower than in the bulk, which has general implications for the properties of polycrystalline materials. Finally, we correlate defect energetics with the volumes of atomic sites at the boundary. |
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"Thermally Induced Interdiffusion and Precipitation in a Ni/Ni3Al System" E. Martínez, J.A. Aguiar, A. Caro, J.A. Valdez, K. Baldwin, Y. Xu, B.P. Uberuaga, O. Anderoglu, S.A. Maloy, C. Sun, [2015] MATERIALS RESEARCH LETTERS · DOI: 10.1080/21663831.2015.1045630 | |
"Atomistic modeling of defect-induced plasticity in CuNb nanocomposites" Alfredo Caro, Irene J. Beyerlein, Enrique Martínez, [2014] Physical Review B (Condensed Matter and Materials Physics) · DOI: 10.1103/physrevb.90.054103 | |
"Atomistic simulations of the decomposition kinetics in Fe-Cr alloys Influence of magnetism" Enrique Martínez, Frédéric Soisson, Maylise Nastar, Yves Bréchet, Oriane Senninger, [2014] Acta Materialia · DOI: 10.1016/j.actamat.2014.03.019 | |
"Radiation induced effects on mechanical properties of nanoporous gold foams"
W. M. Mook, E. G. Fu, Y. Q. Wang, C. Sheehan, E. Martinez, J. K. Baldwin, A. Caro, M. Caro,
[2014]
APPLIED PHYSICS LETTERS
· DOI: 10.1063/1.4882275
It has recently been shown that due to a high surface-to-volume ratio, nanoporous materials display radiation tolerance. The abundance of surfaces, which are perfect sinks for defects, and the relation between ligament size, defect diffusion, and time combine to define a window of radiation resistance [Fu et al., Appl. Phys. Lett. 101, 191607 (2012)]. Outside this window, the dominant defect created by irradiation in Au nanofoams are stacking fault tetrahedra (SFT). Molecular dynamics computer simulations of nanopillars, taken as the elemental constituent of foams, predict that SFTs act as dislocation sources inducing softening, in contrast to the usual behavior in bulk materials, where defects are obstacles to dislocation motion, producing hardening. In this work we test that prediction and answer the question whether irradiation actually hardens or softens a nanofam. Ne ion irradiations of gold nanofoams were performed at room temperature for a total dose up to 4 dpa, and their mechanical behavior was measured by nanoindentation. We find that hardness increases after irradiation, a result that we analyze in terms of the role of SFTs on the deformation mode of foams. |
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"Screw-dislocation constrictions in face-centered cubic crystals" John P. Hirth, Enrique Martínez, [2014] PHYSICAL REVIEW B · DOI: 10.1103/physrevb.90.064102 | |
"Sublattice parallel replica dynamics" Blas P. Uberuaga, Arthur F. Voter, Enrique Martínez, [2014] PHYSICAL REVIEW E · DOI: 10.1103/physreve.89.063308 | |
"A rate theory study of helium bubble formation and retention in Cu-Nb nanocomposites" M.G. McPhie, L. Capolungo, E. Martinez, M. Cherkaoui, A.Y. Dunn, [2013] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2012.12.041 | |
"Deformation mechanisms of irradiated metallic nanofoams"
E. Martinez, M. Caro, E. G. Fu, A. Caro, L. A. Zepeda-Ruiz,
[2013]
APPLIED PHYSICS LETTERS
· DOI: 10.1063/1.4813863
It was recently proposed that within a particular window in the parameter space of temperature, ion energy, dose rate, and filament diameter, nanoscale metallic foams could show radiation tolerance [Bringa et al., Nano Lett. 12, 3351 (2012)]. Outside this window, damage appears in the form of vacancy-related stacking fault tetrahedra (SFT), with no effects due to interstitials [Fu et al., Appl. Phys. Lett. 101, 191607 (2012)]. These SFT could be natural sources of dislocations within the ligaments composing the foam and determine their mechanical response. We employ molecular dynamics simulations of cylindrical ligaments containing an SFT to obtain an atomic-level picture of their deformation behavior under compression. We find that plastic deformation originates at the edges of the SFT, at lower stress than needed to create dislocations at the surface. Our results predict that nanoscale foams soften under irradiation, a prediction not yet tested experimentally. |
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"Liquid-phase Thermodynamics and Structures in the Cu-nb Binary System" Enrique Martinez, Alfredo Caro, Xiang-Yang Liu, Michael J Demkowicz, Liang Zhang, [2013] Modelling and Simulation in Materials Science and Engineering · DOI: 10.1088/0965-0393/21/2/025005 | |
"Nodal effects in alpha-iron dislocation mobility in the presence of helium bubbles" E. Martinez, B. K. Dutta, G. K. Dey, A. Caro, N. Naveen Kumar, [2013] PHYSICAL REVIEW B · DOI: 10.1103/physrevb.87.054106 | |
"On the analytic calculation of critical size for alpha prime precipitation in FeCr" E. Martinez, A. Caro, D. Schwen, [2013] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2013.03.057 | |
"Spatially resolved stochastic cluster dynamics for radiation damage evolution in nanostructured metals" Laurent Capolungo, Enrique Martinez, Mohammed Cherkaoui, Aaron Y. Dunn, [2013] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2013.07.009 | |
"Atomistic modeling of long-term evolution of twist boundaries under vacancy supersaturation" Alfredo Caro, Enrique Martínez, [2012] Physical Review B (Condensed Matter and Materials Physics) · DOI: 10.1103/physrevb.86.214109 | |
"Decomposition kinetics of Fe-Cr solid solutions during thermal aging" Oriane Senninger, Chu-Chun Fu, Frédéric Soisson, Enrique Martínez, [2012] Physical Review B (Condensed Matter and Materials Physics) · DOI: 10.1103/physrevb.86.224109 | |
"Scalable parallel Monte Carlo algorithm for atomistic simulations of precipitation in alloys" Paul Erhart, Alexander Stukowski, Alfredo Caro, Enrique Martinez, Luis Zepeda-Ruiz, Babak Sadigh, [2012] PHYSICAL REVIEW B · DOI: 10.1103/physrevb.85.184203 | |
"Structure of a 2 degrees (010) Cu twist boundary interface and the segregation of vacancies and He atoms" John P. Hirth, Michael Nastasi, Alfredo Caro, Enrique Martínez, [2012] PHYSICAL REVIEW B · DOI: 10.1103/physrevb.85.060101 | |
"Helium bubble growth at BCC twist grain boundaries" E. Martinez, M. Nastasi, A. Caro, J. Hetherly, [2011] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2011.08.009 | |
"Iron-chromium alloys and surfaces from ab initio calculations to segregation isotherms" E. Martinez, F. Soisson, C.C. Fu, M. Nastar, M. Levesque, [2011] REVUE DE METALLURGIE-CAHIERS D INFORMATIONS TECHNIQUES · DOI: 10.1051/metal/2011041 | |
"Properties of Helium bubbles in Fe and FeCr alloys" J. Hetherly, A. Stukowski, M. Caro, E. Martinez, S. Srivilliputhur, L. Zepeda-Ruiz, M. Nastasi, A. Caro, [2011] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2011.07.010 | |
Source: ORCID/CrossRef using DOI |
The Nuclear Science User Facilities (NSUF) is the U.S. Department of Energy Office of Nuclear Energy's only designated nuclear energy user facility. Through peer-reviewed proposal processes, the NSUF provides researchers access to neutron, ion, and gamma irradiations, post-irradiation examination and beamline capabilities at Idaho National Laboratory and a diverse mix of university, national laboratory and industry partner institutions.
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