Article
Nanoscience & Nanotechnology
C. Ren, K. Sun, Y. F. Jia, N. Z. Zhang, Y. D. Jia, G. Wang
Summary: The study examined the microstructural evolution and mechanical properties of (FeNi)67Cr15Mn10-xAl4Ti4Mox high entropy alloys. It was found that the substitution of Mn by Mo introduced hard a precipitates into the matrix and significantly refined the grains, leading to the increase in yield strength. However, the formation of the hard a precipitates hindered the work hardening process and decreased the plasticity, resulting in a decrease in elongation at break. The highest ultimate tensile stress was obtained at x = 4, where the fracture morphology changed from a coarse grain morphology to a typical brittle fracture. Therefore, (FeNi)67Cr15Mn6Al4Ti4Mo4 showed the optimal mechanical properties overall.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Chemistry, Physical
Tianxiang Wang, Yanxin Wu, Yonggang Yang, Shiwei Tian, Yefei Zhang, Haitao Jiang
Summary: In this study, AlxCrFeMnNi2-x (x = 0.3, 0.7, 1.0) high-entropy alloys (HEAs) were designed and their microstructure and mechanical properties were investigated. Increasing the Al/Ni ratio led to a phase transition from FCC to BCC phase. The presence of B2 phase increased with higher Al/Ni ratio, but the morphology changed from spherical to cubical and weave-like due to the lattice misfit constant epsilon. The alloy with x = 0.7 showed the optimal mechanical properties with high yield strength and total ductility.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Chemistry, Physical
Ao Fu, Yuankui Cao, Zhonghao Xie, Jian Wang, Bin Liu
Summary: A novel non-equiatomic high entropy alloy (HEA) Al15.85Fe11.15Co32.11Cr10.76Ni30.13 was fabricated using a powder metallurgy method. The HEA exhibits a dual-phase microstructure consisting of face-centered-cubic (FCC) and body-center cubic (BCC) phases. It possesses high compressive yield strength, fracture strength, fracture strain, and strength at high temperature due to the uniform dispersion of L12 and B2 nanoprecipitates in the FCC and BCC phases, respectively. This finding provides guidance for the development of high-performance structural materials with a balance of strength and ductility for industrial applications.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Multidisciplinary
Ali Shafiei
Summary: A new method was proposed to predict the compositions of EHEAs in the Al-Co-Cr-Fe-Ni system, by designing new eutectic or near-eutectic alloys through mixing alloys located on the same eutectic line. Compositional maps were created to show the relations between constituent elements in eutectic alloys, suggesting that EHEAs are derived from binary and ternary eutectic alloys. The proposed diagrams can be considered as convenient methods for evaluating the composition of EHEAs in the Al-Co-Cr-Fe-Ni system.
METALS AND MATERIALS INTERNATIONAL
(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
Materials Science, Multidisciplinary
Yu-Jin Hwang, Kyu-Sik Kim, Young Sang Na, Ka Ram Lim, Kee-Ahn Lee
Summary: This study investigated the microstructure, high-temperature oxidation properties, and mechanism of a non-equiatomic Fe-Cr-Ni-Al medium entropy alloy (MEA). The microstructural observation revealed coarse grains and evenly distributed cuboidal precipitates within the grains. The alloy exhibited excellent high-temperature oxidation resistance due to the formation of a dense, stable Al2O3 layer, regardless of temperature conditions, and no breakaway oxidation occurred.
Article
Chemistry, Physical
Zhenqiang Xing, Jingyu Pang, Hongwei Zhang, Yu Ji, Zhengwang Zhu, Aimin Wang, Long Zhang, Hong Li, Huameng Fu, Haifeng Zhang
Summary: The effect of Ti content on the microstructure and mechanical properties regulation for Fe45Ni30-xCr15Al10Tix high entropy alloys (HEAs) with a duplex FCC/BCC structure is investigated. The introduction of Ti transforms the inter-dendric structure and changes the morphology of precipitates. This leads to an increase in the ultimate tensile strength of the HEAs and a maintained uniform elongation, showing excellent strength-plasticity synergy.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Nanoscience & Nanotechnology
Sebastian Lech, Wojciech Polkowski, Adelajda Polkowska, Grzegorz Cempura, Adam Kruk
Summary: The study of Ni-Fe-Cr-Al alloy revealed the presence of three different phases in the discontinuous precipitation zone, as well as discussed the development of multiple discontinuous reactions.
SCRIPTA MATERIALIA
(2021)
Article
Materials Science, Multidisciplinary
J. X. Hou, J. Y. Zhang, J. X. Zhang, J. H. Luan, Y. X. Wang, B. X. Cao, Y. L. Zhao, Z. B. Jiao, X. J. Liu, W. W. Song, P. K. Liaw, T. Yang
Summary: The precipitation morphologies, coarsening kinetics, elemental partitioning behaviors, grain structures, and tensile properties of L12-strengthened Ni39.9Co20Fe15Cr15Al6Ti4-xNbxB0.1 (x = 0 at.%, 2 at.%, and 4 at.%) high-entropy alloys were investigated. Substituting Ti with Nb resulted in a transition from spheroidal to cuboidal precipitates, increased coarsening kinetics, and phase decomposition at 800°C. Excessive Nb addition led to grain boundary precipitation and phase decomposition from L12 to lamellar-structured D019 phase. Partial substitution of Ti with Nb resulted in a chemically complex and thermally stable L12 phase, ensuring stable phase structure and clean grain boundaries, leading to excellent high-temperature mechanical properties at 700°C.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2023)
Article
Nanoscience & Nanotechnology
Yuhao Jia, Zhijun Wang, Qingfeng Wu, Feng He, Junjie Li, Jincheng Wang
Summary: It is still a challenge to increase the yield strength of eutectic high-entropy alloys. By modifying the Ni: Co ratio to introduce the gamma ' phase, a series of casting hypoeutectic high-entropy alloys with improved yield strength and ductility were developed. The results provide a feasible route for developing high-performance Ni-Co-Cr-Fe-Al casting HEAs with multiscale microstructure.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Chemistry, Physical
Jiongpei Yuan, Yujing Yang, Shougang Duan, Yong Dong, Chuanqiang Li, Zhengrong Zhang
Summary: In this study, a mathematical rule is established to accelerate the prediction of low-cost Co-free AlCraFebNic FCC/B2-structured eutectic medium entropy alloys (EMEAs). By applying this rule, the AlCr1.18FeNi2.8 and AlCrFe1.46Ni2.5 eutectic alloys are successfully predicted and their eutectic morphology is verified through experiments. These alloys exhibit excellent compressive mechanical properties and good corrosion resistance, which can be attributed to their unique lamellar microstructure and higher content of the FCC phase in AlCr1.18FeNi2.8 EHEA.
Article
Materials Science, Multidisciplinary
A. Ayrenk, I Kalay
Summary: The structure and mechanical properties of three high entropy alloys were investigated. The addition of Nb increased the hardness and yield strength, while the addition of Ti significantly improved the ductility of the alloys. Among the three alloys, Al8Co30Cr18Fe9Ni31Ti4 exhibited excellent mechanical properties due to the coherent phase relation between the precipitates and matrix.
PHILOSOPHICAL MAGAZINE
(2022)
Article
Materials Science, Multidisciplinary
Sefa Emre Sunbul, Kursat Icin, Fatma Zehra Seren, Omer Sahin, Damla Dilara Cakil, Rasit Sezer, Sultan Ozturk
Summary: In this study, a high entropy alloy (HEA) was obtained through vacuum arc melting and the microstructure, tribological properties, oxidation, and corrosion resistance of the alloy were thoroughly investigated. The alloy exhibited varying friction coefficients and wear rates under different loads, while the oxidation amount and corrosion performance were also influenced by temperature.
Article
Chemistry, Physical
P. Priputen, P. Noga, M. Novakovic, J. Potocnik, A. Antusek, R. Bujdak, E. Bachleda, M. Drienovsky, M. Nosko
Summary: The effect of Cu concentration on the order/disorder behavior of AlCoCuxFeNi multi-principal element alloys was investigated. BCC and/or FCC phases were observed in the microstructures of the alloys after casting and annealing at 1050 degrees C followed by slow cooling. Interestingly, the alloys exhibited ordered structures after casting and disordered structures after annealing and slow cooling, contrary to expectations. The ordering in the as-cast state can be explained by the strong affinity of Al to transition metals, resulting in the formation of supercell structures with specific elements occupying sublattices. Disordering after annealing has two reasons: the phase is either composed of nearly pure Cu and defaults to disorder, or it consists of randomly distributed nano-segregated regions within a single phase, appearing macroscopically disordered due to the uniform distribution of all elements in the sublattices. The formation of these nano-segregated regions may be due to the reduction of Gibbs free energy through the interplay of enthalpy and entropy during annealing.
Article
Materials Science, Multidisciplinary
Yunfei Li, Huameng Fu, Zhengwang Zhu, Long Zhang, Zhengkun Li, Hong Li, Haifeng Zhang
Summary: In this study, the effects of the Fe/Ni ratio on the microstructure, mechanical properties, and corrosion resistance of FexNi65-xCr20Al10Nb5 alloy in a 3.5 wt% NaCl solution were systematically investigated. It was observed that the dominant phases shifted from FCC to BCC with an increase in the Fe/Ni molar ratio. The strength of the alloy increased with a higher Fe/Ni ratio, while the plasticity decreased. The alloy exhibited the best corrosion resistance when x = 35, which was attributed to the dominant presence of FCC phases in the dendritic region.
ADVANCED ENGINEERING MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Fangfei Liu, Peter K. Liaw, Yong Zhang
Summary: This paper systematically reviews the mechanical behaviors and properties of BCC-structured HEAs, analyzes the effect of alloying on their mechanical properties, discusses the effects of HEA preparation and compositional regulation on corrosion resistance, and explores the application of high-throughput techniques in the field of HEAs.
Article
Materials Science, Multidisciplinary
Weiran Zhang, Yasong Li, Peter K. Liaw, Yong Zhang
Summary: This study utilizes empirical parameters to design depleted uranium high-entropy alloys (DUHEAs). The empirical criteria have been proven to be an effective means in development. UNb0.5Zr0.5Mo0.5 and UNb0.5Zr0.5Ti0.2Mo0.2 HEAs with outstanding mechanical properties have been successfully created.
Article
Materials Science, Multidisciplinary
Rongbin Li, Tian Huang, Jing Zhang, Chunxia Jiang, Yong Zhang, Peter K. Liaw
Summary: An experimental method for preparing high-entropy thin films with gradient changes of alloying elements by magnetron sputtering co-deposition was proposed in this study to evaluate the effect of alloying element composition changes on the properties of non-equal molar ratio high-entropy alloys. The (TiVCr)x-(TaW)1-x binary system thin films were deposited and their surface morphology, element composition, roughness, and phase structure were studied. The results showed that the films with x = 0.51 exhibited the best mechanical properties, hardness, and wear resistance, as well as improved radiation resistance.
Article
Materials Science, Multidisciplinary
Yasong Li, Peter K. Liaw, Yong Zhang
Summary: This study investigates the influence of Cr, Mo, and Si elements on the phase structures and properties of low-density Al-Zr-Ti-Nb high-entropy alloys, providing theoretical and scientific support for the development of advanced low-density alloys.
Article
Multidisciplinary Sciences
Kaisheng Ming, Zhengwang Zhu, Wenqing Zhu, Ben Fang, Bingqiang Wei, Peter K. Liaw, Xiaoding Wei, Jian Wang, Shijian Zheng
Summary: Crystalline-amorphous composites have the potential to achieve high strength and high ductility. Researchers fabricate a TiZr-based alloy with micrometer-size equiaxed grains that are made up of three-dimensional bicontinuous crystalline-amorphous nanoarchitectures. In situ tension and compression tests reveal enhanced ductility and strain hardening capability, providing ultra-high yield strength, ultimate tensile strength, and large uniform ductility to the alloy. Experiments combined with simulations reveal the synergetic deformation mechanisms, resulting in an effective combination of strength, ductility, and strain hardening.
Article
Materials Science, Multidisciplinary
Q. Li, J. W. Mo, S. H. Ma, F. H. Duan, Y. L. Zhao, S. F. Liu, W. H. Liu, S. J. Zhao, C. T. Liu, P. K. Liaw, T. Yang
Summary: In this study, it was found that the long-standing problem of hydrogen embrittlement (HE) in metallic materials can be effectively eliminated in Fex(CrCoNi)1-x face-centered cubic (fcc) high-entropy alloys (HEAs) by triggering localized segregation of Cr at grain boundaries (GBs). Increasing the Fe concentration significantly improves the HE resistance, reduces ductility loss, and transforms the fracture mode. The increased Fe concentration promotes nanoscale Cr segregation at GBs, enhancing the GBs' cohesive strength and suppressing local hydrogen segregation, thus achieving outstanding HE resistance.
Article
Engineering, Mechanical
Yang Chen, Shuo Wang, Hui Feng, Weipeng Li, Bin Liu, Jia Li, Yong Liu, Peter K. Liaw, Qihong Fang
Summary: By conducting high-resolution transmission electron microscopy and random field theory informed discrete dislocation dynamics simulations, this study reveals the influence mechanism of heterogeneous lattice strain on the complex interaction between dislocations and dislocation loops in high entropy alloys (HEAs) under irradiation. The results show that lattice-strain-induced irradiation hardening decreases, in line with the excellent irradiation hardening resistance of HEAs observed in recent experiments. A new cross-slip mechanism is also discovered, involving the co-linear reaction between dislocations and rhombus perfect loops. This study provides insights into the mesoscopic-level irradiation damage behavior, guiding the development of advanced HEA materials for nuclear energy applications through the regulation of heterogeneous lattice strain.
INTERNATIONAL JOURNAL OF PLASTICITY
(2023)
Article
Engineering, Mechanical
Mingyu Fan, Zhongwu Zhang, Ye Cui, Liyuan Liu, Yingwei Liu, PeterK. Liaw
Summary: A novel nanoscale superlattice precipitate (NSP) with superior strengthening effect is developed by rare-earth Er alloying to magnesium alloys. The newly-developed cast Mg-Y-Zn-Er alloy shows high yield strength, tensile strength, and good ductility. The structure and optimization mechanism of the NSP are systematically investigated using transmission electron microscopy and first-principles calculations.
INTERNATIONAL JOURNAL OF PLASTICITY
(2023)
Correction
Multidisciplinary Sciences
Zongrui Pei, Junqi Yin, Peter. K. K. Liaw, Dierk Raabe
NATURE COMMUNICATIONS
(2023)
Article
Chemistry, Physical
Christopher Tandoc, Yong-Jie Hu, Liang Qi, Peter K. Liaw
Summary: Severe lattice distortion is a key feature of high-entropy alloys, but accurate characterizations of lattice distortion are scarce due to high costs. We present a physics-based statistical model for efficient prediction of lattice distortion in refractory non-dilute/high-entropy alloys. The model improves accuracy by considering interatomic bonding properties instead of atomic size mismatch.
NPJ COMPUTATIONAL MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
B. Steingrimsson, X. Fan, R. Feng, P. K. Liaw
Summary: Machine learning has become a powerful tool for accurately predicting temperature-dependent yield strengths (YS) of structural materials, especially for multi-principal-element systems. The researchers have developed a bilinear log model that incorporates a break temperature, Tbreak, for predicting temperature-dependent YS of medium-entropy or high-entropy alloys (MEAs or HEAs). This model can guide the design of MEAs or HEAs with attractive high-temperature properties.
APPLIED MATERIALS TODAY
(2023)
Article
Physics, Applied
Rong Hao, Guanhao Liu, Zhong Wang, Huijun Yang, Peter K. Liaw, Junwei Qiao
Summary: This study successfully establishes a model for alloys with low stacking fault energies and predicts their failure threshold. It provides a new approach to further understand the serration mechanism and predict the failure threshold of multicomponent alloys.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Multidisciplinary Sciences
Shuai Chen, Ping Liu, Qingxiang Pei, Zhi Gen Yu, Zachary H. Aitken, Wanghui Li, Zhaoxuan Wu, Rajarshi Banerjee, David J. Srolovitz, Peter K. Liaw, Yong-Wei Zhang
Summary: This study constructs nanolamellar high-entropy alloys and explores their mechanical properties using molecular dynamic simulation and density functional theory calculation. The results show that the nanolamellar structure exhibits ideal plastic behavior and remarkable shape memory effect, highlighting the importance of nanolamellar structures in controlling the mechanical and functional properties of high-entropy alloys.
Article
Chemistry, Physical
Qingwei Guo, Hua Hou, Kaile Wang, Muxi Li, Peter K. Liaw, Yuhong Zhao
Summary: This study proposes a multiparticle model based on molecular dynamics to investigate the coalescence kinetics during the hot-pressed sintering of a polycrystalline high-entropy alloy. The model accurately captures the accelerated occurrences of various phenomena and validates its feasibility by calculating the Young's modulus, which closely matches the experimental value.
NPJ COMPUTATIONAL MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Fusheng Tan, Li Li, Jia Li, Bin Liu, Peter K. Liaw, Qihong Fang
Summary: The harsh environment of nuclear reactors and flaws in existing materials have created a demand for new alloys. High-entropy alloys (HEAs) have gained attention for their potential in nuclear fields. Multiscale modelling has been used to study the irradiated properties of HEAs, deepening understanding and accelerating the development of irradiation-resistant HEAs. This review introduces the state-of-the-art multiscale modelling used for studying the irradiated properties of HEAs and summarizes representative irradiation-induced microstructures, properties, and damage. By strengthening the application of multiscale modelling, the rational design of high irradiation-resistant HEAs is expected.
ADVANCED POWDER MATERIALS
(2023)
