Article
Materials Science, Multidisciplinary
Jia-Hong Ke, Benjamin W. Spencer
Summary: This study develops a new precipitation model that couples radiation-induced segregation with precipitation kinetics. The results show that segregation and heterogeneous nucleation play significant roles in the performance of nuclear structural materials under high neutron fluence.
JOURNAL OF NUCLEAR MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Huimin Zhang, Chengyuan Zhang, Zhongwang Wu, Xueyun Gao, Lei Xing, Zili Jin, Huiping Ren
Summary: Fe-3%Si-Cu alloys with different copper content were subjected to aging treatments at temperatures ranging from 500 to 800 degrees Celsius. The copper-rich precipitates gradually increased in size and amount with increasing aging time. The hardness of the alloys peaked at around 10^4.5 seconds when aged at 500 degrees Celsius, with a significant increase in precipitation tendency observed at higher copper contents. The precipitation kinetics curve of the alloys exhibited a 'C' shape, with a shorter incubation period observed at aging temperatures between 600 to 650 degrees Celsius.
MATERIALS RESEARCH EXPRESS
(2021)
Article
Nanoscience & Nanotechnology
Xueyun Gao, Haiyan Wang, Cainv Ma, Meng Lv, Gang Sha, Yiming Li, Huiping Ren
Summary: In this study, low carbon dual phase steels with ultrafine grains and nanoscale copper rich precipitates were produced by a combination of warm deformation and isothermal aging processes. The results indicate that the formation and compositional evolution of the Cu-rich particles are associated with the mixing enthalpy of alloying elements and the attractive interaction between the solute atoms.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Nanoscience & Nanotechnology
B. M. Jenkins, P. D. Styman, N. Riddle, P. A. J. Bagot, M. P. Moody, G. D. W. Smith, J. M. Hyde
Summary: Atom probe tomography was used to characterize two low-Cu model steels after long-term thermal aging, revealing Mn-Ni-Si-rich features forming as early as 20,731 hours of aging (approximately 2.4 years). The composition of these features was compared to thermodynamic models, discussing both similarities and differences.
SCRIPTA MATERIALIA
(2021)
Article
Materials Science, Multidisciplinary
Xuejiao Wang, Wenjiang Qiang, Guogang Shu, Junwei Qiao, Yucheng Wu
Summary: This paper studies the aging behavior of Cu-rich RPV model steels, finding that both hardness and coercivity exhibit aging peaks and there is a good correlation between them. The apparent activation energy of Cu-rich precipitations (CRPs) is estimated to be around 160 kJ·mol(-1).
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Rostyslav Nizinkovskyi, Thorsten Halle, Manja Krueger
Summary: This study develops a phase-field model to investigate the formation of elongated morphology of fcc-Cu precipitates in the bcc-Fe matrix. The results suggest that the influence of elastic properties and applied stress on the morphology formation is minor. Additionally, a bifurcation diagram of the interaction of two precipitates is constructed, revealing the role of elasticity in enhancing the kinetics of the reaction.
JOURNAL OF NUCLEAR MATERIALS
(2022)
Article
Chemistry, Physical
Z. G. Zheng, Y. B. Chen, J. Wei, X. Wang, Z. G. Qiu, D. C. Zeng
Summary: The effects of Fe content and annealing temperature on the microstructure, thermal stability, and soft magnetic properties of Fe-rich alloys were investigated. Increasing Fe content up to 85% allowed the formation of a single amorphous phase, but beyond that, crystalline phase appeared. Higher Fe content resulted in a larger crystallization temperature interval, contributing to the process of heat treatment and preparation of amorphous/nanocrystalline soft magnetic materials. The optimum annealing treatment at 430℃ for 10 minutes yielded a high saturation magnetization of 208 emu/g.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Chemistry, Physical
Munzali Musa, Xin Song, Xianglong Zhou, Wentao Jia, Tao Yuan, Tianyu Ma, Xiaobing Ren
Summary: Grain boundaries with sparse 1:5H precipitates are considered as the primary demagnetization sites in pinning-controlled 2:17-type Sm-Co-Fe-Cu-Zr permanent magnets, leading to poor magnetic properties. TEM investigations reveal that grain boundary regions contain larger 2:17R nanovariants, less SFs, and fewer defects-aggregated cell boundaries compared to grain interiors, indicating that early decomposition preferably occurs at grain boundaries.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Nanoscience & Nanotechnology
Xueyun Gao, Haiyan Wang, Lei Xing, Cainv Ma, Yiming Li, Gang Sha, Huiping Ren
Summary: The simultaneous improvement in strength and ductility of ferrite/martensite dual-phase (DP) steels was studied by investigating the synergistic effects of ultrafine grains and nano Cu-rich precipitates. Through experimental methods and simulations, it was found that a 75% reduction in warm deformation resulted in finer grains and higher tensile strength, with an optimal mechanical properties of yield strength of 876 +/- 13 MPa, tensile strength of 976 +/- 15 MPa, and total elongation of 15.2%. Additionally, the precipitation of nano Cu-rich precipitates contributed to an increase in strength of approximately 300 MPa.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Nanoscience & Nanotechnology
Xueyun Gao, Haiyan Wang, Lei Xing, Cainv Ma, Yiming Li, Gang Sha, Huiping Ren
Summary: The simultaneous improvement in strength and ductility of ferrite/martensite dual-phase (DP) steels was studied by investigating the synergistic effects of ultrafine grains and nano-size Cu-rich precipitates. It was found that a 75% reduction in warm deformation led to finer grains and higher tensile strength. Crystal plasticity (CP) simulations showed that the heterogeneous distribution of martensite resulted in strong strain and stress partitioning, facilitating early damage nucleation. The strengthening effect of precipitation from nano Cu-rich precipitates was also evaluated, contributing to an approximately 300 MPa increase in strength in the steels.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Materials Science, Multidisciplinary
Libang Lai, Paul Chekhonin, Shavkat Akhmadaliev, Jann-Erik Brandenburg, Frank Bergner, Andrii Kostryzhev
Summary: Ion irradiation is a promising tool for simulating neutron-irradiation effects on reactor pressure vessel (RPV) steels when neutron-irradiated materials are limited. This study compares the effects of ions and neutrons on the same materials and addresses the transferability issues between ions and neutrons. The first part of the study characterizes unirradiated RPV materials using electron microscopy techniques, while the second part focuses on the depth-dependent characterization of dislocation loops formed in ion-irradiated samples. Ion irradiation creates similar loop sizes but higher loop densities compared to neutron irradiation, possibly due to the higher dose rate.
Article
Materials Science, Multidisciplinary
Qigui Yang, Par Olsson
Summary: Understanding the formation and evolution of Cu precipitates in Fe-based alloys is crucial for their hardening and embrittlement effects. This study presents a first-principles investigation of positron annihilation in Fe-Cu systems, accurately predicting the characteristics of various homogeneous and heterogeneous Cu precipitates. The theoretical results show excellent agreement with experimental data, enabling clear distinction of different Cu precipitate types and reasonable estimation of their sizes. This work enhances the understanding of early-stage Cu precipitation in Fe matrix.
Article
Materials Science, Multidisciplinary
Huimin Zhang, Chengyuan Zhang, Zhongwang Wu, Huiping Ren, Zili Jin, Lei Xing
Summary: This paper proposes a new composition system of grain-oriented electrical steel with Cu-rich precipitates as the main inhibitor to overcome the bottleneck of high energy consumption in traditional grain-oriented electrical steel production. The research analyzes the microstructure, texture, precipitates, and decarburization effect of primary recrystallization samples during decarburization annealing treatment at different temperatures and times. The results show that annealing temperature significantly affects the decarburization effect, with the best effect at 850 degrees C. The optimal process is decarburization annealing at 850 degrees C for 6 minutes, reducing the carbon content to less than 40 ppm and achieving a good inhibiting effect with Cu-rich precipitates.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2022)
Article
Materials Science, Multidisciplinary
M. Harwarth, G. Chen, R. Rahimi, H. Biermann, A. Zargaran, M. Duffy, M. Zupan, J. Mola
Summary: The age hardenability of Al-alloyed lightweight stainless steels with different Ni concentrations was studied, showing significant impact on microstructures and hardening response. Hardness measurements indicated significant hardening at 350 degrees Celsius, while tensile elongation in the aged condition was negatively influenced by soft ferrite regions. Guidelines for the development of a new family of lightweight precipitation-hardenable steels were provided.
MATERIALS & DESIGN
(2021)
Article
Chemistry, Physical
Yu-chen Liu, Henry Wu, Tam Mayeshiba, Benjamin Afflerbach, Ryan Jacobs, Josh Perry, Jerit George, Josh Cordell, Jinyu Xia, Hao Yuan, Aren Lorenson, Haotian Wu, Matthew Parker, Fenil Doshi, Alexander Politowicz, Linda Xiao, Dane Morgan, Peter Wells, Nathan Almirall, Takuya Yamamoto, G. Robert Odette
Summary: This study demonstrates the potential benefits and risks of using machine learning models to predict irradiation hardening in LWR pressure vessel steels. By training the model and successful extrapolations, machine learning models can capture key intermediate flux effects at high fluence.
NPJ COMPUTATIONAL MATERIALS
(2022)
Article
Chemistry, Physical
Benjamin T. Afflerbach, Carter Francis, Lane E. Schultz, Janine Spethson, Vanessa Meschke, Elliot Strand, Logan Ward, John H. Perepezko, Dan Thoma, Paul M. Voyles, Izabela Szlufarska, Dane Morgan
Summary: In this study, a random forest model was used to predict the critical cooling rate for glass formation of different alloys based on features of their constituent elements. The model was trained on a comprehensive database and achieved high accuracy in cross-validation. It can be used to identify potential new metallic glass systems, but its main utility lies in identifying alloy systems with good glass formers.
CHEMISTRY OF MATERIALS
(2022)
Article
Chemistry, Physical
Juan Tapia-P, Yipeng Cao, Jaime Gallego, Jorge M. Osorio-Guillen, Dane Morgan, Juan F. Espinal
Summary: The intrinsic defects of LaMnO3 and their effects on CO catalytic properties were studied. The most stable surface under reaction conditions was determined through calculations. The adsorption energies and the influence of intrinsic defects were also calculated, showing that O vacancies promote the interaction of CO on the surface while Mn vacancies favor the formation of carbonate species.
Article
Materials Science, Multidisciplinary
Ajay Annamareddy, Manel Molina-Ruiz, Donez Horton-Bailey, Frances Hellman, Yuhui Li, Lian Yu, Dane Morgan
Summary: In this study, molecular dynamics simulations were used to investigate surface enhanced diffusion in (PbO)(x)(SiO2)(1-x) glasses. The results show that the addition of PbO to silica increases the fragility of the glass, which is correlated with enhanced surface diffusion. However, the enhancement of surface diffusion is relatively small compared to bulk diffusion, indicating minimal changes in atomic arrangements at the glass surface.
COMPUTATIONAL MATERIALS SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
Jingrui Wei, Ben Blaiszik, Aristana Scourtas, Dane Morgan, Paul M. Voyles
Summary: The information content of atomic-resolution STEM images can be summarized by a few parameters, with column position being the most significant. Neural networks have been used to automatically locate atomic columns in STEM images, resulting in numerous NN models and training datasets. In this study, a benchmark dataset of simulated and experimental STEM images was developed to evaluate the performance of recent NN models for atom location. The models showed high performance for images of varying quality and crystal lattices. However, they performed poorly for images outside the training data, such as interfaces with large difference in background intensity. The benchmark dataset and models are available through the Foundry service.
MICROSCOPY AND MICROANALYSIS
(2023)
Article
Chemistry, Multidisciplinary
Jun Meng, Mehrdad Abbasi, Yutao Dong, Corey Carlos, Xudong Wang, Jinwoo Hwang, Dane Morgan
Summary: This study characterized the structural and electronic properties of a-TiO2 thin films grown on Si by ALD, revealing the medium-range ordering in the film and establishing a realistic atomic model. Additionally, an improved multi-objective optimization package, StructOpt, was provided for structure determination of complex materials.
Article
Nanoscience & Nanotechnology
Mehrdad Abbasi, Yutao Dong, Jun Meng, Dane Morgan, Xudong Wang, Jinwoo Hwang
Summary: The evolution of medium range ordering (MRO) and crystallization behavior of amorphous TiO2 films grown by atomic layer deposition were investigated using in situ four-dimensional scanning transmission electron microscopy. The degree of MRO increases with temperature and reaches the maximum when crystallization starts to occur. In addition, post-annealing only develops a small portion of MRO into crystal nuclei, while the remaining MRO regions undergo structural relaxation. Crystallographic defects within crystal phases were observed, which may affect the corrosion resistance of the film. Understanding and controlling MRO is important for optimizing ALD-grown amorphous films for future functional devices and renewable energy applications.
Article
Materials Science, Multidisciplinary
Amir Abbas Kazemzadeh Farizhandi, Mahmood Mamivand
Summary: Prediction of microstructure evolution is crucial for controlling material properties. Simulation tools based on physical concepts are not practical for urgent needs or large datasets. We propose a PredRNN model for microstructure prediction, which improves on the speed and accuracy of the phase field method using spinodal decomposition simulation data of FeCrCo alloy.
COMPUTATIONAL MATERIALS SCIENCE
(2023)
Article
Engineering, Electrical & Electronic
Lin Lin, Ryan Jacobs, Dane Morgan, John Booske
Summary: Recent experiments on the perovskite oxide SrVO3 demonstrate the potential for achieving low work functions using surface dipoles on polar perovskites. Additional density functional theory calculations suggest that many other perovskites, including BaMoO3, may also exhibit low work function. In this study, the thermionic emission behavior of BaMoO3 was investigated, showing a temperature limited emission current density that increases and saturates with increasing voltage. The material exhibits an overall effective work function comparable to LaB6, but higher than the lowest work function predicted by DFT. The discrepancy is attributed to patch field effects caused by nanoscale features on individual surface facets. BaMoO3 also exhibits some instability at high temperatures, but shows comparable emission behavior to LaB6 at temperatures below 1200 degrees C, making it a potential vacuum electron source for applications such as electron microscopes and electron beam writers.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Engineering, Electrical & Electronic
Dongzheng Chen, Ryan Jacobs, Dane Morgan, John Booske
Summary: In the study of thermionic electron emission, the shape of the Miram curve knee, which represents the transition between the exponential region and the saturated emission regions, plays a crucial role in evaluating the quality of thermionic vacuum cathodes. This research provides a comprehensive understanding of the physical factors, including the space charge effect and the patch field effect, that determine the shape of the knee. By using a model system with a periodic, equal-width striped work function distribution, the study illustrates how these physical effects restrict the emission current density near the Miram curve knee. The results identify three key physical parameters that significantly impact the shape of the Miram curve, providing new insights for the design of thermionic cathodes in vacuum electronic devices.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Materials Science, Multidisciplinary
Jianqi Xi, Yeqi Shi, Vitaly Pronskikh, Frederique Pellemoine, Dane Morgan, Izabela Szlufarska
Summary: Using atomistic simulations, we investigated the behavior of helium bubbles in beryllium, focusing on their shape, stability, and diffusivity. We found that helium bubbles become unstable and change shape through plastic deformation when the helium-vacancy ratio exceeds 1.25. The dominant diffusion mechanism of helium bubbles changes from surface diffusion to volume diffusion at around 900 K. The results provide valuable insights into the microstructural evolution and properties of irradiated materials.
JOURNAL OF NUCLEAR MATERIALS
(2023)
Article
Multidisciplinary Sciences
Yutao Dong, Mehrdad Abbasi, Jun Meng, Lazarus German, Corey Carlos, Jun Li, Ziyi Zhang, Dane Morgan, Jinwoo Hwang, Xudong Wang
Summary: Amorphous titanium dioxide (TiO2) film coating by atomic layer deposition (ALD) is a promising strategy to extend the photoelectrode lifetime for solar fuel generation. In this work, it is revealed that residual chlorine (Cl) ligands are detrimental to the silicon (Si) photoanode lifetime. Post-ALD in-situ water treatment effectively improves the film stoichiometry and preserves the amorphous phase, leading to a substantially improved lifetime for the protected Si photoanode.
NATURE COMMUNICATIONS
(2023)
Article
Multidisciplinary Sciences
Ryan Jacobs, Priyam Patki, Matthew J. Lynch, Steven Chen, Dane Morgan, Kevin G. Field
Summary: Accurate quantification of nanoscale cavities in irradiated alloys is achieved using the Mask R-CNN model, which provides insights into alloy performance and swelling metrics. The model demonstrates good performance in terms of statistical and materials property-centric evaluations, enabling accurate assessments of swelling in alloys.
SCIENTIFIC REPORTS
(2023)
Review
Physics, Applied
Lin Lin, Ryan Jacobs, Tianyu Ma, Dongzheng Chen, John Booske, Dane Morgan
Summary: In this review, the authors define different aspects of the work function and discuss the role of electric fields in work-function measurement and interpretation. They review standard experimental approaches and computational tools for measuring and predicting work function, and explore the influence of materials chemistry and structure on work-function trends. The authors also discuss the role of work function in various applications and provide guidance for engineering work-function values.
PHYSICAL REVIEW APPLIED
(2023)
Article
Energy & Fuels
Xiu-Liang Lv, Patrick T. Sullivan, Wenjie Li, Hui-Chun Fu, Ryan Jacobs, Chih-Jung Chen, Dane Morgan, Song Jin, Dawei Feng
Summary: This study successfully synthesized an ionic liquid-mimicking catholyte for aqueous organic redox flow batteries (AORFBs) that demonstrated high performance in terms of stability, power, and energy density. The optimized catholyte showed robust cycling stability, high power density, and high energy density, paving the way for low-cost and scalable AORFBs.
Article
Chemistry, Multidisciplinary
Ziyi Zhang, Maciej P. Polak, Corey Carlos, Yutao Dong, Dane Morgan, Xudong Wang
Summary: Two-dimensional ferromagnetic materials with strong room-temperature ferromagnetism have been synthesized using an ionic layer epitaxy strategy. The ferromagnetic strength of the NiOOH nanosheets can be controlled by adjusting the surfactant monolayer density and annealing process, offering a promising pathway for achieving strong ferromagnetism in two-dimensional materials for spintronic applications.
