Article
Materials Science, Multidisciplinary
Enkuan Zhang, Ying Tang, Mingwen Wen, Abdulmonem Obaied, Irina Roslyakova, Lijun Zhang
Summary: Refractory high entropy alloys (RHEAs) have great potential for ultrahigh-temperature applications. In this paper, the authors evaluated the Gibbs energy expressions for pure Mo, Nb, Ta and W, and developed a thermodynamic database for the Mo-Nb-Ta-W quaternary system. The calculated results showed good agreement with experimental and theoretical data. Additionally, experimental investigation and high-throughput mapping were performed to further verify the reliability of the database.
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
Marta Pozuelo, Jaime Marian
Summary: In this study, the direct link between the strength of micron-sized specimens of high-entropy alloys and deviations from equiatomic stoichiometry was established. The compositional fluctuations near the micropillar tip were found to be the best quantitative predictor of yield strength.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Nanoscience & Nanotechnology
Xinran Zhou, Sicong He, Jaime Marian
Summary: The Nb-Mo-Ta-W system, a model alloy of the refractory multi-principal element alloy family, exhibits exceptional mechanical properties at high temperature due to its highly twisted screw dislocations with a high concentration of kinks and cross-kinks. This study quantifies the contribution of the 'self-pinning' effect to the total strength using a kinetic Monte Carlo model, and reveals that the self-pinning stress remains even at high temperatures.
SCRIPTA MATERIALIA
(2023)
Article
Materials Science, Ceramics
David Medved', Michal Ivor, Alexandra Kovalcikova, Erika Mudra, Tamas Csanadi, Richard Sedlak, Hakan Unsal, Peter Tatarko, Monika Tatarkova, Pavol Sajgalik, Jan Dusza
Summary: The wear characteristics of a high-entropy carbide were studied using a ball-on-flat technique. The wear behavior showed that the friction coefficient and specific wear rate increased with increasing load, and the dominant wear mechanism was identified as mechanical wear.
INTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY
(2022)
Article
Nanoscience & Nanotechnology
Minhyung Ahn, Yongmo Park, Seung Hwan Lee, Sieun Chae, Jihang Lee, John T. Heron, Emmanouil Kioupakis, Wei D. Lu, Jamie D. Phillips
Summary: High-entropy-oxide-based memristors composed of Zr, Hf, Nb, Ta, Mo, and W oxides demonstrate uniform distribution of vacancies and low stochastic behavior in resistive switching, showing promise for neuromorphic applications. These memristors exhibit forming-free operation, low device and cycle variability, gradual conductance modulation, 6-bit operation, and long retention.
ADVANCED ELECTRONIC MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Wei-Bing Liao, Chen-Hao Xu, Tian-Li Wang, Chuang-Shi Feng, Muhammad Abubaker Khan, Ghulam Yasin
Summary: Nano-structured refractory high-entropy alloy films were prepared and their oxidation behavior and effects on microstructure and mechanical properties were investigated. The films exhibited stable structure and mechanical properties under oxidation conditions up to 400 degrees Celsius.
Article
Materials Science, Multidisciplinary
Sicong He, Xinran Zhou, Dan Mordehai, Jaime Marian
Summary: The refractory multi-element alloys (RMEA) with body-centered cubic (bcc) structure have attracted much attention as potential high-temperature materials. Recent research on Nb-Mo-Ta-W alloys suggests that the role of edge dislocations, caused by atomic-level chemical fluctuations, plays a key role in their remarkable strength above 1000℃. This study proposes a strengthening mechanism based on thermal super-jogs in edge dislocations, which act as strong obstacles to dislocation motion, and explains the strength plateau observed in these alloys.
Article
Chemistry, Physical
Yiyong Zhang, Zhibin Zhang, Zhiyuan Jing, Haoxu Wang, Wen Yao, Xiubing Liang
Summary: (Mo-Ta-W)-C and (Nb-Ta-W)-C carbide thin films were prepared by non-reactive magnetron co-sputtering and their compositions, structures, and properties were investigated. The results showed that the (Mo-Ta-W)-C thin films had a double-layer structure with a small surface roughness, while the (Nb-Ta-W)-C thin films had an amorphous structure and a granular surface. Both films contained free carbon phases and exhibited high hardness. Moreover, the (Nb-Ta-W)-C thin films showed excellent corrosion resistance and optical properties.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Coatings & Films
Tomasz Stasiak, Pavel Soucek, Vilma Bursikova, Nikola Koutna, Zsolt Czigany, Katalin Balazsi, Petr Vasina
Summary: High entropy alloy and nitride coatings from the Cr-Hf-Mo-Ta-W system were deposited by reactive magnetron sputtering. The effects of deposition parameters on the microstructure and mechanical properties of the coatings were investigated. The results showed that the deposition conditions influenced the microstructure of the coatings, with high nitrogen flow leading to the formation of a major fcc nitride phase with higher hardness and Young's modulus. The study provides insights into the influence of nitrogen flow on the microstructural features of the coatings.
SURFACE & COATINGS TECHNOLOGY
(2022)
Article
Materials Science, Ceramics
Yu-Zhang Zhou, Kun-Heng Huang, Guang-Xu Bo, Si-Chun Luo, Wei-Ming Guo, Shi-Kuan Sun, Hua-Tay Lin
Summary: High hardness and high toughness (Ti,Nb,Ta,Mo,W)(C,N)-based ceramics were prepared using pre-synthesized high-entropy carbonitride (HECN) powder and high-entropy alloy (HEA) via spark plasma sintering, and the fracture toughness of the ceramics was significantly improved.
CERAMICS INTERNATIONAL
(2023)
Article
Materials Science, Coatings & Films
Bih-Show Lou, Chaur-Jeng Wang, Yen-Yu Chen, Sheng-Bo Hung, Yu-Chen Lin, Jyh-Wei Lee
Summary: This study fabricated refractory MEA thin films of W-Nb-Ta-Ti and W-Nb-Ta-Ti-N, and demonstrated how the structure and microstructure of the films can be controlled by adjusting the nitrogen concentration. The films exhibited varying hardness, adhesion properties, friction coefficients, and corrosion resistance.
SURFACE & COATINGS TECHNOLOGY
(2022)
Article
Crystallography
Zhenhua Wang, Dongming Jin, Jincan Han, Qing Wang, Zhongwei Zhang, Chuang Dong
Summary: In this study, the microstructural evolution and mechanical properties of new BCC-based high-entropy alloys with coherent B2 precipitation were investigated. Phase separation of BCC matrix and ultra-fine B2 nanoparticles were found in the alloys, which could coarsen and change in morphology after aging. The presence of Zr5Al3 phase coexisting with the B2 phase was also observed, with the Ti element enriched in the B2 phase contributing to the improved compressive mechanical properties.
Article
Materials Science, Multidisciplinary
Jijie Yang, Chaojie Liang, Chenglei Wang, Jian Huang, Bing Qiu, Mulin Liang, Weijie Liu, Yingguang Xie, Kexiang Zhang, Shengfeng Zhou
Summary: In this study, the phase structure, microstructure, and mechanical properties of high entropy alloys (HEAs) were investigated. It was found that the addition of refractory elements did not change the phase structure of the alloys but improved their strength. Among them, the alloy with Ta element exhibited the best comprehensive mechanical properties and showed excellent strength-ductility combination.
MATERIALS & DESIGN
(2022)
Article
Materials Science, Multidisciplinary
S. Schellert, B. Gorr, S. Laube, A. Kauffmann, M. Heilmaier, H. J. Christ
Summary: The oxidation resistance of alloys Ta-x-(Mo-Cr-Ti-Al)(1-x) in air at 1200 degrees C is improved with increasing Ta concentration. However, alloys with Ta concentrations less than or equal to 10 at% exhibit poor oxidation behavior. Protective CrTaO4 scales are found in alloys containing 15 and 20 at% Ta.
Article
Energy & Fuels
Jack A. Wilson, Lee J. Evitts, Alberto Fraile, Roy E. Wilson, Michael J. D. Rushton, David T. Goddard, William E. Lee, Simon C. Middleburgh
Summary: In this study, the thermal expansion behavior of equiatomic alloys in the Mo-Nb-Ta-Ti-W system was investigated using atomic-scale modeling techniques. The results showed that these techniques can reliably predict the thermal expansion behavior of high entropy alloys and concentrated solid solutions.
JOURNAL OF PHYSICS-ENERGY
(2022)
Article
Physics, Applied
Anis Biswas, N. A. Zarkevich, Y. Mudryk, Arjun K. Pathak, A. Smirnov, V. P. Balema, Duane D. Johnson, V. K. Pecharsky
Summary: Proper coupling between structural and magnetic transitions is crucial for controlling and improving the magnetocaloric properties of alloys. Chemical substitutions have been demonstrated to effectively control the magnetocaloric properties of Mn0.5Fe0.5NiSi0.94Al0.06 alloy, with B doping leading to one of the highest magnetic-field-induced entropy changes near room temperature.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Materials Science, Multidisciplinary
Ranran Su, Hongliang Zhang, Gaoyuan Ouyang, Longfei Liu, Will Nachlas, Jun Cui, Duane D. Johnson, John H. Perepezko
Summary: This study explores a two-step coating process for an innovative refractory multi-principal element alloy, demonstrating enhanced oxidation resistance at high temperatures and stable operation at 10-20% higher temperatures without forced cooling. The coating, consisting of an aluminoborosilica glass layer and RMPEA-Si-B multilayered structure, effectively protects the substrate and maintains coating integrity through borides acting as a barrier layer.
Article
Crystallography
Nikolai A. Zarkevich, Duane D. Johnson
Summary: This study identifies specific features in the potential-energy surface that lead to polymorphic behavior and establishes reliable estimates for the relative energies and temperatures associated with anharmonic vibrations and solid-solid symmetry-breaking phase transitions. Computational phonon methods are shown to be applicable in investigating anharmonic vibrations in polymorphic solids at fixed temperatures. The theoretical predictions are well supported by a range of examples and known experimental data.
Article
Materials Science, Multidisciplinary
Guillermo Vazquez, Prashant Singh, Daniel Sauceda, Richard Couperthwaite, Nicholas Britt, Khaled Youssef, Duane D. Johnson, Raymundo Arroyave
Summary: In this study, descriptor-based analytical models and meanfield methods were combined to accelerate the assessment of technologically useful properties of high-entropy alloys. The models accurately predicted target properties and revealed promising alloy concentration regions.
Article
Materials Science, Multidisciplinary
Danial Khatamsaz, Brent Vela, Prashant Singh, Duane D. Johnson, Douglas Allaire, Raymundo Arroyave
Summary: This paper presents a novel multi-information BO framework for learning materials design as a multiple objectives and constraints problem. By optimizing ductility indicators and studying manufacturing constraints, the framework efficiently explores a multi-principal-element alloy space.
Article
Materials Science, Multidisciplinary
Ranran Su, Hongliang Zhang, Gaoyuan Ouyang, Longfei Liu, Duane D. Johnson, John H. Perepezko
Summary: Refractory multiple-principal-element alloys (RMPEAs) have potential as structural materials in high-temperature oxidation environments, but their oxidation behavior and microstructures, especially at the beginning of oxidation, have not been well studied. In this research, the oxidation mechanism of an equimolar W-Mo-Ta-Nb-V alloy was investigated and compared with an equimolar W-Mo-Ta-Nb alloy without V at 1300 degrees C. The oxide scale on the RMPEA alloy was found to consist of a degradation layer, an initial oxide transition layer, a main phase aggregate oxide layer, and an outermost oxide layer. The presence of vanadium accelerated the initial degradation process by forming VO.
Article
Materials Science, Multidisciplinary
Brent Vela, Cafer Acemi, Prashant Singh, Tanner Kirk, William Trehern, Eli Norris, Duane D. Johnson, Ibrahim Karaman, Raymundo Arroyave
Summary: Development of next-generation gas turbines requires the design and fabrication of novel high-temperature structural materials capable of operating beyond 1300 degrees C. We propose a high-throughput alloy design framework that can discover new refractory multi-principal element alloys (MPEAs) for high-temperature applications under multiple property constraints. Using this framework, we identified a set of 214 MoNbV-rich alloys that meet the relevant constraints. DFT analysis and experimental characterization revealed that the Mo30Nb35Ta5V25W5 alloy outperforms 1546 MPEAs in terms of the specified constraints.
Article
Nanoscience & Nanotechnology
S. Picak, P. Singh, D. Salas, M. A. Tunes, X. Fang, L. Zhou, M. J. Kramer, Y. I. Chumlyakov, Duane D. Johnson, R. Arroyave, Y. Ren, I. Karaman
Summary: Multi-principal-element alloys offer a larger and richer design space for discovering new functionalities and their governing physics. The role of atomic short-range order (SRO) in the plasticity of these alloys has been investigated, and it was found that SRO affects the deformation and can alter the mechanical response.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Physics, Multidisciplinary
Duane D. Johnson, Prashant Singh, A. Smirnov, Nicolas Argibay
Summary: Interstitial electron density rho o is a universal metric for strength in metals, and sets the exchange-correlation parameter rs in density-functional theory. It also predicts maximum shear strength tau max and linear relationships between elastic moduli and rho o, as well as between tau max and melting/glass-transition temperature. This prediction allows for rapid and reliable selection of high-strength alloys with ductility, as demonstrated for various types of metals and validated experimentally.
PHYSICAL REVIEW LETTERS
(2023)
Article
Chemistry, Physical
Danial Khatamsaz, Brent Vela, Prashant Singh, Duane D. D. Johnson, Douglas Allaire, Raymundo Arroyave
Summary: In this study, a method for solving complex multi-objective alloy design problems was proposed. The Mo-Nb-Ti-V-W system was investigated as a representative Multi-Principal Element Alloy (MPEA) for potential use in next-generation gas turbine blades. The proposed approach successfully identified 21 Pareto-optimal alloys that satisfy all constraints, and it was found to be significantly more efficient and faster than a brute force approach.
NPJ COMPUTATIONAL MATERIALS
(2023)
Article
Chemistry, Physical
Sarojini Jeeva Panchu, Kumar Raju, Prashant Singh, Duane D. Johnson, Hendrik C. Swart
Summary: This study explores intercalation pseudocapacitance in a thicker electrode of Ni-doped MoS2 microspheres, which maintains a high gravimetric capacitance even at a high mass loading. The integration of Ni atoms stabilizes the structure of the microspheres and improves the intercalation and deintercalation of electrolyte ions. The increase in capacitance is attributed to the enhanced rate of ion insertion and extraction, which is confirmed by diffusive mechanisms.
ACS APPLIED ENERGY MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Mily Kundu, Santanu Pakhira, Renu Choudhary, Shuvankar Gupta, Sudip Chakraborty, N. Lakshminarasimhan, R. Ranganathan, Duane D. Johnson, Chandan Mazumdar
Summary: The intermetallic compound Nd2Co0.85Si2.88 with a triangular lattice exhibits single-phase synthesis only with a defective crystal structure. The system undergoes two magnetic transitions, with a high-temperature transition at around 140 K associated with a ferromagnetic interaction between itinerant Co moments, and a low-temperature transition at around 6.5 K due to the coupling between Nd-4f and Co-3d moments, which is antiferromagnetic in nature. Detailed investigations and density functional theory calculations suggest that the ground state of the compound is a magnetically frustrated spin glass with competing magnetic interactions of equal energies.
Article
Materials Science, Multidisciplinary
Zhenhua Ning, A. Smirnov, William A. Shelton, Duane D. Johnson
Summary: An efficient and accurate generalization of the removed-sphere method is presented, which can solve the Poisson equation for total charge density in a solid, accuracy and rapid convergence properties are confirmed.
Article
Materials Science, Multidisciplinary
Sudip Chakraborty, Shuvankar Gupta, Santanu Pakhira, Renu Choudhary, Anis Biswas, Yaroslav Mudryk, Vitalij K. Pecharsky, Duane D. Johnson, Chandan Mazumdar
Summary: The compound exhibits long-range antiferromagnetic order at 16 K, a long-range ferrimagnetic transition at 6.5 K, and a reentrant cluster-glass transition below Tf similar to 3 K, which could be correlated with competing antiferromagnetic and ferrimagnetic structures predicted theoretically.
Article
Materials Science, Multidisciplinary
Ankit Roy, M. F. N. Taufique, Hrishabh Khakurel, Ram Devanathan, Duane D. Johnson, Ganesh Balasubramanian
Summary: The study uses machine-learning to down select corrosion-resistant alloys and optimize descriptors to predict the corrosion resistance of MPEAs. Findings demonstrate the potential and challenges of ML when applied to complex chemical phenomena like alloy corrosion.
NPJ MATERIALS DEGRADATION
(2022)
