Article
Chemistry, Physical
Nadine Eissmann, Uwe Muehle, Uwe Gaitzsch, Gunnar Walther, Thomas Weissgaerber, Bernd Kieback
Summary: The effect of titanium addition beyond the solubility limit was investigated to demonstrate the precipitation hardening possibility of the Cantor alloy CoCrFeMnNi. Following appropriate heat treatment, a significant increase in hardness was detected due to nanometer-sized precipitates identified through TEM analysis.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Materials Science, Multidisciplinary
Junhua Hou, Jianjun Li, Wenjun Lu
Summary: A novel phenomenon of twin boundary-assisted precipitation of sigma phase in a non-equiatomic quinary high-entropy alloy upon high-temperature annealing was revealed. The diffusion of solutes and subsequent precipitation of sigma phase are mainly driven by the Gibbs free energy difference between the 9R structure and the adjacent matrix, as observed in systematic electron microscope studies. These findings provide a fundamental understanding of sigma phase formation in polycrystalline HEAs.
Article
Chemistry, Physical
Jing Guo, Chenghao Liu, Dexing Wang, Lingfeng Xu, Kaikai Song, Ming Gao
Summary: Al1.8CrCuFeNi2 high-entropy alloy coatings with different TiC contents were prepared using laser cladding. The effect of TiC on the microstructure, hardness and wear resistance of the coatings was investigated. It was found that the addition of TiC enhanced the hardness and decreased the wear loss of the high-entropy alloy coatings by acting as fine-grain strengthening and dispersion strengthening.
Article
Engineering, Mechanical
Zhihong Wu, Hongchao Kou, Jinshan Li, Samuel Hemery, Nana Chen, Junhui Tang, Fengming Qiang, Fan Sun, Frederic Prima
Summary: Dwell fatigue failure of titanium alloy components has been a major threat to aircraft safety for the past 50 years. Designing a microstructure with low primary alpha phase content can achieve high strength and low sensitivity to dwell loading. Cracking occurs primarily along preexisting slip bands and twist grain boundaries. Load holding plays a significant role in crack initiation and switching of crack modes.
INTERNATIONAL JOURNAL OF PLASTICITY
(2022)
Article
Materials Science, Multidisciplinary
Qun Yang, Yang Hu, Jian-Min Zuo
Summary: This study examined the dislocation structure of slip bands in high entropy alloy (HEA) nanopillars oriented for single slip, providing experimental evidence on the dislocation organization in a slip band and comparing the results with previously proposed models. The unique aspects of HEA that enable such observations were investigated through an examination of the dislocation microstructure and its response to applied forces in the nanopillars.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2021)
Article
Materials Science, Multidisciplinary
Tsai-Fu Chung, Shih-Yuan Lu, Yo-Shiuan Lin, You-Lin Li, Po-Han Chiu, Chien-Nan Hsiao, Chih-Yuan Chen, Chin-Lung Kuo, Jien-Wei Yeh, Shing-Hoa Wang, Woei-Shyan Lee, Jer-Ren Yang
Summary: The grain structure and deformation characteristics of a high-entropy alloy were studied. It was found that annealing produced micro and nanotwin structures, and at high strain rates, finer single-variant deformation nanotwins were formed.
MATERIALS CHARACTERIZATION
(2022)
Article
Materials Science, Ceramics
Yi Zhou, Zhen-Yong Lao, Wei-Ming Guo, Si-Chun Luo, Hua-Tay Lin
Summary: This study prepared Ti(C0.7N0.3)-based cermets with pre-synthesized high-entropy (Ta0.2W0.2Nb0.2Mo0.2V0.2)C carbide as the reinforcing phase by pressureless sintering at 1600 degrees C. The addition of 10 wt% (Ta0.2W0.2Nb0.2Mo0.2V0.2)C increased the Vickers hardness and fracture toughness of the cermets, and significantly enhanced its wear resistance. This work demonstrates the potential of using high-entropy carbide as an effective reinforcing phase in high-performance Ti(C0.7N0.3)-based cermets.
CERAMICS INTERNATIONAL
(2023)
Article
Materials Science, Multidisciplinary
Chokkakula L. P. Pavithra, Reddy Kunda Siri Kiran Janardhana, Kolan Madhav Reddy, Chandrasekhar Murapaka, Xiaodong Wang, Suhash Ranjan Dey
Summary: This study achieved the synthesis of one-dimensional high-entropy alloy nanowires through an electrochemical method, demonstrating a unique nanostructure and uniform chemical composition, which opens up new possibilities for the application of high-entropy alloys at lower dimensions.
MATERIALS RESEARCH LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Shao-yu Yen, Yu-chen Liu, Shun-hsiang Chu, Che-wei Chang, Shih-kang Lin, Ming-Hung Tsai
Summary: The Al10Co19Cr16Fe20Ni35 high entropy alloy was fabricated and characterized using transmission electron microscopy and CALPHAD method. The microstructure consisted of a face-centered cubic (fcc) phase matrix with B2 precipitates. The designed alloy showed a product of ultimate tensile strength and elongation of 38 GPa.%, which was among the highest in the Al-Co-Cr-Fe-Ni systems. The precipitation strengthening mechanism was evaluated using the Ashby-Orowan model. The high strength and high elongation in the designed alloy resulted from the B2 precipitate-strengthened fcc microstructure.
Article
Nanoscience & Nanotechnology
Jinyeon Kim, Jong Wook Lim, Joon Kon Kim, Do Hyang Kim, Eun Soo Park, Hye Jung Chang
Summary: Using a precession electron diffraction technique, we investigated the irradiation-induced recrystallization and polygonization in a CrFeCoNiCu high-entropy alloy. The results show that the irradiation dose and material entropy have significant effects on recrystallization, with discontinuous dynamic recrystallization preferentially occurring near the surface.
SCRIPTA MATERIALIA
(2021)
Article
Materials Science, Multidisciplinary
Alok Singh, Takanobu Hiroto, Hiroyuki Watanabe, Naoko Ikeo, Toshiji Mukai, Koichi Tsuchiya
Summary: Addition of Al to equiatomic high entropy alloy promotes formation of BCC phase and sigma phase. Straining by caliber rolling induces morphological changes related to planar faults, where sigma phase nucleates first on the matrix faults followed by formation of B2 phase driven by elemental concentration changes. This study provides insights into the formation mechanisms of different phases in the alloy.
MATERIALS CHARACTERIZATION
(2021)
Article
Materials Science, Multidisciplinary
Yonggang Yan, Kade A. McGarrity, Daniel J. Delia, Curtis Fekety, Kun Wang
Summary: This study revealed the oxidation resistance mechanism of WTaNbTiAl RHEA through delicate microstructural analysis of oxides, which assists in guiding the design of oxidation-resistant high entropy alloys.
Article
Engineering, Mechanical
Kaiju Lu, Ankur Chauhan, Dimitri Litvinov, Jarir Aktaa
Summary: The low-cycle fatigue behavior of a CoCrFeMnNi high-entropy alloy was compared at room temperature and 550 degrees C. It was found that at 550 degrees C, the alloy exhibited different slip modes and reduced fatigue life compared to room temperature.
INTERNATIONAL JOURNAL OF FATIGUE
(2022)
Article
Chemistry, Multidisciplinary
Jingyang Zhang, Qing Yu, Qing Wang, Jia Li, Zhibo Zhang, Tianyu Wang, Shuo Shuang, Qihong Fang, Qiaoshi Zeng, Yong Yang
Summary: This study successfully synthesized strong and ductile cermet nanosheets through the reaction between high entropy alloy nanocrystals and poly-vinyl alcohol, overcoming the brittleness issue faced by conventional cermets.
Article
Materials Science, Coatings & Films
Ji Wang, Rui Shu, Anna Elsukova, Jianlong Chai, Yabin Zhu, Cunfeng Yao, Per O. a. Persson, Arnaud le Febvrier, Per Eklund, Smita G. Rao
Summary: Refractory high-entropy protective coatings are promising for nuclear fuel cladding applications due to their corrosion and irradiation resistant properties. TiZrNbTaV metallic and (TiZrNbTaV)N films were deposited and irradiated, with different structural behavior observed. The stable structure of (TiZrNbTaV)N film under high temperature irradiation indicates its potential as a protective coating for nuclear fuel claddings.
SURFACE & COATINGS TECHNOLOGY
(2023)
Article
Chemistry, Physical
N. F. Shkodich, I. D. Kovalev, K. Kuskov, D. Yu Kovalev, Yu S. Vergunova, Yu B. Scheck, S. G. Vadchenko, O. Politano, F. Baras, A. S. Rogachev
Summary: A powder of equiatomic CoCrFeNiCu high entropy alloy was prepared by short-term high energy ball milling, showing grain size of fcc CoCrFeNiCu and exploring its thermal stability through various analyses. Phase evolution during annealing revealed the presence of transient phases and the formation of stable fcc phases with different Cu contents. The combination of HEBM and SPS consolidation was recommended for the fabrication of single-phase equiatomic CoCrFeNiCu HEA materials.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Materials Science, Ceramics
V. I. Vershinnikov, D. Yu Kovalev
Summary: In this study, the V2AlC MAX phase was synthesized by self-propagating high-temperature synthesis (SHS) in molten NaCl salt, followed by acid leaching. The resulting powder product contains V2AlC, VAl, VC, MgO, MgAl2O4 phases. By adjusting the initial material ratios, a V2AlC powder with up to 95% purity was obtained.
CERAMICS INTERNATIONAL
(2023)
Article
Materials Science, Multidisciplinary
A. A. Vinokurov, D. Yu Kovalev, G. R. Nigmatullina, N. N. Dremova, S. P. Shilkin
Summary: In this study, almost spherical niobium diboride nanoparticles were successfully synthesized using ionic melts under specific conditions. The average size of these nanoparticles is around 12 to 17 nm, and they possess a hexagonal structure.
INORGANIC MATERIALS
(2022)
Article
Chemistry, Physical
A. S. Rogachev, S. G. Vadchenko, D. Yu. Kovalev, N. A. Kochetov, M. Zhukovskyi, T. Orlova, A. S. Mukasyan
Summary: The stability of high-entropy alloys is crucial for their fundamentals and practical applications. This study experimentally investigated the phase and microstructural evolution of a near-equiatomic Co0.18Cr0.20Fe0.24Ni0.19Ti0.19 alloy during long-term isothermal annealing. The alloy exhibited a stable composition after prolonged heat treatment, with released Ti atoms acting as getters for oxygen and forming sub-micron TiOx particles.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Multidisciplinary
Yu. V. Bogatov, V. A. Shcherbakov, A. V. Karpov, A. E. Sytschev, D. Yu. Kovalev
Summary: NiTi samples with a density of 6.65 g/cm(3) were prepared by forced SHS compaction and their structure was investigated using scanning electron microscopy and X-ray diffraction analysis. In addition to NiTi (B2 + R), secondary phases including Ti2Ni, Ni4Ti3, and Ni were found in the SHS-compacted samples. The electrical resistivity as a function of temperature within the range of 290-1150 K was studied.
INTERNATIONAL JOURNAL OF SELF-PROPAGATING HIGH-TEMPERATURE SYNTHESIS
(2022)
Article
Chemistry, Physical
Dmitry Roshchupkin, Dmitry Kovalev
Summary: The ordered Ca3TaGa3Si2O14 and disordered La3Ga5SiO14 crystals were grown using the Czochralski method. Thermal expansion coefficients ac and aa were determined by analyzing X-ray diffraction spectra measured in the temperature range of 25 to 1000 degrees C. The results show that the coefficients are linear up to 800 degrees C but become nonlinear at higher temperatures due to the decrease in Ga content in the crystal lattice.
Article
Materials Science, Multidisciplinary
Q. Bizot, O. Politano, V. Turlo, F. Baras
Summary: Our work provides a nanoscale description of solidification processes for polycrystalline Ni in additive manufacturing, focusing on the thermal effects associated with non-stationary conditions. Directional solidification and homogeneous nucleation are studied as a function of operating parameters. We show that a planar solid/liquid interface propagates at a constant speed in the presence of a temperature gradient, and a columnar-to-equiaxed transition can be captured by adding cooling to the melt pool.
Article
Physics, Applied
O. Politano, F. Baras
Summary: Thermocapillary convection was investigated in a nanoscale metallic system of pure Ni using molecular dynamics. The study focused on the influence of a heat flux on the liquid metal, which led to the development of counter-rotating convection cells due to the gradient of surface tension along the interface. Parameters such as Prandtl, Marangoni, and Peclet numbers were used to interpret the results and demonstrate the effects of laser power and system size on pool shape and flow characteristics.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Florence Baras, Olivier Politano, Yuwei Li, Vladyslav Turlo, Sergey Zharkov
Summary: Using molecular dynamics simulations, nanometric multilayers composed of immiscible silver (Ag) and nickel (Ni) metals were studied. The results showed that at high temperatures, there was enhanced mobility and partial dissolution of Ni within the amorphous Ag at the interface. The study also examined the grooving phenomenon at grain boundaries in polycrystalline layers.
Article
Chemistry, Multidisciplinary
Maksim Poliakov, Dmitry Kovalev, Sergei Vadchenko, Dmitry Moskovskikh, Philipp Kiryukhantsev-Korneev, Lidiya Volkova, Alexander Dudin, Andrey Orlov, Andrey Goryachev, Alexander Rogachev
Summary: In this work, a high-entropy thin-film CoCrFeNiTix was deposited on a Si/SiO2 substrate using magnetron sputtering. The film had an amorphous atomic structure and retained this structure after annealing up to 400°C. It showed a single-phase structure, a smooth surface, and a uniform distribution of elements. This study demonstrates the potential use of high-entropy alloy films as resistive elements in contemporary and future microelectronic devices.
Article
Materials Science, Multidisciplinary
Yu. V. Bogatov, V. A. Shcherbakov, D. Yu. Kovalev
Summary: TiC-NiTi cermet composites were fabricated by forced SHS compaction, and their phase composition, microstructure, and microhardness were characterized. The stoichiometry and particle size of TiC changed with the increase of Ni + Ti content, leading to a significant decrease in microhardness.
INTERNATIONAL JOURNAL OF SELF-PROPAGATING HIGH-TEMPERATURE SYNTHESIS
(2023)
Article
Physics, Fluids & Plasmas
F. Baras, Alejandro L. Garcia, M. Malek Mansour
Summary: The traditional stochastic modeling of reactive systems is limited to systems involving a single elementary reaction. A recent alternative stochastic modeling has been proposed to overcome this limitation, but it is incompatible with the traditional approach. This paper shows that results obtained through microscopic simulations unambiguously support the predictions of traditional stochastic modeling and invalidate the recently proposed alternative.
Article
Materials Science, Ceramics
A. Yu Potanin, E. A. Bashkirov, E. A. Levashov, P. A. Loginov, M. A. Berezin, D. Yu Kovalev
Summary: This paper focuses on studying the effect of mechanical activation on the macrokinetic characteristics of combustion and structure formation of Fe-Al-B reaction mixtures. By constructing phase diagrams and investigating structural phase transformations during combustion, the optimal mode for synthesizing a high percentage of Fe2AlB2 phase is determined.
CERAMICS INTERNATIONAL
(2023)
Article
Materials Science, Ceramics
Dan Zhao, Yi Feng, Zhipeng Pi, Fan Zhang
Summary: Phase equilibria in the ZrO2-GdO1.5-TaO2.5 (ZGTO) system were experimentally investigated, and the differences between ZGTO and the existing ZrO2-YO1.5-TaO2.5 (ZYTO) were discussed. The study is useful for thermodynamic assessment of ZGTO and can guide the design of novel thermal barrier coatings materials.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2024)
Article
Materials Science, Ceramics
Yutaka Ohya, Wingki Mey Hendra, Chika Takai-Yamashita, Takayuki Ban
Summary: Diffusion couples of rutile and corundum single crystals were prepared and examined to study the solid solution and precipitation of corundum in rutile during cooling. Different precipitation forms of corundum were observed under different cooling conditions.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2024)
Article
Materials Science, Ceramics
Jiaming Zhan, Yunfa Guo, Hao Wang
Summary: This study systematically investigates the mechanical behaviors of calcium fluoride in humid environments. The effects of water on the deformation and plastic enhancement of CaF2 under indentation are explored through microindentation experiments, atomic simulations, and Raman spectroscopy measurement.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2024)
Article
Materials Science, Ceramics
Hangfeng Zhang, Henry Giddens, Theo Graves Saunders, Matteo Palma, Isaac Abrahams, Haixue Yan, Yang Hao
Summary: The relationship between low and high frequency tunabilities in tin substituted barium titanate ceramics was investigated. It was found that there are differences in tunabilities at different frequencies due to the different activities of larger ferroelectric domains and polar nanoclusters.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2024)
Article
Materials Science, Ceramics
Kaibiao Xi, Jiacheng Liu, Beibei Song, Huarong Cheng, Yihao Li, Xiaole Yu, Mupeng Zheng, Mankang Zhu, Yudong Hou
Summary: Composite modulation in the superparaelectric state of the BTBZ-CT system is proposed as an effective strategy to achieve both NTCC and excellent energy storage performance in dielectric ceramics. The addition of BZ and CT to BT ferroelectrics can move the SPE state to the normal use temperature zone, resulting in enhanced NTCC characteristics and energy storage performance. Furthermore, intentional precipitation of CT at grain boundaries can refine the grain size, increase the bandgap, and strengthen the local electric field distribution, thereby enhancing the breakdown electric field.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2024)
Article
Materials Science, Ceramics
Hamed Salimkhani, Lovro Fulanovic, Till Froemling
Summary: The demand for robust multilayer ceramic capacitors with high-temperature and high-power capabilities is increasing rapidly. However, cost-effective production is a challenge. This study investigates the use of Na0.5Bi0.5TiO3-based materials as promising lead-free options. By adding sintering aids, the sintering temperature of Na0.5Bi0.5TiO3-BaTiO3-CaZrO3-BiAlO3 solid solutions was successfully reduced to 975 degrees C, suitable for co-sintering with Cu electrodes without adverse effects on capacitor properties.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2024)
Article
Materials Science, Ceramics
Mingxing Li, Ran Mo, Zeshui Xu, Jie Zhou, Conglin Zhang, Xuefeng Cui, Fang Ye, Laifei Cheng, Ralf Riedel
Summary: Polymer infiltration and pyrolysis is an effective method for preparing ceramic matrix composites. The transformation of polymer to ceramic during the process affects the residual stress and interface behavior in the composites.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2024)
Article
Materials Science, Ceramics
Yan Kang, Lin Chen, Chang-Jiu Li, Guan-Jun Yang
Summary: A novel abradable seal coating with low hardness and high bonding strength was successfully designed and prepared. This coating has significantly higher abradability and erosion resistance compared to metal-based coatings, and can retain excellent abradability and have a long lifetime during service.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2024)
Article
Materials Science, Ceramics
Qingzhong Song, Xiangdong Zha, Ming Gao, Yingche Ma
Summary: This study analyzes the influence of calcia refractory purity on the properties of calcia crucibles. Higher purity calcia results in well-developed grains and improved hydration resistance, leading to better high-temperature strength and thermal shock resistance. In contrast, lower purity calcia crucibles exhibit inferior properties. Therefore, high-purity calcia is considered a potential refractory for manufacturing oxide crucibles.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2024)
Article
Materials Science, Ceramics
Sehreish Abrar, Faisal Nazeer, Zhuang Ma, Ling Liu, Abdul Malik, Mustafa Kamal, Abdullah G. Al-Sehemi
Summary: To raise the operating temperature of Si-based ceramic matrix composites (CMCs), researchers have applied thermal/environmental barrier coating (T/EBCs) materials, typically rare earth silicates. However, the high thermal conductivity and the mismatch of thermal expansion have been major challenges in developing new materials that can offer thermal insulation and environmental protection to CMCs. In this study, entropy engineering was used to create a multicomponent equi-atomic single-phase pyro silicate with extremely low thermal conductivity and enhanced water vapor corrosion resistance. The research findings show the potential of high entropy disilicates in achieving ultra-low thermal conductivity and low weight loss in corrosive environments.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2024)
Article
Materials Science, Ceramics
Zi-bo Niu, Daxin Li, Dechang Jia, Zhihua Yang, Kunpeng Lin, Paolo Colombo, Ralf Riedel, Yu Zhou
Summary: In this study, SiBCN ceramics with a special structure were prepared to improve the oxidation resistance. The effect of the structure on oxidation behavior and kinetics was investigated, revealing that the special structure can effectively inhibit heterogeneous oxidation and enhance the oxide layer composition.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2024)
Article
Materials Science, Ceramics
Melike Donmez, Metehan Erdogan, Cihangir Duran
Summary: The limited densification of CeO2 ceramics was improved by using an anorthite-based glass, resulting in high dielectric constant and quality factor with minimum dielectric loss. The CeO2-(anorthite-based) glass ceramic showed promising results in terms of low temperature densification and microwave properties.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2024)
Article
Materials Science, Ceramics
S. Rahmati, R. G. A. Veiga, J. Mostaghimi, T. Coyle, A. Dolatabadi
Summary: This study provides an atomic-scale description of the high-velocity impact of alpha-Al2O3 particles onto an alpha-Al2O3 substrate during Aerosol Deposition (AD). The results suggest that the crystal orientation plays a crucial role in both plasticity and damage of the nanoparticles. Impact velocity has a direct correlation with plasticity and fragmentation, but adhesion efficiency has only a marginal increase. The crucial element lies in the substrate's surface alterations caused by the fragments left on the substrate after impact.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2024)
Article
Materials Science, Ceramics
Bo-Wen Chen, Yan-Mei Kan, De-Wei Ni, Chun-Jing Liao, Hong-Da Wang, Yu-Sheng Ding, Shao-Ming Dong
Summary: This study characterized the long-term and repeated ablation properties of modified Cf/HfC-SiC composites with YB4-Al2O3-Si3N4 under an air plasma torch. The structural stability and viscosity of the oxide layer were found to affect the ablation resistance of the composites. By forming nano c-HfO2 grains and high-viscosity Al-Si-Y-O glassy phase, the structural stability of the oxide layer was improved, resulting in enhanced ablation resistance. However, the oxidation of Si3N4 led to the formation of NO, NO2, and excessive SiO2 glassy phase, which resulted in a porous structure and reduced the viscosity of the oxide layer. Therefore, the addition of Si3N4 decreased the ablation resistance of the composites.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2024)
Article
Materials Science, Ceramics
Yongxing Wei, Huawei Zhang, Siyuan Dong, Changqing Jin, Chenxing Bai, Junle Dai, Zengzhe Xi, Zhonghua Dai, Zengyun Jian, Li Jin
Summary: In this study, solid solutions of xBi(Ni1/2Hf1/2)O-3-(1 - x)PbTiO3 (xBNH-PT) were synthesized to investigate their phase boundary behaviors and physical properties. The presence of a tetragonal-pseudocubic phase boundary and a spontaneous ferroelectric-relaxor transition at specific compositions were confirmed. The introduction of a tetragonal-pseudocubic phase boundary improved the piezoelectric properties and suppressed the spontaneous ferroelectric-relaxor transition.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2024)
