Article
Materials Science, Multidisciplinary
Tangqing Cao, Qian Zhang, Liang Wang, Lu Wang, Yao Xiao, Jiahao Yao, Huaiyi Liu, Yang Ren, Jun Liang, Yunfei Xue, Xiaoyan Li
Summary: High-entropy alloys (HEAs) possess unique microstructures and chemical compositions, resulting in remarkable mechanical properties. In this study, the mechanical behaviors and deformation mechanisms of CoCrFeNi HEAs under dynamic loading were investigated through experiments and simulations. The results showed significant strain rate sensitivity and strain-hardening capability of CoCrFeNi HEAs at high strain rates. The findings shed light on the design and fabrication of HEAs with excellent dynamic mechanical properties.
Article
Materials Science, Multidisciplinary
Ravi Sankar Haridas, Priyanka Agrawal, Surekha Yadav, Priyanshi Agrawal, Anurag Gumaste, Rajiv S. Mishra
Summary: The excellent work hardening in TRIP-enabled metastable high entropy alloys is attributed to the phase transformation from austenite to martensite, as well as non-basal slip activity and deformation twinning. A five-parameter empirical model has been developed to replicate the work hardening rate in TRIP HEAs, with easy parameter identification compared to physically based models. The model parameters are correlated with stacking fault energy to predict the tensile stress-strain response of TRIP HEAs.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2022)
Article
Nanoscience & Nanotechnology
Xiaocan Wen, Li Zhu, Muhammad Naeem, Hailong Huang, Suihe Jiang, Hui Wang, Xiongjun Liu, Xiaobin Zhang, Xun-Li Wang, Yuan Wu, Zhaoping Lu
Summary: Decreasing the Nb content in TiZrHfNbTa0.2 high-entropy alloys (HEAs) allows for multiple deformation mechanisms, such as dislocation planar slip, strain-induced phase transformations, and twinning, at a cryogenic temperature of 77 K. The TiZrHfNb0.3Ta0.2 HEA exhibits exceptional strain hardening capability and high uniform elongation of about 25% without ductile-brittle transition.
SCRIPTA MATERIALIA
(2023)
Article
Engineering, Mechanical
William M. Williams, Mitra Shabani, Paul D. Jablonski, Garrett J. Pataky
Summary: CoCrFeNi alloy exhibits good steady-state fatigue crack growth resistance at room temperature, with the plastic deformation mechanism transitioning from dislocation slip to the addition of nano-twinning as crack life progresses.
INTERNATIONAL JOURNAL OF FATIGUE
(2021)
Article
Materials Science, Multidisciplinary
Zheng Tian, Jianjun Wang, Shengguo Ma, Li Qiao, Zhihua Wang
Summary: The compression behavior of high-entropy alloys (HEAs) is influenced by the microstructure and strain rate, with solid-solution strengthening, phase precipitation hardening, and phonon drag effect playing key roles. The dynamic deformation process is characterized by grain refinement and nanoscale twins, while quasistatic loading results in dislocation substructures and deformation twinning for work hardening.
ADVANCED ENGINEERING MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
Jongun Moon, Olivier Bouaziz, Hyoung Seop Kim, Yuri Estrin
Summary: Deformation-induced twinning was used as a strengthening mechanism in a thermomechanical treatment for a high-entropy alloy, resulting in improved mechanical properties, especially in strain hardening ability, at room temperature.
SCRIPTA MATERIALIA
(2021)
Article
Nanoscience & Nanotechnology
Jongun Moon, Olivier Bouaziz, Hyoung Seop Kim, Yuri Estrin
Summary: By utilizing low-temperature pre-straining and subsequent annealing, the mechanical properties of CoCrFeMnNi high-entropy alloy were improved, confirming the effectiveness of twinning engineering concept.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Nanoscience & Nanotechnology
S. Picak, H. C. Yilmaz, I Karaman
Summary: High temperature equal channel angular pressing (ECAP) was used to activate simultaneous twinning-induced (TWIP) and transformation-induced plasticity (TRIP) in the CoCrFeMnNi high entropy alloy (HEA), resulting in a high strength level and uniform plastic deformation ability. This phenomenon was attributed to the high strength levels applied via ECAP and the relatively low stacking fault energy of the present HEA.
SCRIPTA MATERIALIA
(2021)
Article
Materials Science, Multidisciplinary
Yongju Kim, Hyung Keun Park, Peyman Asghari-Rad, Jaimyun Jung, Jongun Moon, Hyoung Seop Kim
Summary: The constitutive modeling of CoCrFeMnNi high-entropy alloy at cryogenic and room temperatures has been investigated, showing enhanced ductility and strength at 77K due to the combination of sub-grain structure, twinning, and dislocations. A kinematic constitutive model with a critical twinning stress parameter was constructed to explain the twinning initiation criteria, showing good agreement with experimental data. Different modeling parameters were obtained for each temperature to account for the changing deformation behavior.
METALS AND MATERIALS INTERNATIONAL
(2021)
Article
Chemistry, Physical
Mingao Li, Shulong Xiao, Lijuan Xu, Jing Tian, Yuyong Chen
Summary: The study shows that dispersive perovskite-Ti3AlC can strengthen TiAl alloys and contribute to better plastic deformation and elongation in high niobium containing TiAl alloys. Transmission electron microscopy and high-resolution transmission electron microscopy reveal the dislocation gliding and twinning mechanism during plastic deformation, as well as the relationship between perovskite-Ti3AlC and the neighboring matrix phase.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Nanoscience & Nanotechnology
Xutao Wang, Liang Wang, Tianxiang Li, Ke Jin, Benpeng Wang, Yunkai Li, Shihai Sun, Yunfei Xue
Summary: Strain softening upon dynamic loading is a roadblock for BCC structured HEAs, but in this study, precipitation of alpha 2 phase was applied to enhance strain hardening capability. The alpha 2 precipitates with BOR interface effectively reduce slip length and generate high density dislocations for hardening.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Nanoscience & Nanotechnology
Y. Z. Wang, Z. M. Jiao, G. B. Bian, H. J. Yang, H. W. He, Z. H. Wang, P. K. Liaw, J. W. Qiao
Summary: Face-centered-cubic (FCC) Fe40Mn20Cr20Ni20 high-entropy alloys (HEAs) were fabricated by industrialized vacuum-induction melting and formed a heterogenous structure consisting of a phase distribution and grain size after thermomechanical treatments. Under dynamic tension, the alloy showed simultaneous enhancements in strength and ductility due to the activation of multiple strengthening mechanisms. This study provides new insights for developing high-performance HEAs to resist dynamic impacts.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Engineering, Mechanical
Yunjian Bai, Kun Zhang, Tianyu Chen, Zishang Liu, Yunjiang Wang, Bingchen Wei
Summary: The study explores the origin of TCA and its impact on work hardening in high-entropy alloys, highlighting the interactions between dislocations and stacking faults as key contributors to TCA. The differences in behavior between tension and compression are attributed to the FCC/BCC alternating lamellar heterostructure, with potential for tuning TCA through structural adjustments.
INTERNATIONAL JOURNAL OF PLASTICITY
(2022)
Article
Materials Science, Multidisciplinary
Shunhui Luo, Tuanwei Zhang, Hui Chang, Shiyu Du, Zhiming Jiao, Renlong Xiong, Hyoung Seop Kim, Zhihua Wang
Summary: This research achieved the precipitation of the primary Ni16Ti6Si7 intermetallic, the secondary large-sized L12 phase, and the tertiary diffused distributed nanoscale L12 particles in an aged Ni2CoCr0.5Si0.3Al0.2Ti0.2 medium entropy alloy. The alloy exhibited high strength, good ductility, and excellent work hardening rate. The synergistic strengthening mechanisms, including dislocation Orowan mechanisms and shearing effects, were identified, providing insights for the design of high-performance precipitation-strengthened alloys.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
Article
Chemistry, Physical
Aliakbar Emdadi, Oleg Stryzhyboroda, Ulrike Hecht, Markus Bambach
Summary: The current research provides scientific evidence that the complex softening processes involving dynamic recovery, dynamic recrystallization, and twinning contribute efficiently to the hot deformation processing of the Al0.5CoCrFeNi alloy. The study identifies the optimal processing window for this alloy and reveals the microstructural changes that occur during deformation. The findings highlight the potential for refining the microstructure through the combination of twinning and dynamic recrystallization.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Materials Science, Multidisciplinary
Heng Duan, Bin Liu, Ao Fu, Junyang He, Tao Yang, C. T. Liu, Yong Liu
Summary: This study successfully prepared a FeCrNi medium entropy alloy with ultrahigh Cr content using SLM technology, showing excellent mechanical properties and corrosion resistance mainly attributed to the stable passive film formed by a large number of cell boundaries.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2022)
Article
Nanoscience & Nanotechnology
Yueling Guo, Junyang He, Zhiming Li, Lina Jia, Xiaoxiang Wu, Changmeng Liu
Summary: Introducing intermetallic silicides into refractory high entropy alloys can significantly improve their mechanical properties, especially at high temperatures. Si alloying enables grain refinement and the formation of intergranular silicides, resulting in improved compressive strength and deformation compatibility of the alloy.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
Zening Wang, Yu Yan, Yuan Wu, Yanjing Su, Lijie Qiao
Summary: The repassivation behavior of equiatomic TiZr (Hf, Ta, Nb) alloys was studied. It was found that TiZrHf had the highest repassivation rate, while TiZrNb had the highest coefficient of friction and wear rate. Tribofilm and material transfer were observed in all medium entropy alloys.
Article
Nanoscience & Nanotechnology
Fan Zhang, Junyang He, Yuan Wu, Huahai Mao, Hui Wang, Xiongjun Liu, Suihe Jiang, T. G. Nieh, Zhaoping Lu
Summary: The morphology and volume fraction of precipitates play crucial roles in the mechanical properties of precipitation-hardened HEAs. This study investigated the effects of Ni and Al on the precipitation behavior and mechanical properties of (FeCoCr)(98-x-y)NixTi2Aly (x = 25, 30, 35; y = 4, 6, 8) HEAs. It was found that increasing Ni and Al content promotes the formation of coherent γ' precipitates, but also leads to the appearance of an incoherent Heusler phase. The ratio of Ni to Al was found to be pivotal in the formation of the Heusler phase, and when the ratio exceeds 5, the Heusler phase can be completely eliminated. The findings provide valuable insights for the optimal design of precipitation-hardened HEAs and contribute to the understanding of precipitation behavior in highly concentrated alloys.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
Zhengqi Wang, Honghui Wu, Yuan Wu, Hailong Huang, Xiangyu Zhu, Yingjie Zhang, Huihui Zhu, Xiaoyuan Yuan, Qiang Chen, Shudao Wang, Xiongjun Liu, Hui Wang, Suihe Jiang, Moon J. Kim, Zhaoping Lu
Summary: In this study, large plasticity and high strength were achieved in NbMoTaW RHEAs through grain boundary engineering and the addition of metalloid B or C. The room-temperature brittleness of as-cast NbMoTaW RHEA was found to be caused by grain boundary segregation of oxygen, which was alleviated by the added metalloids, leading to a change in fracture morphology.
Article
Chemistry, Physical
Jinlong Du, Suihe Jiang, Peipei Cao, Chuan Xu, Yuan Wu, Huaqiang Chen, Engang Fu, Zhaoping Lu
Summary: This study reports a strategy to achieve high radiation tolerance at high temperatures. By enabling the disordering-ordering transition of nanoprecipitates in metallic materials, the radiation damage can be prevented, leading to improved radiation tolerance.
Article
Materials Science, Multidisciplinary
Jing Peng, Jia Li, Bin Liu, Jian Wang, Haotian Chen, Hui Feng, Xin Zeng, Heng Duan, Yuankui Cao, Junyang He, Peter K. Liaw, Qihong Fang
Summary: Additive manufacturing is believed to open a new era in precise microfabrication. This study investigates the microstructure evolution of a prototype multi-principal-element alloy FeCrNi fabricated using selective laser melting (SLM) through experiment and simulation. The results reveal the growth of columnar crystals across cladding layers and the development of dense cellular structures in the filled crystal. At the micron scale, the constituent elements are evenly distributed, while at the near-atomic scale, segregation of Cr element is observed. Simulation results demonstrate changes in the solid-liquid interface and the formation of precipitates, microscale voids, and stacking faults due to the thermal gradient, resulting in residual stress in the SLMed structure. A microstructure-based physical model reveals the presence of strong interface strengthening in tensile deformation.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2023)
Article
Materials Science, Multidisciplinary
Shenglong Liang, Yihan Wang, Hui Wang, Jun Wang, Suihe Jiang
Summary: A simple-yet-powerful processing method, involving multi-pass proper annealing following medium-strain cold-rolling deformation, was successfully applied to a Bi-containing brass alloy. The method led to simultaneous improvements in both strength and ductility of the alloy, mainly due to the redistribution of the bulky Bi phase and the grain refinement of the brass matrix.
Article
Materials Science, Multidisciplinary
Junyang He, Rui Wang, Na Li, Zhongrun Xiao, Ji Gu, Hongyao Yu, Zhongnan Bi, Weihong Liu, Min Song
Summary: Through multi-scale characterizations from electron channeling contrast imaging to atom probe tomography, we have directly demonstrated that the massive cracking events in selective-laser-melted Haynes 230 superalloy are caused by the continuous decoration of an M(23)C(6-)type thin film at grain boundaries. Despite being strongly depleted from the carbide, impurities Si, Mn, and Fe greatly enhance the susceptibility to cracking.
MATERIALS RESEARCH LETTERS
(2023)
Article
Chemistry, Physical
Wentian Chen, Yufan Wu, Lin Guo, Ji Gu, Junyang He, Min Song
Summary: This study investigated the comprehensive effects of carbon doping on the recrystallization process and mechanical performance of the Cantor alloy during mid-temperature annealing. The presence of M23C6 carbides in the early stage of recrystallization accelerates the process by providing nucleation sites. The coarsening and migration of these carbides in the later stage suppresses the overall recrystallization process.
Article
Chemistry, Physical
Longjun Li, Li Wang, Zhida Liang, Junyang He, Min Song
Summary: The formation of various types of oxide scales on the surface and along the grain boundaries of a complex CoNi-based superalloy was investigated at 900 degrees C. A complex multilayered oxide scale was formed under steady-state conditions (oxidation time up to 24 hours). After the breakdown of the steady-state oxide scale (oxidation for 48 hours), different types of oxide scales occurred. It was also observed that oxidation gradually extended into the specimen interior along the grain boundaries, caused by selective oxidation of elements due to differences in equilibrium oxygen partial pressures. Local microstructure and oxygen concentration were found to significantly influence the formation and configuration of the oxide scales in the investigated alloy.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Chemistry, Physical
Jiabin Yu, Hui Wang, Xiongjun Liu, Suihe Jiang, Xiaobin Zhang, Guoliang Xie, Dong He, Lei Shao, Pan Zhang, Yingjie Zhang, Jinfeng Huang, Yuan Wu, Zhaoping Lu
Summary: This study investigated the combustion behaviors of NiCo-based medium-entropy alloys (MEAs) with face-centred-cubic (FCC) structures in high-pressure oxygen atmospheres using a specially designed experimental apparatus. The flame-retardant performances of these alloys were comparable to those of traditional superalloys, and the flame-retardant mechanism was explored through thermodynamic and kinetic analysis. The study also examined the effects of key elements, such as Cr, Ni, Co, and Mn, on the combustion behaviors. The findings enhance our understanding of the flame-retardant mechanism of FCC structured medium-entropy alloys and provide guidelines for designing alloys with satisfactory flame-retardant performances.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Nanoscience & Nanotechnology
Weijin Cai, Junyang He, Li Wang, Wenchao Yang, Xiangqi Xu, Khurram Yaqoob, Zhangwei Wang, Min Song
Summary: This study investigates the chemical short-range order (CSRO) in VCoNi medium-entropy alloy (MEA) processed by spark plasma sintering (SPS) and hot-rolling (HR). The SPS-HRed MEA exhibits a sharp increase in strength compared to the cast counterpart, attributed to the presence of dislocations, stacking faults, nano-twins, and V-oxide particles. Despite differences in microstructure and thermal routes, the CSRO in the SPS-HRed MEA shows a similar L11-type structure motif and sub-nanometer size. The preference of V-Co and avoidance of V-V pairs are observed, while the preference of V-Ni pair disappears due to the varying matrix composition.
SCRIPTA MATERIALIA
(2023)
Article
Materials Science, Multidisciplinary
Bo Peng, Hui Wang, Min Zhou, Ren Zhang, Xinting Li, Jun Wu, Guangpeng Xu, Lixin Zhou, Haotian Dong, Suihe Jiang, Zhaoping Lu
SCIENCE CHINA-MATERIALS
(2023)
Article
Urology & Nephrology
Sano Takanori, Nobuyuki Hinata, Ryoya Kobayashi, Tatsuya Nakatsuji, Yasuyoshi Okamura, Junya Furukawa, Yuzo Nakano, Toshiji Mukai, Masato Fujisawa
Summary: We developed a bioabsorbable metal alloy and found that it has good degradability and no stone adhesion. It was safely used in animal experiments.
WORLD JOURNAL OF UROLOGY
(2023)