Article
Materials Science, Ceramics
Zhi Qiang Ren, Yu Wei Liu, Ying Liu, Jing Tao Wang
Summary: In this paper, a theoretical formulation for shear transformation zone (STZ) volume, shear band density, and plasticity is presented. The temperature dependence of these parameters is discussed. The experimental data of plasticity for Vit105 bulk metallic glass show negative temperature dependence, which is consistent with the prediction of the analytical formulation.
JOURNAL OF NON-CRYSTALLINE SOLIDS
(2023)
Article
Materials Science, Ceramics
Mohammad Taghi Asadi Khanouki, Rouhollah Tavakoli, Hossein Aashuri
Summary: The study found that the fundamental origin of shear deformation is related to time-dependent structural relaxations occurring at specific temperatures and strain rates. At intermediate temperatures, the localized structural relaxation processes cause inelastic shuffling within cages and mitigate the activation of STZs. Negative strain rate sensitivity at intermediate temperatures is attributed to insufficient time for structural relaxation at high strain rates, resulting in a larger free volume concentration within shear bands and making the BMG softer.
JOURNAL OF NON-CRYSTALLINE SOLIDS
(2021)
Article
Materials Science, Multidisciplinary
Devashish Rajpoot, R. Lakshmi Narayan, Long Zhang, Punit Kumar, Haifeng Zhang, Parag Tandaiya, Upadrasta Ramamurty
Summary: Fracture behavior of bulk metallic glass matrix composites with both transforming and non-transforming fi-Ti dendrites under shear and opening modes was examined, showing lower fracture toughness in mode II due to shear dominant stress state and considerable crack growth in this mode. Despite the ability of transforming dendrites to strain harden and enhance ductility, BMGCs reinforced with non-transforming dendrites exhibit higher toughness in both modes. Shear band patterns suggest identical fracture mechanism in BMGCs and BMGs, with differences rationalized by the effect of relaxation enthalpy and dendrites length scale.
Article
Materials Science, Multidisciplinary
W. H. Zhou, F. H. Duan, Y. H. Meng, C. C. Zheng, H. M. Chen, A. G. Huang, Y. X. Wang, Y. Li
Summary: The study systematically investigated the evolution of microstructure and mechanical properties of Zr-based bulk metallic glasses with varying oxygen content. Results showed that with increasing oxygen content, compressive plasticity decreased slightly before plunging drastically, revealing a threshold oxygen content level for ductile-brittle transition at 3500 at. ppm. The embrittlement at high oxygen content was closely related to changes in microstructure.
Review
Chemistry, Physical
D. Sopu
Summary: The complex nature of shear banding and the disordered structure of metallic glasses pose challenges in understanding the mechanisms of strain localization and shear band formation. The percolation of shear transformation zones (STZs) is widely accepted as the atomic-scale mechanism for shear banding. This review provides an up-to-date assessment of the STZ-Vortex mechanism and its applications in understanding shear band dynamics and deformation mechanisms in metallic glasses. It also highlights unresolved issues where the STZ-Vortex model could be effectively applied.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Multidisciplinary
Siqi Liu, Zexin Chang, Yuequn Fu, Yuyu Liu, Meichao Lin, Xiaobo Ren, Wenxian Wang, Zhiliang Zhang, Jianying He
Summary: This study investigates the nanoscale creep behavior and creep size effect of a selective laser melted Zr-based metallic glass. The results show that the creep resistance decreases with increasing applied peak loads, and a potential mechanism for this creep size effect is proposed.
MATERIALS & DESIGN
(2022)
Article
Chemistry, Physical
J. W. Lv, F. L. Wang, D. W. Yin, S. Zhang, Z. Q. Cai, Z. L. Shi, M. Z. Ma, X. Y. Zhang
Summary: This study investigated the effects of deep cryogenic cycle treatment (DCT) on the microstructure and mechanical behaviors of Ti33Zr30Cu9Ni5.5Be22.5 bulk metallic glass (BMG). The results showed that DCT increased relaxation enthalpy, room-temperature plasticity, and compressive plasticity. The enhancement of plasticity was attributed to the increase in shear transformation zone (STZ) volumes and decrease in shear band formation energy induced by DCT.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Physics, Multidisciplinary
LangTing Zhang, YaJuan Duan, Daniel Crespo, Eloi Pineda, YunJiang Wang, Jean-Marc Pelletier, JiChao Qiao
Summary: Dynamic mechanical relaxation is a fundamental tool for understanding the mechanical and physical properties of viscoelastic materials like glasses. The high-entropy bulk metallic glass exhibits a distinct beta-relaxation feature. Anelastic strain is contributed by the stochastic activation of shear transformation zones (STZs), and interactions between STZs induce viscous-plastic strain under certain conditions.
SCIENCE CHINA-PHYSICS MECHANICS & ASTRONOMY
(2021)
Review
Chemistry, Physical
Michael Atzmon, Jong Doo Ju, Tianjiao Lei
Summary: The lack of periodicity and long-range order in metallic glasses presents significant challenges in explaining their properties. By using quasi-static anelastic relaxation, researchers have obtained relaxation-time spectra for several metallic glasses, enabling them to examine the distribution and properties of shear transformation zones in microscopic detail. The results reveal an atomically-quantized hierarchy of shear transformation zones, providing insights into structural relaxation, plasticity, and the mechanisms of alpha and beta relaxation.
Article
Nanoscience & Nanotechnology
Fu Xu, Yizhou Liu, Botao Dai, Yanhuai Ding, Celal Kursun, Meng Gao
Summary: In this study, an in-situ tensile platform coupled with a nanoindenter was used to investigate the continuous loading and creep behaviors of Cu50Zr50 metallic glass film under different pre-tensile strains. The volume, activation volume, and relaxation time spectrum of shear transformation zones were determined based on models. The results showed that all three factors increase with pre-tensile strain.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Chemistry, Physical
Yuexin Chu, Guishen Zhou, Shaoshan Wan, Yue Zhang, Fuyu Dong, Xiaoguang Yuan, Binbin Wang, Liangshun Luo, Yanqing Su, Weidong Li, Peter K. Liaw
Summary: The relationship between shear transformation zones (STZs) and serrated flow dynamics in metallic glasses (MGs) was analyzed using nanoindentation. Different plasticity MGs were studied, and two distinct types of serrated flow dynamics were identified. MGs with easily activated STZs or low loading rates exhibited a power-law distribution, indicating a self-organized critical state. In contrast, hard MGs or high loading rates showed a Gaussian distribution, indicating a chaotic state with reduced stresses required for plastic deformation.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Engineering, Mechanical
Yucong Gu, Jonathan Cappola, Jian Wang, Lin Li
Summary: This study investigates the yielding behavior of heterogeneous metallic glasses (MGs) by varying the spatial correlation and standard deviation of local shear moduli associated with clustering atoms on the nanoscale. Through computations and observations, the study proposes a Hall-Petch-like relationship where the yield stress of MGs scales inversely with the square root of the spatial correlation length. The results provide insights into the structure-property relationship of MGs and have important implications for the design of nanoscale MGs with tunable properties.
INTERNATIONAL JOURNAL OF PLASTICITY
(2023)
Article
Nanoscience & Nanotechnology
Jianye Shi, Songyun Ma, Shuai Wei, James P. Best, Moritz Stolpe, Bernd Markert
Summary: Selective laser melting is an effective method for producing large-scale bulk metallic glasses, with pore defects considered crucial for mechanical integrity. Through experimental and computational studies, it was found that the ultimate tensile strength of 3D-printed BMGs decreases linearly with increasing porosity, while the Young's modulus remains insensitive at low porosity but decreases rapidly at high porosity levels. Finite element simulations showed different deformation mechanisms for pore-free and pore-containing BMGs, with printing defects playing a dominant role in shear band formation and mechanical properties.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Chemistry, Physical
Xiaojun Sun, Jie He, Dunbo Yu, Yang Luo, Zilong Wang, Yuanfei Yang
Summary: This work investigates the relationship between structural heterogeneity and serrated flow in nanoscale phase separated Zr-Cu-Fe-Al bulk metallic glasses with different plasticity. The results show that as the atomic ratio of Cu to Fe increases, serration dynamics transform from a chaotic state to a self-organized critical state. This transformation is attributed to the increase in structural heterogeneity, which promotes the formation of multiple shear bands.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Multidisciplinary
Huaping Sheng, Long Zhang, Haifeng Zhang, Jianbo Wang, Juergen Eckert, Christoph Gammer
Summary: The transformation-induced plasticity is a fundamental solution for improving the ductility of bulk metallic glass composites (BMGCs). The transformation redistributes the stress in the adjacent matrix, making interfacial regions potential preferential sites for shear band nucleation, which then enhance the ductility of BMGCs.
MATERIALS RESEARCH LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Penghua Ge, Kefu Gan, Dingshun Yan, Pengfei Wu, Weisong Wu, Zhiming Li
Summary: This study reports an anomalous low-temperature annealing-induced hardening behavior in a prototype equiatomic FeCoNi medium-entropy alloy subjected to severe cold-rolling deformation. The hardening phenomenon is confirmed by microhardness measurements and tensile tests, and is correlated with the annealing-modified nanosubgrained structure. The reduction of distribution heterogeneities of shear bands and nanosubgrains upon annealing contributes to the relief of strain localization during plastic yielding. The rearrangement of nanosubgrains upon annealing also relieves the severe heterogeneity of nanohardness distribution, resulting in higher macroscopic strength and hardness. This novel annealing-induced hardening phenomenon provides a guideline for optimizing the thermomechanical treatment strategies of FeCoNi medium-entropy alloys to enhance their mechanical properties.
ADVANCED ENGINEERING MATERIALS
(2023)
Article
Thermodynamics
Chaojun Zhang, Fuyang Cao, Lunyong Zhang, Zhishuai Jin, Guanyu Cao, Ziao Qiu, Hongxian Shen, Yongjiang Huang, Sida Jiang, Jianfei Sun
Summary: This study presents an advanced numerical simulation to explain the mechanism of melt superheat temperature in induction skull melting technology. The coupling model established accurately predicts the temperature and meniscus shape in the research domain. The simulation results reveal that forced convective heat transfer caused by electromagnetic force and the current passing through phenomenon between molten melt and crucible are key factors influencing the superheat temperature and electrical efficiency.
APPLIED THERMAL ENGINEERING
(2023)
Article
Materials Science, Multidisciplinary
Hangboce Yin, Jun-Qiang Wang, Yongjiang Huang, Hongxian Shen, Shu Guo, Hongbo Fan, Juntao Huo, Jianfei Sun
Summary: The new high-entropy metallic-glasses (HE-MGs) are designed using Dy and Ho instead of Gd in the Gd36Tb20Co20Al24 alloy based on the binary eutectic clusters method. The non-equiatomic RE36Tb20Co20Al24 (RE = Gd, Dy, or Ho) alloys show improved glass-forming ability compared to the equiatomic Gd25Tb25Co25Al25 alloy. The Ho36Tb20Co20Al24 alloy exhibits an extreme value of magnetic entropy change, indicating its potential for magnetocaloric applications.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2023)
Article
Engineering, Multidisciplinary
Lei Zhang, Shuang Su, Wujing Fu, Jianfei Sun, Zhiliang Ning, Alfonso H. W. Ngan, Yongjiang Huang
Summary: The structural evolution near the crystalline/matrix interface in CuZr-based metallic glass composite (MGC) was investigated using in situ transmission electron microscope (TEM) tensile straining and molecular dynamics (MD) simulation. Plastic deformation of the crystalline phase occurred before the amorphous phase, involving recoverable martensite transformation, dislocation accumulation at the interface, and local amorphization between grains. Fracture did not occur along the interphase interface, but within the crystalline phase near the interface, indicating a strong interface and high work hardening rate of the crystalline phase. MD simulations revealed that the amorphous phase was marginally metastable compared to the stable B2 phase, while the B19' martensitic phase was metastable with higher energy, explaining the easy mutual transformation between B2 and amorphous phase, and the less frequent transformation product of B19' phase from B2 during straining.
COMPOSITES PART B-ENGINEERING
(2023)
Article
Chemistry, Physical
Wei Yue, Hongbo Fan, Weinan Ru, Zhaoxuan Wu, Zhixiong Zhang, Lunyong Zhang, Zhiliang Ning, Jianfei Sun, Shu Guo, Yongjiang Huang
Summary: Emerging high-entropy alloys (HEAs) exhibit superior mechanical properties due to a synergy of multiple deformation mechanisms and their interactions. In this study, in-situ tensile deformation of a CrMnFeCoNi HEA at room temperature was conducted, revealing the effects of dislocation activity, slip band activation, and interactions on strain hardening rate. The alloy demonstrated high fracture toughness, with cracks initiating at slip zones and grain boundaries and propagating gradually to final fracture.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Nanoscience & Nanotechnology
Lei Zhang, Jianfei Sun, Hongbo Fan, Zhiliang Ning, Yongjiang Huang
Summary: In metallic glass composites (MGCs), the presence of crystalline phases leads to structural heterogeneity in the amorphous matrix near the crystalline phase, resulting in differences in mechanical properties at the micro- or nano-scale near the crystalline/matrix interface. This study quantitatively relates the pile-up height to the activation volume of shear transformation zones (STZs) to characterize this difference using nanoindentation technology. Molecular dynamics simulations were conducted to investigate the activation behaviors of STZs during the nanoindentation process of the amorphous matrix, and the influences of crystalline phases on the deformation behaviors of the amorphous matrix near the interface in MGCs were analyzed in detail.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Engineering, Multidisciplinary
Lei Zhang, Jianfei Sun, Alfonso H. W. Ngan, Zhiliang Ning, Hongbo Fan, Yongjiang Huang
Summary: Amorphous alloy composites (AACs) with reinforcing crystalline phases exhibit superior mechanical properties compared to their base amorphous alloy counterparts. A study on Cu-Zr based AACs reveals that the B2 phase particles embedded in the amorphous matrix are actually heterogeneous at the sub-micron scale, and the amorphous phase exhibits a gradient in free volume content towards the interface. This research provides valuable insights into the crystallization mechanism of the iso-stoichiometric B2 phase in Cu-Zr based AACs.
COMPOSITES PART B-ENGINEERING
(2023)
Article
Chemistry, Physical
Lei Zhang, Hongge Li, Houyi Bai, Zhiliang Ning, Jianfei Sun, Yongjiang Huang
Summary: The structure features of Cu62Zr34.4Al3Nb0.6 amorphous alloy composites (AACs) were studied using experimental characterization and first-principles calculation. Element segregation, a common phenomenon in conventional alloy materials, does not occur in the two phases (crystalline and amorphous) of AACs due to complex solid solution. By calculating different structural models, including interstitial solid solution, substitutional solid solution, B2, and amorphous phase, the lattice parameters, electron distribution, charge transfer, and electrical potential, which are directly related to atomic bonding and lattice parameters, were obtained. Finally, the formation and stability of solid solution in the crystalline and amorphous phases were elucidated using first-principles calculation. This work has important guiding significance for understanding the two-phase structure and solidification mechanism in AACs materials.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Chemistry, Physical
Tianxu Zhao, Songshan Jiang, Qingxin Cui, Xianxue Zhang, Zhiliang Ning, Hongbo Fan, Jianfei Sun, Yongjiang Huang
Summary: In this study, the deformation behaviors of a Cu47.5Zr48Al4Nb0.5 bulk metallic glass composite (BMGC) in the temperature ranging from 663 K to 763 K have been investigated. The studied BMGC exhibits superplasticity within the supercooled liquid region (SLR) and the deformation involves both homogeneous and inhomogeneous modes. The temperature dependence of deformation behaviors in BMGCs was better understood through this study.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Multidisciplinary
Xiaoyu Gao, Jian Liu, Wujing Fu, Yongjiang Huang, Zhiliang Ning, Zhixiong Zhang, Jianfei Sun, Wen Chen
Summary: This study introduces a heterogeneous gradient structure into CoCrFeNi high-entropy alloy microfibers through thermomechanical processing, achieving an excellent combination of high strength and ductility. The microfibers show ultrahigh yield strength and outstanding uniform elongation at low temperatures, thanks to the ultrafine grains, heterogeneous gradient structure, and activation of multiple deformation mechanisms.
MATERIALS & DESIGN
(2023)
Article
Nanoscience & Nanotechnology
Sijia Wang, Jixin Yang, Jianfei Sun, Wenxiang Shu, Haibin Yang, Alfonso H. W. Ngan, Yongjiang Huang
Summary: Here, TA15 samples near alpha titanium alloy were fabricated using electron beam selective melting (EBSM), and their high-temperature tensile deformation behaviors were studied. The results showed that the samples exhibited work hardening and softening at different temperatures, and the EBSM-built TA15 samples had excellent mechanical properties at medium temperatures. These findings are helpful for the industrial applications of EBSM-built titanium alloy components in the aerospace fields.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Nanoscience & Nanotechnology
Sijia Wang, Feiya Guo, Zhiliang Ning, Houyi Bai, Hongge Li, Hongbo Fan, Jianfei Sun, Yongjiang Huang
Summary: This study investigated the structural and tensile deformation behaviors of cold-drawn Cu47.5Zr47.5Al5 amorphous alloy (AA) microwires compared to melt-extracted ones. The results showed that cold-drawn wires still maintained their amorphous structure. The cold-drawing process led to fewer surface defects, higher local order degree, and greater compressive residual stress, resulting in higher tensile fracture strength and reliability compared to melt-extracted ones. This study demonstrated that cold-drawing is an effective method to enhance the mechanical performance of AA wires.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Materials Science, Coatings & Films
Yang Lv, Wei Yue, Zheng Cao, Zhe Zhang, Hongbo Fan, Zhiliang Ning, Jianfei Sun, Peter K. Liaw, Yongjiang Huang
Summary: Laser-shock peening (LSP) is widely used to improve the mechanical properties of metallic components. In this study, the structure and nano-mechanical behaviors of a Ti40Zr25Ni3Cu12Be20 bulk metallic glass (BMG) before and after LSP processing were investigated. The LSP-treated BMG sample remains amorphous, and there is a reduction in local order extent with increasing laser-beam energy, leading to an increase in free-volume contents. The higher free-volume content results in a greater shear-band density and lower nano-hardness in the studied BMG samples.
SURFACE & COATINGS TECHNOLOGY
(2023)
Article
Materials Science, Multidisciplinary
Kefu Gan, Dingshun Yan, Yong Zhang, Pengda Niu
Summary: The effects of added Al element on the nanoindentation behavior of multicomponent alloys were investigated using MD simulation. It was found that the addition of Al changed the structure and plastic behavior of the alloy. The direction of indentation also affected the generation of dislocations and plastic behavior. The results suggested that the composition of the alloy has a strong influence on its mechanical properties.
MATERIALS TODAY COMMUNICATIONS
(2023)
Article
Thermodynamics
Chaojun Zhang, Lunyong Zhang, Fuyang Cao, Zhishuai Jin, Guanyu Cao, Ruishuai Gao, Ziao Qiu, Hongxian Shen, Yongjiang Huang, Jianfei Sun
Summary: This study proposes a full-scale coupling simulation model for understanding the melting process of metallic glass components during induction skull melting (ISM) using finite element method. Through experimental and numerical investigation, the distribution of physical fields and melt homogeneity in the melting process are analyzed.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2024)
