Article
Physics, Applied
X. Y. Gong, X. D. Wang, P. Zhang, X. Z. Cao, Q. P. Cao, D. X. Zhang, J. Z. Jiang
Summary: Structural rejuvenation of bulk metallic glasses (BMGs) using electropulsing treatment (EPT) was studied in this paper. It was found that voltages below 110 V had little rejuvenation effect on BMGs, while discharging at 130 V significantly reduced density, modulus, and hardness while generating more excess free volume. The changes in properties of EPT samples were consistent with variations in total content and average size of free volume, providing an efficient way to alter the structure and properties of BMGs.
APPLIED PHYSICS LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Zhen-Ya Zhou, Qing Chen, Yang Sun, Hai-Bin Yu
Summary: The alpha(2) relaxation identified in metallic glasses influences the yielding behaviors of the materials, providing an additional way to control their mechanical properties. The transition from stress overshoot to nonovershoot yielding is related to the same time-temperature relation and microscopic origin of the alpha(2) relaxation.
Article
Chemistry, Physical
Lili Ma, Jianing Wang, Zhangheng Lai, Zhichao Wu, Baiting Yang, Panpan Zhao
Summary: A series of Fe-free Al56-xCo24Cr20Nix (x = 34, 36, 38, 40, and 42) eutectic high-entropy alloys were designed and prepared to study the influence of Al and Ni content on microstructure and mechanical properties. The results revealed that all the alloys exhibited a typical eutectic microstructure and an ordered FCC/BCT phase structure. Increasing Ni content led to a reduction in the volume fraction of the BCT phase. The Ni38 alloy showed an unsatisfactory tensile property due to irregular eutectic lamellas, while the Ni38.5 alloy with a regularly and fine lamellar hypereutectic microstructure exhibited improved fracture strain without compromising yield strength.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Multidisciplinary Sciences
Deng Pan, Teng Ji, Matteo Baggioli, Li Li, Yuliang Jin
Summary: This study investigates the effects of nonlinear elasticity on the mechanical and thermodynamic properties of amorphous materials responding to shear using holographic duality and gravitational theories. The predicted correlations between the nonlinear elastic exponent, yielding strain/stress, and entropy change due to shear are qualitatively supported by simulations. This research opens up new possibilities for understanding the complex mechanical responses of amorphous solids and studying the rheology of solid states and black holes in a unified framework.
Article
Nanoscience & Nanotechnology
S. H. Chen, J. S. Zhang, S. Guan, T. Li, J. Q. Liu, F. F. Wu, Y. C. Wu
Summary: This study prepared WNbMoTaZrx (x = 0.1, 0.3, 0.5, 1.0) refractory high entropy alloys (RHEAs) and characterized their microstructure, hardness, compressive properties, and fracture behavior. The results showed that increasing Zr content improved the mechanical properties of the RHEAs, primarily due to solid solution strengthening, formation of interdendritic regions, and refinement of dendrite structures. The deformation mechanisms and fracture modes of RHEAs with higher compressive plasticity were examined and discussed.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Nanoscience & Nanotechnology
Baiting Yang, Lili Ma, Panpan Zhao
Summary: A Co-free Bx(CrFeNi)100-x (x = 0, 0.25, 0.5, 1.0, 1.5, 2.0, 3.0, 4.5, and 6 at%) medium-entropy alloys (MEAs) system was designed to investigate the effect of boron (B) content on the microstructure and mechanical properties. The addition of B element promoted the improvement of yield strength but caused a reduction in elongation. B0.25 alloy exhibited an improvement in yield strength and a slight decline in elongation after cold rolling and recrystallization annealing. These findings provide insights for the design and optimization of MEAs for structural applications.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Materials Science, Multidisciplinary
Santhosh Mathesan, Dan Mordehai
Summary: In molecular dynamics simulations of nanoporous gold nanopillars, non-linear deformation characteristics, stress plateau, and hardening stage are observed. The load-bearing capacity is maintained by unyielded ligaments, contributing to stress increase. Coalescence of ligaments plays a dominant role in hardening during compression.
COMPUTATIONAL MATERIALS SCIENCE
(2021)
Article
Chemistry, Physical
Wei Qu, Yuan Hou, Wei Li, Yubao Liu, Lei Xing, Huiping Ren
Summary: This study demonstrated an effective approach for the secondary phase precipitation of La0.005Al0.17FeCoCrNiMn HEAs by rapid solidification and aging treatment. The control of precipitated phases formation achieved precipitation strengthening for high-entropy alloys.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Nanoscience & Nanotechnology
Zhenhua Han, Lingkun Meng, Jun Yang, Gang Liu, Jungang Yang, Ran Wei, Guojun Zhang
Summary: The refractory V-Nb-Ta alloys with single BCC structure exhibited excellent combination of strength and plasticity, which was attributed to the solid solution strengthening effect caused by the large atomic size misfit among Nb, Ta and V elements.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Physics, Fluids & Plasmas
Shiheng Cui, Huashan Liu, Hailong Peng
Summary: In this study, computer simulations were conducted to investigate the shear deformation of CuZr metallic glasses at different temperatures. The results reveal the emergence of shear bands at a specific strain point in athermal alloys, and the presence of a finite-size effect. The correlation of nonaffine displacement shows an exponential decay in thermal alloys even after yielding, whereas it transitions to a power law in athermal alloys at a certain strain point.
Article
Chemistry, Physical
Ran Wei, Zhen Jiang, Qiuyu Gao, Chen Chen, Kaisheng Zhang, Suo Zhang, Zhenhua Han, Shaojie Wu, Tan Wang, Fushan Li
Summary: This study investigated the microstructure, mechanical properties, and corrosion resistance of Fe50Mn25Cr15Ni10-xCox medium-entropy alloys. The results showed that the microstructure and properties of the alloys changed with increasing Co concentration, affecting their mechanical strength, ductility, and corrosion resistance.
Article
Multidisciplinary Sciences
Florian Spieckermann, Daniel Sopu, Viktor Soprunyuk, Michael B. Kerber, Jozef Bednarcik, Alexander Schokel, Amir Rezvan, Sergey Ketov, Baran Sarac, Erhard Schafler, Juergen Eckert
Summary: In-situ X-ray diffraction is used to study structural rearrangements during annealing processes in Cu44Zr-44Al8Hf2Co2 bulk metallic glass. The deformation-induced rejuvenation reveals a structural footprint that can be correlated to calorimetric signals, showing characteristics of a first-order transition for the beta-transition. Dynamic mechanical analysis data indicates that non-reversible structural rearrangements are preferentially activated during the beta-transition, while reversible deformations dominate the low-temperature alpha-transition with second-order characteristics.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Physical
Z. Y. You, Z. Y. Tang, F. B. Chu, L. Ma, G. F. Guan, H. Ding, R. D. K. Misra
Summary: This study systematically investigated the microstructure and mechanical properties of a tri-phase heterogeneous high-entropy alloy (HEA) under different thermo-mechanical processing. The HEA exhibited a hierarchical microstructure and showed varying mechanical properties depending on the recrystallized fraction. Multiple strengthening mechanisms were activated during deformation, leading to an increase in work hardening rate. The phase distribution and recrystallized grains morphology were characterized, providing insights into the synergy between strength and ductility in HEAs.
Article
Polymer Science
Yanxu Wang, Shaopeng Chen, Tong Wu, Qiang Fu
Summary: This work systematically investigates the deformation mechanisms of isotactic polypropylene (iPP) precursor films prepared under different supercooling conditions during stretching at elevated temperatures. Three deformation mechanisms, namely inter-spherulitic, intra-spherulitic, and mix deformation, were observed as the yielding stress changed with stretching temperature. The transition temperature (60 degrees C) correlates closely with the α2 relaxation of iPP, which activates chain diffusion within the crystal blocks. The competition between inter-spherulitic deformation and intra-spherulitic deformation is determined not only by the spherulite structures but also by the stretching temperatures. Further studies reveal that larger spherulite size, more daughter lamellae, and lower stretching temperature dominate the induction of inter-spherulitic deformation. This work is expected to guide the preparation of iPP films with desired structures and functionalities.
Article
Nanoscience & Nanotechnology
Hiroyuki Y. Yasuda, Yusuke Yamada, Ken Cho, Takeshi Nagase
Summary: The deformation behavior of equiatomic HfNbTaTiZr high entropy alloy was found to be influenced by 1/2<111> screw dislocations, similar to body centered cubic metals. An anomaly in yield stress was observed in the alloy solutionized at 1473 K, with the stress decreasing rapidly at lower temperatures and increasing at 873 K. The microstructure of the alloy strongly depended on annealing temperature, with phase separation and precipitation of different phases observed at different temperatures. Dynamic precipitation of the HCP phase was suggested to be responsible for the yield stress anomaly.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Engineering, Mechanical
Zhuang Sun, Yixin Zhao, Yirui Gao, Sen Gao, Davide Elmo, Xindong Wei
Summary: In this study, the modified semi-circular bending test was used to investigate the fracture toughness of coal samples with different sizes and bedding angles. The results showed that the fracture toughness of coal exhibits size effect and anisotropy. The crack initiation and propagation in hydraulic fracturing of coal seam can be influenced by bedding angles.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Ruiming Zhang, Kai Ma, Wenzhu Peng, Jinyang Zheng
Summary: The fatigue crack growth rates of 4130X steel in different hydrogen concentrations were measured, and the influence of hydrogen on crack behavior was analyzed. Results show that the crack growth rate increases with increasing hydrogen pressure, reaching a threshold at 87.5 MPa.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Hien Do, Phuc L. H. Ho, Canh V. Le, H. Nguyen-Xuan
Summary: In this study, a new method for determining the limit loads of fracture structures using the pseudo-lower bound method with adaptive quadtree meshes is proposed. The method overcomes the volumetric locking problem and handles the challenge of hanging nodes during refinement procedure by using quadtree meshes. The effectiveness of the approach is demonstrated through numerical validation.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Weimin Song, Yuxin Fan, Hao Wu, Liang Zhou
Summary: This study proposed a novel test method to characterize the I-II mixed fracture toughness of asphalt pavement and investigated the effects of reclaimed asphalt pavement (RAP) and loading rate. The results showed that loading rate and inclusion of RAP had positive effects on fracture toughness.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Zida Liu, Diyuan Li, Jianqiang Xia, Quanqi Zhu
Summary: In this study, the influence of flaw inclinations on the failure mechanism of fissured granite specimens was analyzed through a series of experiments. A quantitative method combining deep learning and scanning electron microscope was employed to identify the mesoscopic fracture mechanism of macroscopic cracks. The results indicated that the failure of fissured specimens was mainly caused by tensile stress and shear stress.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Jiabing Zhang, Yiling Chen, Ronghuan Du, Xianglian Zhao, Jun Wu
Summary: This study investigated the mechanical characteristics and crack propagation behavior of sandstone-like samples with single cracks under freeze-thaw cycles. The results demonstrated the significant effects of crack angle and freeze-thaw cycles on the compressive strength and stability of the samples. Confining pressure inhibited the freeze-thaw deterioration, and the acoustic emission signals exhibited good consistency with the stress-strain curves. The simulation results matched well with the experimental results, and five crack propagation modes were proposed.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Felix Boedeker, Pauline Herr, Anders Biel, Ramin Moshfegh, Stephan Marzi
Summary: Cohesive Zone Models with finite thickness are widely used for fracture mechanical modeling. Computational homogenization techniques are crucial for the development of advanced engineering materials. FFT-based homogenization scheme shows potential in reducing computational effort and has practical applications.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Sobhan Pattajoshi, Sonalisa Ray, Yugal Kishor Joshi
Summary: In this work, a novel multi-layer composite structure is proposed for protective shelter design. The dynamic behavior and mechanical performance of the multi-layer composite under projectile impact loading are investigated. The proposed composite target demonstrates enhanced penetration resistance and lesser damage compared to its reinforced concrete monolayer counterpart. An analytical model is also developed to predict the forces transmitted to the lowest layer for design purposes.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
H. M. Shodja, M. T. Kamali, B. Shokrolahi-Zadeh
Summary: This study proposes a semi-analytical method for calculating the stress intensity factor of an internally pressurized eccentric annular crack. By using hypersingular integral equations and conformal mapping, accurate values of SIFs along the crack edges can be obtained. The material properties of the elastic matrix do not affect the SIF values, as demonstrated through the investigation of geometric parameters.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Wen Hua, Zhanyuan Zhu, Wenyu Zhang, Jianxiong Li, Jiuzhou Huang, Shiming Dong
Summary: Accurate assessment and prediction of fracture behavior in cracked materials using mixed mode fracture criteria are crucial in fracture mechanics. This study comprehensively reviewed modified fracture criteria that incorporate T-stress for mixed mode I-II cracks. A comparative analysis was conducted between experimental results and theoretical predictions for five different cracked configurations. The study also discussed the effect of T-stress on crack initiation angle and fracture toughness, providing suggestions. The results showed variations in predictive accuracy across different cracked configurations due to disparities in T-stress. However, similar predictions were observed for semi-circular bend and edge-crack triangular specimens due to their similar biaxial stress ratio B. Different fracture criteria were suitable for different cracked configurations with positive or negative T-stresses.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Qing-qing Shen, Qiu-hua Rao, Wei Yi, Dian-yi Huang
Summary: This study proposes a theoretical approach to forecast multi-crack propagation trajectories in a finite plate. By calculating the stress intensity factor (SIF) and analyzing the influence of crack size, the criteria for crack initiation and propagation in a finite plate are established. Experimental results demonstrate that the SIF of multiple cracks in a finite plate is consistently larger than that of an infinite plate.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Songbai Li, Qiyun Zhu, Zhizhong Lu, Hongzhi Yan, Chu Zhu, Peize Li
Summary: This study investigates the effects of laser heating and laser shot peening on fatigue life of AA2524, and predicts the fatigue life using artificial neural networks and support vector regression models. The results show that laser heating and laser shot peening can significantly improve the fatigue life, and the neural networks have better prediction ability.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
V. Shlyannikov, A. Sulamanidze, D. Kosov
Summary: This paper presents experimental crack-growth data for thermomechanical fatigue conditions in nickel-based alloy components. The crack-growth experimental results are interpreted using finite element analyses and multi-physics numerical calculations. The results show that crack growth rate is slower under isothermal pure fatigue conditions, while it is faster under thermomechanical cyclic deformation conditions.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Tairui Zhang, Xin Ma, Bin Yang, Wenchun Jiang, Zhiqiang Ge, Xiaochao Liu
Summary: This study experimentally investigated the fracture toughness distributions in dissimilar metal welds. The predictions of fracture toughness were made using three criteria and an energy release rate model. The results showed that using the critical strain criterion and ERR model resulted in higher consistency compared to mini-CTs, while the predictions using the critical stress criterion had high dispersion. The study also investigated the source of errors through damage developments and SEM observations.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Yike Dang, Zheng Yang, Xiaoyu Liu, Jianghao Guo
Summary: This study uses discrete element modeling to examine bedded rock failure with parallel defects. It is found that bedding influences crack propagation direction but has limited impact on final failure. Shear failure accumulates at the bridge area and defect tip, while tensile failure occurs during nucleation region development.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)