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Keywords = shear band localization

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15 pages, 11276 KiB  
Article
Influence of Casting Texture on Local Material Flow During ECAP of Commercially Pure Aluminum
by Nadja Berndt and Martin Franz-Xaver Wagner
Metals 2025, 15(8), 904; https://doi.org/10.3390/met15080904 - 14 Aug 2025
Viewed by 267
Abstract
The plastic deformation during equal-channel angular pressing (ECAP) can be affected by various material- and processing-related factors. For instance, the initial crystal orientation and grain size play an important role in determining the material flow, which may cause localized deformation in terms of [...] Read more.
The plastic deformation during equal-channel angular pressing (ECAP) can be affected by various material- and processing-related factors. For instance, the initial crystal orientation and grain size play an important role in determining the material flow, which may cause localized deformation in terms of macroscopic deformation banding. In this study, we use a continuous cast AA1080 aluminum alloy with coarse columnar grains to analyze the influence of casting texture on the local material flow during ECAP. Billets are extracted with their columnar grains inclined either in the same direction as the ECAP shear plane or opposite to it. Visio-plastic analysis is performed on split billets. The pass is interrupted halfway through the ECAP tool to accurately capture steady-state deformation conditions. Flow lines at several positions within the billet are identified based on the positions of deformed and undeformed marker points and fitted to a phenomenological model based on a super-ellipse function. For further characterization, hardness measurements, optical and electron microscopy are carried out on the ECAP-deformed samples. Significant differences in terms of local material flow and microstructure evolution regarding the resulting crystal orientation and deformation banding are observed. Our results confirm and emphasize the importance of initial grain size and texture effects for ECAP processing. Full article
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14 pages, 3047 KiB  
Article
Investigation on the Underlying Mechanisms of the Mechanical and Electrical Enhancement of Nano-SiO2-Doped Epoxy Resins: A Molecular Simulation Study
by Kunqi Cui, Yang Wang, Wenchao Yan, Teng Cao, Yan Du, Kai Wu and Li Guo
Molecules 2025, 30(14), 2960; https://doi.org/10.3390/molecules30142960 - 14 Jul 2025
Viewed by 325
Abstract
As a key insulating material in power equipment, epoxy resins (EP) are often limited in practical applications due to space charge accumulation and mechanical degradation. This study systematically investigates the effects of SiO2 nanoparticle doping on the electrical and mechanical properties of [...] Read more.
As a key insulating material in power equipment, epoxy resins (EP) are often limited in practical applications due to space charge accumulation and mechanical degradation. This study systematically investigates the effects of SiO2 nanoparticle doping on the electrical and mechanical properties of SiO2/EP composites through molecular dynamics simulations and first-principles calculations. The results demonstrate that SiO2 doping enhances the mechanical properties of EP, with notable improvements in Young’s modulus, bulk modulus, and shear modulus, while maintaining excellent thermal stability across different temperatures. Further investigations reveal that SiO2 doping effectively modulates the interfacial charge behavior between EP and metals (Cu/Fe) by introducing shallow defect states and reconstructing interfacial dipoles. Density of states analysis indicates the formation of localized defect states at the interface in doped systems, which dominate the defect-assisted hopping mechanism for charge transport and suppress space charge accumulation. Potential distribution calculations show that doping reduces the average potential of EP (1 eV for Cu layer and 1.09 eV for Fe layer) while simultaneously influencing the potential distribution near the polymer–metal interface, thereby optimizing the interfacial charge injection barrier. Specifically, the hole barrier at the maximum valence band (VBM) after doping significantly increased, rising from the initial values of 0.448 eV (Cu interface) and 0.349 eV (Fe interface) to 104.02% and 209.46%, respectively. These findings provide a theoretical foundation for designing high-performance epoxy-based composites with both enhanced mechanical properties and controllable interfacial charge behavior. Full article
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26 pages, 8642 KiB  
Article
Ultra-High Strength and Specific Strength in Ti61Al16Cr10Nb8V5 Multi-Principal Element Alloy: Quasi-Static and Dynamic Deformation and Fracture Mechanisms
by Yang-Yu He, Zhao-Hui Zhang, Yi-Fan Liu, Yi-Chen Cheng, Xiao-Tong Jia, Qiang Wang, Jin-Zhao Zhou and Xing-Wang Cheng
Materials 2025, 18(14), 3245; https://doi.org/10.3390/ma18143245 - 10 Jul 2025
Viewed by 456
Abstract
This study investigates the deformation and fracture mechanisms of a Ti61Al16Cr10Nb8V5 multi-principal element alloy (Ti61V5 alloy) under quasi-static and dynamic compression. The alloy comprises an equiaxed BCC matrix (~35 μm) with uniformly dispersed nano-sized [...] Read more.
This study investigates the deformation and fracture mechanisms of a Ti61Al16Cr10Nb8V5 multi-principal element alloy (Ti61V5 alloy) under quasi-static and dynamic compression. The alloy comprises an equiaxed BCC matrix (~35 μm) with uniformly dispersed nano-sized B2 precipitates and a ~3.5% HCP phase along grain boundaries, exhibiting a density of 4.82 g/cm3, an ultimate tensile strength of 1260 MPa, 12.8% elongation, and a specific strength of 262 MPa·cm3/g. The Ti61V5 alloy exhibits a pronounced strain-rate-strengthening effect, with a strain rate sensitivity coefficient (m) of ~0.0088 at 0.001–10/s. Deformation activates abundant {011} and {112} slip bands in the BCC matrix, whose interactions generate jogs, dislocation dipoles, and loops, evolving into high-density forest dislocations and promoting screw-dominated mixed dislocations. The B2 phase strengthens the alloy via dislocation shearing, forming dislocation arrays, while the HCP phase enhances strength through a dislocation bypass mechanism. At higher strain rates (960–5020/s), m increases to ~0.0985. Besides {011} and {112}, the BCC matrix activates high-index slip planes {123}. Intensified slip band interactions generate dense jogs and forest dislocations, while planar dislocations combined with edge dislocation climb enable obstacle bypassing, increasing the fraction of edge-dominated mixed dislocations. The Ti61V5 alloy shows low sensitivity to adiabatic shear localization. Under forced shear, plastic-flow shear bands form first, followed by recrystallized shear bands formed through a rotational dynamic recrystallization mechanism. Microcracks initiate throughout the shear bands; during inward propagation, they may terminate upon encountering matrix microvoids or deflect and continue when linking with internal microcracks. Full article
(This article belongs to the Special Issue Fatigue, Damage and Fracture of Alloys)
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19 pages, 2791 KiB  
Article
Experimental Investigation of Mechanical Behavior and Damage Evolution of Coal Materials Subjected to Cyclic Triaxial Loads with Increasing Amplitudes
by Zongwu Song, Chun’an Tang and Hongyuan Liu
Materials 2025, 18(13), 2940; https://doi.org/10.3390/ma18132940 - 21 Jun 2025
Viewed by 530
Abstract
As a part of the mining-induced stress redistribution process during coal mining, the repeated loading and unloading process with increasing peak stresses will cause more severe deformation and damage to mining roadways, which is different from the findings in other underground engineering practices. [...] Read more.
As a part of the mining-induced stress redistribution process during coal mining, the repeated loading and unloading process with increasing peak stresses will cause more severe deformation and damage to mining roadways, which is different from the findings in other underground engineering practices. Consequently, cyclic triaxial compression tests with increasing amplitudes were carried out to investigate the mechanical behavior, acoustic emission (AE) characteristics, and damage evolution of coal materials. It is found that peak deviatoric stress and axial residual strain at the failure of coal specimens increase with increasing confining pressures, while the changes in circumferential strain are not obvious. Moreover, the failure patterns of coal specimens exhibit shear failure due to the constraint of confining pressures while some local tensile cracks occur near the shear bands at both ends of the specimens. After that, the damage evolution of coal specimens was analyzed against the regularity of AE counts and energies to develop a damage evolution model. It is concluded that the damage evolution model can not only quantify the deformation and failure process of the coal specimens under cyclic loads with increasing amplitudes but also takes into account both the initial damage due to natural defects and the induced damage by the cyclic loads in previous cycles. Full article
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14 pages, 2451 KiB  
Article
Mechanical and Electronic Properties of Fe(II) Doped Calcite: Ab Initio Calculations
by Zhangci Wu, Xiao Zhi, Fujie Jia, Jiayuan Ye and Neng Li
Crystals 2025, 15(6), 566; https://doi.org/10.3390/cryst15060566 - 16 Jun 2025
Viewed by 345
Abstract
Calcite (CaCO3), a widely used mineral in materials science and environmental engineering, exhibits excellent stability but has limited mechanical strength and a wide electronic band gap, restricting its broader functional applications. To address these limitations, we systematically investigated the effects of [...] Read more.
Calcite (CaCO3), a widely used mineral in materials science and environmental engineering, exhibits excellent stability but has limited mechanical strength and a wide electronic band gap, restricting its broader functional applications. To address these limitations, we systematically investigated the effects of Fe(II) doping on the electronic and mechanical properties of calcite using density functional theory calculations. The results reveal that Fe atoms preferentially form a layered distribution within the lattice and significantly alter the electronic structure, notably reducing the band gap through the introduction of Fe 3d-derived states near the Fermi level. Concurrently, the incorporation of Fe strengthens the elastic constants and enhances the shear resistance, especially in directions aligned with the dopant layering. These improvements are attributed to the strong Fe-O bonding and localized lattice distortions. Furthermore, the interplay between the dopant distribution and magnetic ordering suggests that spin polarization could serve as a potential handle for property tuning. This study highlights Fe-doped calcite as a promising candidate for functional mineral-based materials and provides theoretical insights into the magnetic and structural design of carbonate systems. Full article
(This article belongs to the Special Issue Design and Synthesis of Functional Crystal Materials)
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29 pages, 21376 KiB  
Article
Numerical Simulation of Fracture Failure Propagation in Water-Saturated Sandstone with Pore Defects Under Non-Uniform Loading Effects
by Gang Liu, Yonglong Zan, Dongwei Wang, Shengxuan Wang, Zhitao Yang, Yao Zeng, Guoqing Wei and Xiang Shi
Water 2025, 17(12), 1725; https://doi.org/10.3390/w17121725 - 7 Jun 2025
Cited by 1 | Viewed by 565
Abstract
The instability of mine roadways is significantly influenced by the coupled effects of groundwater seepage and non-uniform loading. These interactions often induce localized plastic deformation and progressive failure, particularly in the roof and sidewall regions. Seepage elevates pore water pressure and deteriorates the [...] Read more.
The instability of mine roadways is significantly influenced by the coupled effects of groundwater seepage and non-uniform loading. These interactions often induce localized plastic deformation and progressive failure, particularly in the roof and sidewall regions. Seepage elevates pore water pressure and deteriorates the mechanical properties of the rock mass, while non-uniform loading leads to stress concentration. The combined effect facilitates the propagation of microcracks and the formation of shear zones, ultimately resulting in localized instability. This initial damage disrupts the mechanical equilibrium and can evolve into severe geohazards, including roof collapse, water inrush, and rockburst. Therefore, understanding the damage and failure mechanisms of mine roadways at the mesoscale, under the combined influence of stress heterogeneity and hydraulic weakening, is of critical importance based on laboratory experiments and numerical simulations. However, the large scale of in situ roadway structures imposes significant constraints on full-scale physical modeling due to limitations in laboratory space and loading capacity. To address these challenges, a straight-wall circular arch roadway was adopted as the geometric prototype, with a total height of 4 m (2 m for the straight wall and 2 m for the arch), a base width of 4 m, and an arch radius of 2 m. Scaled physical models were fabricated based on geometric similarity principles, using defect-bearing sandstone specimens with dimensions of 100 mm × 30 mm × 100 mm (length × width × height) and pore-type defects measuring 40 mm × 20 mm × 20 mm (base × wall height × arch radius), to replicate the stress distribution and deformation behavior of the prototype. Uniaxial compression tests on water-saturated sandstone specimens were performed using a TAW-2000 electro-hydraulic servo testing system. The failure process was continuously monitored through acoustic emission (AE) techniques and static strain acquisition systems. Concurrently, FLAC3D 6.0 numerical simulations were employed to analyze the evolution of internal stress fields and the spatial distribution of plastic zones in saturated sandstone containing pore defects. Experimental results indicate that under non-uniform loading, the stress–strain curves of saturated sandstone with pore-type defects typically exhibit four distinct deformation stages. The extent of crack initiation, propagation, and coalescence is strongly correlated with the magnitude and heterogeneity of localized stress concentrations. AE parameters, including ringing counts and peak frequencies, reveal pronounced spatial partitioning. The internal stress field exhibits an overall banded pattern, with localized variations induced by stress anisotropy. Numerical simulation results further show that shear failure zones tend to cluster regionally, while tensile failure zones are more evenly distributed. Additionally, the stress field configuration at the specimen crown significantly influences the dispersion characteristics of the stress–strain response. These findings offer valuable theoretical insights and practical guidance for surrounding rock control, early warning systems, and reinforcement strategies in water-infiltrated mine roadways subjected to non-uniform loading conditions. Full article
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16 pages, 6146 KiB  
Article
Co-Deformation Process of Cu and Fe Phases in Cu-10Fe Alloy During Cold Rolling
by Wei Chen, Xiaona Hu, Jiawei Wang, Qiuxiang Liu, Dan Wu, Jiang Jiang, Qiang Hu, Deping Lu and Jin Zou
Materials 2025, 18(11), 2547; https://doi.org/10.3390/ma18112547 - 28 May 2025
Viewed by 418
Abstract
Cu-Fe in situ composites often face challenges in achieving high strength during cold rolling due to the inefficient transformation of partial Fe phases into fibrous structures. To uncover the underlying mechanisms, this study systematically investigates the co-deformation behavior of Cu and Fe phases [...] Read more.
Cu-Fe in situ composites often face challenges in achieving high strength during cold rolling due to the inefficient transformation of partial Fe phases into fibrous structures. To uncover the underlying mechanisms, this study systematically investigates the co-deformation behavior of Cu and Fe phases in a Cu-10Fe alloy subjected to cold rolling at various strains. Through microstructure characterization, texture analysis, and mechanical property evaluation, we reveal that the Cu matrix initially accommodates most applied strain (εvm < 1.0), forming shear bands, while Fe phases (dendrites and spherical particles) exhibit negligible deformation. At intermediate strains (1.0 < εvm < 4.0), Fe phases begin to deform: dendrites elongate along the rolling direction, and spherical particles evolve into tadpole-like morphologies under localized shear. Concurrently, dynamic recrystallization occurs near Fe phases in the Cu matrix, generating ultrafine grains. Under high strains (εvm > 4.0), Fe dendrites progressively transform into filaments, whereas spherical Fe particles develop long-tailed tadpole-like structures. Texture evolution indicates that Cu develops a typical copper-type rolling texture, while Fe forms α/γ-fiber textures, albeit with sluggish texture development in Fe. The low efficiency of Fe fiber formation is attributed to the insufficient strength of the Cu matrix and the elongation resistance of spherical Fe particles. To optimize rolled Cu-Fe in situ composites, we propose strengthening the Cu matrix (via alloying/precipitation) and suppressing spherical Fe phases through solidification control. This work provides critical insights into enhancing Fe fiber formation in rolled Cu-Fe systems for high-performance applications. Full article
(This article belongs to the Section Metals and Alloys)
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15 pages, 5752 KiB  
Article
The Influence of Interface Morphology on the Mechanical Properties of Binary Laminated Metal Composites Fabricated by Hierarchical Roll-Bonding
by Yuanyuan Tan, Qingsong Mei and Xu Luo
Metals 2025, 15(6), 580; https://doi.org/10.3390/met15060580 - 23 May 2025
Cited by 1 | Viewed by 488
Abstract
The interface morphology plays an important role in the mechanical properties of laminated metal composites (LMCs). In this study, binary LMCs with different crystallographic characteristics, namely Fe/Al (BCC/FCC), Ni/Al (FCC/FCC), and Mg/Al (HCP/FCC), were fabricated through the hierarchical roll-bonding process. The influence of [...] Read more.
The interface morphology plays an important role in the mechanical properties of laminated metal composites (LMCs). In this study, binary LMCs with different crystallographic characteristics, namely Fe/Al (BCC/FCC), Ni/Al (FCC/FCC), and Mg/Al (HCP/FCC), were fabricated through the hierarchical roll-bonding process. The influence of interface morphology on the mechanical properties of the binary LMCs was investigated systematically. The results show that the strength–hardness coefficient (R) decreases with increasing interface morphology factor (α) for the LMCs, indicating that the strengthening effect of LMCs decreases with increased curvature of the interface. The experimental results reveal that α increases with the increase in rolling deformation (thickness reduction) for the LMCs, which is consistent with the finite element simulation results. The dependence of mechanical properties on interface morphology is mainly related to the microstructural inhomogeneity caused by localized deformation in the harder layer, including the formation of shear bands and variations in grain morphology, size, and orientation, which can lead to stress concentration in the necking zone. Full article
(This article belongs to the Special Issue Research Progress of Crystal in Metallic Materials)
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12 pages, 8658 KiB  
Article
Atomistic Simulation and Micro-Pillar Compression Studies on the Influence of Glass–Glass Interfaces on Plastic Deformation in Co-P Metallic Nano-Glasses
by Yongwei Wang, Jiashu Chen, Mo Li and Guangping Zheng
Materials 2025, 18(8), 1853; https://doi.org/10.3390/ma18081853 - 17 Apr 2025
Viewed by 555
Abstract
The glass–glass interfaces (GGIs) play an important role during the plastic deformation of metallic nano-glasses (NGs) such as Sc-Fe NGs. In this work, Co-P nano-glasses are synthesized by pulse electrodeposition. Their mechanical properties are characterized by micro-pillar compression and compared to those obtained [...] Read more.
The glass–glass interfaces (GGIs) play an important role during the plastic deformation of metallic nano-glasses (NGs) such as Sc-Fe NGs. In this work, Co-P nano-glasses are synthesized by pulse electrodeposition. Their mechanical properties are characterized by micro-pillar compression and compared to those obtained by molecular dynamics (MD) simulation. The MD simulation reveals that the GGIs with a particular incline angle (about 50.0°) in the direction of applied uniaxial strain is preferable for the accommodation of localized plastic deformation in NGs. The results are consistent with those obtained by spherical aberration-corrected transmission electron microscopy, which reveals that most of shear bands form an angle of about 58.7° to the direction of compressive strain applied on the Co-P micro-pillar. The phenomena are explained with the differences in chemical composition and atom diffusion in the glassy grain interiors and in the GGI regions. This work sheds some light on the deformation mechanisms of NGs and provides guidelines for designing NGs with improved mechanical properties. Full article
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25 pages, 15902 KiB  
Article
Analysis of a Summer Convective Precipitation Event in the Shanghai Region Using Data from a Novel Single-Polarization X-Band Phased-Array Radar and Other Meteorological Observations
by Xiaoqiong Zhen, Hongbin Chen, Xuehua Fan, Hongrong Shi, Haojun Chen, Wanyi Wei, Jie Fu, Shuqing Ma, Ling Yang and Jianxin He
Remote Sens. 2025, 17(8), 1403; https://doi.org/10.3390/rs17081403 - 15 Apr 2025
Viewed by 612
Abstract
On 13 August 2019, a severe convective precipitation event affected the Shanghai region. At 850 hPa, a low-level shear line influenced Shanghai with surface convergence, while at 700 hPa, an inversion layer separated warm, moist lower air from colder, drier air aloft, favoring [...] Read more.
On 13 August 2019, a severe convective precipitation event affected the Shanghai region. At 850 hPa, a low-level shear line influenced Shanghai with surface convergence, while at 700 hPa, an inversion layer separated warm, moist lower air from colder, drier air aloft, favoring convection. Observations also revealed vertical wind shear, facilitating additional convective growth. Observations from local automatic weather stations (AWSs) and wind profiler radars (WPRs) indicate that five minutes before rainfall began, ground heat and northerly winds collided, triggering the precipitation. Both the S-band Qingpu SA radar and a novel single-polarization X-band Array weather radar system (Array Weather Radar, AWR) with three phased-array radar frontends and one radar backend captured this event. Compared with the relatively coarse spatiotemporal resolution of the Qingpu SA radar, the AWR provides high-resolution wind-field data, enabling the derivation of horizontal divergence and vertical vorticity. A detailed analysis of reflectivity, divergence, and vorticity in the AWR’s overlapping detection areas shows that, during the development and mature stages of the cell’s lifecycle, the volume of echoes with Z > 25 dBZ consistently increases, whereas echoes with Z > 45 dBZ grow in an oscillatory pattern, reaching five peaks. Moreover, at the altitudes where Z > 45 dBZ appears, regions of cyclonic vorticity emerge. Full article
(This article belongs to the Section Environmental Remote Sensing)
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18 pages, 11277 KiB  
Article
Mechanical Characteristics and Mechanisms of Destruction of Trapezoidal Sandstone Samples Under Uneven Loading
by Bao Pan, Weijian Yu, Ke Li, Zilu Liu, Tao Huang and Jie Yang
Processes 2025, 13(4), 1169; https://doi.org/10.3390/pr13041169 - 12 Apr 2025
Viewed by 447
Abstract
Predicting rock failure under excavation-induced non-uniform stress remains challenging due to the inability of conventional homogeneous specimens to replicate field-scale stress gradients. A novel trapezoidal sandstone specimen with adjustable top-surface inclinations (S75/S85) is proposed, uniquely simulating asymmetric stress gradients to mimic excavation unloading. [...] Read more.
Predicting rock failure under excavation-induced non-uniform stress remains challenging due to the inability of conventional homogeneous specimens to replicate field-scale stress gradients. A novel trapezoidal sandstone specimen with adjustable top-surface inclinations (S75/S85) is proposed, uniquely simulating asymmetric stress gradients to mimic excavation unloading. Geometric asymmetry combined with multi-scale characterization (CT, SEM, PFC) decouples stress gradient effects from material heterogeneity. The key findings include the following points. (1) Inclination angles > 15° reduce peak strength by 24.2%, transitioning failure from brittle (transgranular cracks > 60) to mixed brittle-ductile modes (2) Stress gradients govern fracture pathways: transgranular cracks dominate high-stress zones, while intergranular cracks propagate along weak cementation interfaces. (3) PFC simulations reveal a 147% stress disparity between specimen sides and validate shear localization angles θ = 52° ± 3°), aligning with field data. This experimental–numerical framework resolves limitations of traditional methods, providing mechanistic insights into non-uniform load-driven failure. The methodology enables targeted support strategies for deep asymmetric roadways, including shear band mitigation and plastic zone reinforcement. By bridging lab-scale tests and engineering stress states, the study advances safety and sustainability in deep roadway excavation. Full article
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13 pages, 9649 KiB  
Article
Microstructure Evolution and Mechanical Properties of Dual-Phase AlCrFe2Ni2 High-Entropy Alloy Under High-Strain-Rate Compression
by Hang Yan, Yu Wang, Xilin Gan, Yong Dong, Shichao Liu, Shougang Duan and Lingbo Mao
Materials 2025, 18(6), 1191; https://doi.org/10.3390/ma18061191 - 7 Mar 2025
Viewed by 768
Abstract
This paper investigates the effect of strain rate on the mechanical deformation and microstructural development of dual-phase AlCrFe2Ni2 high-entropy alloy during quasi-static and dynamic compression processes. It is revealed that the as-cast AlCrFe2Ni2 alloy is composed of [...] Read more.
This paper investigates the effect of strain rate on the mechanical deformation and microstructural development of dual-phase AlCrFe2Ni2 high-entropy alloy during quasi-static and dynamic compression processes. It is revealed that the as-cast AlCrFe2Ni2 alloy is composed of a mixture of FCC, disordered BCC, and ordered B2 crystal structure phases. The alloy shows excellent compressive properties under quasi-static and dynamic deformation. The yield strength exceeds 600 MPa while the compressive strength is more than 3000 MPa at the compression rates of 30% under quasi-static conditions. Under dynamic compression conditions, the ultimate compression stresses are 1522 MPa, 1816 MPa, and 1925 MPa with compression strains about 12.8%, 14.7%, and 18.2% at strain rates of 1300 s−1, 1700 s−1 and 2100 s−1, respectively. The dynamic yield strength is approximately linear with strain rate within the specified range and exhibit great sensitivity. The strong localized deformation regions (i.e., adiabatic shear bands (ASBs)) appear in dynamically deformed samples by dynamic recrystallization due to the conflicting processes of strain rate hardening and heat softening. Full article
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13 pages, 6626 KiB  
Article
High Strength–Ductility Synergy of As-Cast B2-Containing AlNbTaTiZr Refractory High-Entropy Alloy Under Intermediate and Dynamic Strain Rates
by Hashim Naseer, Yangwei Wang, Muhammad Abubaker Khan, Jamieson Brechtl and Mohamed A. Afifi
Metals 2025, 15(3), 249; https://doi.org/10.3390/met15030249 - 26 Feb 2025
Cited by 4 | Viewed by 1195
Abstract
Understanding the mechanical behavior of materials under various strain-rate regimes is critical for many scientific and engineering applications. Accordingly, this study investigates the strain-rate-dependent compressive mechanical behavior of B2-containing (TiZrNb)79.5(TaAl)20.5 refractory high-entropy alloy (RHEA) at room temperature. The RHEA is [...] Read more.
Understanding the mechanical behavior of materials under various strain-rate regimes is critical for many scientific and engineering applications. Accordingly, this study investigates the strain-rate-dependent compressive mechanical behavior of B2-containing (TiZrNb)79.5(TaAl)20.5 refractory high-entropy alloy (RHEA) at room temperature. The RHEA is prepared by vacuum arc melting and is tested over intermediate (1.0 × 10−1 s−1, 1.0 s−1) and dynamic (1.0 × 103 s−1, 2.0 × 103 s−1, 2.8 × 103 s−1, 3.2 × 103 s−1, and 3.5 × 103 s−1) strain rates. The alloy characterized as hybrid body-centered-cubic (BCC)/B2 nanostructure reveals an exceptional yield strength (YS) of ~1437 MPa and a fracture strain exceeding 90% at an intermediate (1.0 s−1) strain rate. The YS increases to ~1797 MPa under dynamic strain-rate (3.2 × 103 s−1) loadings, which is a ~25 % improvement in strength compared with the deformation at the intermediate strain rate. Microstructural analysis of the deformed specimens reveals the severity of dislocation activity with strain and strain rate that evolves from fine dislocation bands to the formation of localized adiabatic shear bands (ASBs) at the strain rate 3.5 × 103 s−1. Consequently, the RHEA fracture features mixed ductile–brittle morphology. Overall, the RHEA exhibits excellent strength–ductility synergy over a wide strain-rate domain. The study enhances understanding of the strain-rate-dependent mechanical behavior of B2-containing RHEA, which is significant for alloy processes and impact resistance applications. Full article
(This article belongs to the Special Issue Structure and Properties of Refractory Medium/High-Entropy Alloys)
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12 pages, 5712 KiB  
Communication
The Strain Heterogeneity and Microstructural Shear Bands in AZ31B Magnesium Alloy
by Qinghui Zhang, Xuhui Zhang, Xiaojuan Yang and Min Huang
Appl. Sci. 2025, 15(3), 1571; https://doi.org/10.3390/app15031571 - 4 Feb 2025
Viewed by 823
Abstract
In this study, the strain distribution and microstructural evolution of the AZ31B magnesium alloy were analyzed via uniaxial tensile loading combined with an in situ tensile test. The results conclusively showed that the strain on the AZ31B magnesium alloy’s surface is not uniform [...] Read more.
In this study, the strain distribution and microstructural evolution of the AZ31B magnesium alloy were analyzed via uniaxial tensile loading combined with an in situ tensile test. The results conclusively showed that the strain on the AZ31B magnesium alloy’s surface is not uniform during tensile loading in a specific direction, and the emergence of localized twins fosters the development of densely intersecting shear bands, whereas prismatic slip intensified the strain concentration within these bands, ultimately bolstering their strength. These densely packed, discrete shear bands exhibited a dual role: they stabilized plastic deformation processes while simultaneously contributing to material failure. By elucidating the intricate relationship between grain orientation, evolution of the microstructure, and mechanical properties, we could effectively mitigate the detrimental orientations and deformations in anisotropic-polycrystalline materials to enhance their plasticity. The research carries paramount scientific significance and is the key to maximizing the engineering application potential of the AZ31B magnesium alloy. Full article
(This article belongs to the Section Additive Manufacturing Technologies)
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20 pages, 4822 KiB  
Article
Networking 3 K Two-Qubit Logic Gate Quantum Processors to Approach 1 Billion Logic Gate Performance
by Daniel Guidotti, Xiaoli Ma and Gee-Kung Chang
Electronics 2024, 13(23), 4604; https://doi.org/10.3390/electronics13234604 - 22 Nov 2024
Viewed by 1155
Abstract
Outlined is a proposal designed to culminate in the foundry fabrication of arrays of singly addressable quantum dot sources deterministically emitting single pairs of energy-time entangled photons at C-band wavelengths, each pair having negligible spin-orbit fine structure splitting, each pair being channeled into [...] Read more.
Outlined is a proposal designed to culminate in the foundry fabrication of arrays of singly addressable quantum dot sources deterministically emitting single pairs of energy-time entangled photons at C-band wavelengths, each pair having negligible spin-orbit fine structure splitting, each pair being channeled into single mode pig-tail optical fibers. Entangled photons carry quantum state information among distributed quantum servers via I/O ports having two functions: the unconditionally secure distribution of decryption keys to decrypt publicly distributed, encrypted classical bit streams as input to generate corresponding qubit excitations and to convert a stream of quantum nondemolition measurements of qubit states into a classical bit stream. Outlined are key steps necessary to fabricate arrays of on-demand quantum dot sources of entangled photon pairs; the principles are (1) foundry fabrication of arrays of isolated quantum dots, (2) generation of localized sub-surface shear strain in a semiconductor stack, (3) a cryogenic anvil cell, (4) channeling entangled photons into single-mode optical fibers, (5) unconditionally secure decryption key distribution over the fiber network, (6) resonant excitation of a Josephson tunnel junction qubits from classical bits, and (7) conversion of quantum nondemolition measurements of qubit states into a classical bit. Full article
(This article belongs to the Special Issue Advances in Signals and Systems Research)
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