Pub Date : 2025-02-21DOI: 10.1016/j.jnoncrysol.2025.123420
S.D. Wansi Wendji , R. Piotrowski , C. Massobrio , M. Boero , C. Tugène , F. Shuaib , D. Hamani , P.-M. Geffroy , P. Thomas , A. Bouzid , O. Masson , G. Delaizir , G. Ori
Structural and bonding insights into sodium vanadium phosphate (NVP) glasses are crucial for optimizing their performance as cathode materials in sodium-ion batteries. This study quantitatively assesses the structural features and bonding characteristics of two NVP glass compositions: (NaO)–(VO)–(PO) with 0.375, 0.285. We combine experimental characterization (differential scanning calorimetry, X-ray diffraction and X-ray photoelectron spectroscopy,) and atomistic modeling (classical molecular dynamics (CMD), and Born–Oppenheimer molecular dynamics (BOMD)). This work provides a quantitative analysis of the different VO units in the two NVP glass models, superseding previous knowledge based largely on CMD simulations. Our results show that the account of the electronic structure, inherent in BOMD simulations is essential for capturing the VO bonding environment. This includes the splitting of the VO peak in the pair distribution function due to both short VO and longer VO bonds, a higher degree of polymerization in the phosphate network and a more significant role for V as a network former.
{"title":"Enhanced structural description of sodium vanadium phosphate glasses: A combined experimental and molecular dynamics study","authors":"S.D. Wansi Wendji , R. Piotrowski , C. Massobrio , M. Boero , C. Tugène , F. Shuaib , D. Hamani , P.-M. Geffroy , P. Thomas , A. Bouzid , O. Masson , G. Delaizir , G. Ori","doi":"10.1016/j.jnoncrysol.2025.123420","DOIUrl":"10.1016/j.jnoncrysol.2025.123420","url":null,"abstract":"<div><div>Structural and bonding insights into sodium vanadium phosphate (NVP) glasses are crucial for optimizing their performance as cathode materials in sodium-ion batteries. This study quantitatively assesses the structural features and bonding characteristics of two NVP glass compositions: (Na<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>O)<span><math><msub><mrow></mrow><mrow><mi>α</mi></mrow></msub></math></span>–(V<span><math><msub><mrow></mrow><mrow><mi>x</mi></mrow></msub></math></span>O<span><math><mi>y</mi></math></span>)<span><math><msub><mrow></mrow><mrow><mrow><mo>(</mo><mn>1</mn><mo>−</mo><mn>2</mn><mi>α</mi><mo>)</mo></mrow></mrow></msub></math></span>–(P<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>O<span><math><msub><mrow></mrow><mrow><mn>5</mn></mrow></msub></math></span>)<span><math><msub><mrow></mrow><mrow><mi>α</mi></mrow></msub></math></span> with <span><math><mrow><mi>α</mi><mo>=</mo></mrow></math></span> 0.375, 0.285. We combine experimental characterization (differential scanning calorimetry, X-ray diffraction and X-ray photoelectron spectroscopy,) and atomistic modeling (classical molecular dynamics (CMD), and Born–Oppenheimer molecular dynamics (BOMD)). This work provides a quantitative analysis of the different VO<span><math><msub><mrow></mrow><mrow><mi>n</mi></mrow></msub></math></span> units in the two NVP glass models, superseding previous knowledge based largely on CMD simulations. Our results show that the account of the electronic structure, inherent in BOMD simulations is essential for capturing the V<img>O bonding environment. This includes the splitting of the V<img>O peak in the pair distribution function due to both short V<img>O and longer V<img>O bonds, a higher degree of polymerization in the phosphate network and a more significant role for V<span><math><msup><mrow></mrow><mrow><mn>5</mn><mo>+</mo></mrow></msup></math></span> as a network former.</div></div>","PeriodicalId":16461,"journal":{"name":"Journal of Non-crystalline Solids","volume":"655 ","pages":"Article 123420"},"PeriodicalIF":3.2,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143454835","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-19DOI: 10.1016/j.jnoncrysol.2025.123450
Kandasamy Vignarooban, Charles Skipper, Aaron Welton, Punit Boolchand
Raman scattering and calorimetric measurements on lithium borate, (Li2O)x(B2O3)100-x, and sodium borate, (Na2O)x(B2O3)100-x, glasses, 0 < x < 45 %, were undertaken to elucidate the role of glass molecular structure on the topological phases and melt dynamics. For (Na2O)x(B2O3)100-x glasses, a wide square-well like variation of the enthalpy of relaxation at the glass transition was observed, showing an intermediate phase (IP) in the 20 % < x < 40 % range of soda. Raman results reveal the IP to be correlated with the existence of six unique Isostatically Rigid Local Structures (ISRLSs) which have characteristic ring morphologies appearing sequentially with increasing soda concentration across the IP. Additionally, several narrowly defined Gaussian-like fragility index, m, minima are observed to manifest in the 15 < m < 20 range, which appear sequentially with increasing mol x% and directly correspond to the stoichiometry of the six molecular ring based ISRLS. Parallel results are observed for (Li2O)x(B2O3)100-x.
{"title":"Linking the ring-morphology of (Li2O)x(B2O3)100-x and (Na2O)x(B2O3)100-x borate glasses with topological phases and melt dynamics","authors":"Kandasamy Vignarooban, Charles Skipper, Aaron Welton, Punit Boolchand","doi":"10.1016/j.jnoncrysol.2025.123450","DOIUrl":"10.1016/j.jnoncrysol.2025.123450","url":null,"abstract":"<div><div>Raman scattering and calorimetric measurements on lithium borate, (Li<sub>2</sub>O)<sub>x</sub>(B<sub>2</sub>O<sub>3</sub>)<sub>100-x</sub>, and sodium borate, (Na<sub>2</sub>O)<sub>x</sub>(B<sub>2</sub>O<sub>3</sub>)<sub>100-x</sub>, glasses, 0 < <em>x</em> < 45 %, were undertaken to elucidate the role of glass molecular structure on the topological phases and melt dynamics. For (Na<sub>2</sub>O)<sub>x</sub>(B<sub>2</sub>O<sub>3</sub>)<sub>100-x</sub> glasses, a wide square-well like variation of the enthalpy of relaxation at the glass transition was observed, showing an intermediate phase (IP) in the 20 % < <em>x</em> < 40 % range of soda. Raman results reveal the IP to be correlated with the existence of six unique <u>I</u>sostatically <u>R</u>igid <u>L</u>ocal <u>S</u>tructures (ISRLSs) which have <em>characteristic ring morphologies</em> appearing <em>sequentially with increasing soda concentration across the IP.</em> Additionally, several narrowly defined Gaussian-like fragility index, <em>m</em>, minima are observed to manifest in the 15 < <em>m</em> < 20 range, which appear <em>sequentially with increasing mol x%</em> and directly correspond to the <em>stoichiometry of the six molecular ring based ISRLS</em>. Parallel results are observed for (Li<sub>2</sub>O)<sub>x</sub>(B<sub>2</sub>O<sub>3</sub>)<sub>100-x</sub>.</div></div>","PeriodicalId":16461,"journal":{"name":"Journal of Non-crystalline Solids","volume":"654 ","pages":"Article 123450"},"PeriodicalIF":3.2,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143437218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-19DOI: 10.1016/j.jnoncrysol.2025.123436
Yuezhou Luo, Andrew John Flewitt
Multiple trapping and release (MTR) is a typical charge transport mechanism associated with localized states in technologically important disordered semiconductors such as hydrogenated amorphous silicon (a-Si:H) and many amorphous oxides. However, till now the analysis of MTR has been built on an “abrupt” mobility edge model. Using electron transport as an example, the abrupt mobility edge model assumes that: (i) states above the conduction band (CB) mobility edge (EC) are extended and any of them is omnipresent in space, whereas states below EC are localized and they exist in the energy-space diagram as pointlike sites; (ii) all states are evenly distributed in space. The prequel to this paper [Y. Luo and A. Flewitt, Phys. Rev. B 109, 104203 (2024)] demonstrates that neither of these simplifications is valid. Hence, this paper reinvestigates MTR transport. Through a probabilistic analysis of the microscopic charge transport details, this paper rigorously achieves two critical conclusions that challenge previous beliefs. First, the mobility edge, which is characterizable through activation energy measurement of conductivity, is an effective quantity associated with carrier relaxation dynamics; it does not demarcate the extended states and localized states of an amorphous semiconductor. Second, the extended-state mobility, which is extractable from time-of-flight experiments, is also an effective quantity that is higher than the mobility of free carriers in the material.
{"title":"Revisiting multiple trapping and release charge transport in amorphous semiconductors exemplified by hydrogenated amorphous silicon","authors":"Yuezhou Luo, Andrew John Flewitt","doi":"10.1016/j.jnoncrysol.2025.123436","DOIUrl":"10.1016/j.jnoncrysol.2025.123436","url":null,"abstract":"<div><div>Multiple trapping and release (MTR) is a typical charge transport mechanism associated with localized states in technologically important disordered semiconductors such as hydrogenated amorphous silicon (<em>a</em>-Si:H) and many amorphous oxides. However, till now the analysis of MTR has been built on an “abrupt” mobility edge model. Using electron transport as an example, the abrupt mobility edge model assumes that: (i) states above the conduction band (CB) mobility edge (<em>E<sub>C</sub></em>) are extended and any of them is omnipresent in space, whereas states below <em>E<sub>C</sub></em> are localized and they exist in the energy-space diagram as pointlike sites; (ii) all states are evenly distributed in space. The prequel to this paper [Y. Luo and A. Flewitt, Phys. Rev. B <strong>109</strong>, 104203 (2024)] demonstrates that neither of these simplifications is valid. Hence, this paper reinvestigates MTR transport. Through a probabilistic analysis of the microscopic charge transport details, this paper rigorously achieves two critical conclusions that challenge previous beliefs. First, the mobility edge, which is characterizable through activation energy measurement of conductivity, is an effective quantity associated with carrier relaxation dynamics; it does not demarcate the extended states and localized states of an amorphous semiconductor. Second, the extended-state mobility, which is extractable from time-of-flight experiments, is also an effective quantity that is higher than the mobility of free carriers in the material.</div></div>","PeriodicalId":16461,"journal":{"name":"Journal of Non-crystalline Solids","volume":"654 ","pages":"Article 123436"},"PeriodicalIF":3.2,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143446078","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-19DOI: 10.1016/j.jnoncrysol.2025.123444
Ephraim Bryski, Kedar Kirane
This paper examines the statistical variation in the mechanical behavior of amorphous silica using molecular dynamics (MD) simulations. The variability arises from random initial atomic arrangements in replicate samples. Reactive molecular dynamics (R-MD) with the ReaxFF–SiO force field was used to simulate 100 samples, each prepared via a melt-quench process to ensure unique atomic configurations, but identical radial distribution functions. Uniaxial tension simulations on uncracked and pre-cracked samples were carried out to predict properties such as elastic modulus, strength, strain to failure, and fracture energy. Results show that initial atomic configurations significantly influence mechanical properties, introducing statistical variation that follows a normal distribution, consistent with the central limit theorem. The normal distribution of strength suggests that amorphous silica exhibits ductile-like failure at the nanoscale, despite brittle behavior macroscopically. Identifying the mean and standard deviation of these distributions enables quantification of variability in MD predictions, enhancing the reliability and understanding of such simulations.
{"title":"Statistical variability in mechanical properties of amorphous silica predicted by molecular dynamics","authors":"Ephraim Bryski, Kedar Kirane","doi":"10.1016/j.jnoncrysol.2025.123444","DOIUrl":"10.1016/j.jnoncrysol.2025.123444","url":null,"abstract":"<div><div>This paper examines the statistical variation in the mechanical behavior of amorphous silica using molecular dynamics (MD) simulations. The variability arises from random initial atomic arrangements in replicate samples. Reactive molecular dynamics (R-MD) with the ReaxFF–SiO force field was used to simulate 100 samples, each prepared via a melt-quench process to ensure unique atomic configurations, but identical radial distribution functions. Uniaxial tension simulations on uncracked and pre-cracked samples were carried out to predict properties such as elastic modulus, strength, strain to failure, and fracture energy. Results show that initial atomic configurations significantly influence mechanical properties, introducing statistical variation that follows a normal distribution, consistent with the central limit theorem. The normal distribution of strength suggests that amorphous silica exhibits ductile-like failure at the nanoscale, despite brittle behavior macroscopically. Identifying the mean and standard deviation of these distributions enables quantification of variability in MD predictions, enhancing the reliability and understanding of such simulations.</div></div>","PeriodicalId":16461,"journal":{"name":"Journal of Non-crystalline Solids","volume":"655 ","pages":"Article 123444"},"PeriodicalIF":3.2,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143436557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-19DOI: 10.1016/j.jnoncrysol.2025.123451
Chunghee Nam
This study applies deep learning to predict Vickers hardness in bulk metallic glasses (BMGs) using limited datasets, addressing key challenges in materials informatics. Leveraging a convolutional neural network (CNN) model based solely on compositional features, we bypass traditional feature selection. Trained on 418 BMG samples across 10 cross-validation subsets, the model achieved strong predictive performance, with a peak R² score of 0.983 and RMSE of 55.814 in the CV3 subset, highlighting the CNN's ability to capture composition-property relationships. Validation on unseen compositions confirmed the model's robustness, closely matching experimental values. Additionally, a pseudo-ternary diagram for Zr-Al-Co alloys was constructed, visually mapping composition to hardness. This work underscores the viability of CNNs for small datasets, advancing data-driven methods for BMG hardness prediction and materials design.
{"title":"Convolutional neural network-based prediction of hardness in bulk metallic glasses with small data","authors":"Chunghee Nam","doi":"10.1016/j.jnoncrysol.2025.123451","DOIUrl":"10.1016/j.jnoncrysol.2025.123451","url":null,"abstract":"<div><div>This study applies deep learning to predict Vickers hardness in bulk metallic glasses (BMGs) using limited datasets, addressing key challenges in materials informatics. Leveraging a convolutional neural network (CNN) model based solely on compositional features, we bypass traditional feature selection. Trained on 418 BMG samples across 10 cross-validation subsets, the model achieved strong predictive performance, with a peak R² score of 0.983 and RMSE of 55.814 in the CV<sub>3</sub> subset, highlighting the CNN's ability to capture composition-property relationships. Validation on unseen compositions confirmed the model's robustness, closely matching experimental values. Additionally, a pseudo-ternary diagram for Zr-Al-Co alloys was constructed, visually mapping composition to hardness. This work underscores the viability of CNNs for small datasets, advancing data-driven methods for BMG hardness prediction and materials design.</div></div>","PeriodicalId":16461,"journal":{"name":"Journal of Non-crystalline Solids","volume":"654 ","pages":"Article 123451"},"PeriodicalIF":3.2,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143446079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-18DOI: 10.1016/j.jnoncrysol.2025.123447
Manjiang Li , Jianfeng Zhang , Haimeng Huang , Gaiye Li , Lei Liu , Jun Wang , Yahui Liu
Hollow glass microspheres (HGMs) are lightweight fillers with significant potential in various applications, including oil drilling, deep-sea exploration, and aerospace. This study introduces a mathematical model with adaptive thermal boundary conditions to examine the effects of cooling medium, particle size, and wall thickness on the temperature gradient and residual stress distribution in HGMs. Results indicate that using water as a quenching medium results in the fastest cooling rates and the highest residual stress. HGMs are rapidly quenched when using water as the cooling medium, resulting in a compressive strength range of approximately 30–53 %. Smaller particle sizes and thicker walls positively affect compressive strength by improving heat dissipation and increasing the temperature gradient within the material. However, non-uniform wall thickness of individual HGMs induces stress concentration, significantly weakening material strength. Therefore, optimizing heating and cooling rates, while ensuring uniform particle characteristics, is crucial for improving the durability and performance of HGMs.
{"title":"Numerical simulation of temperature and stress field distribution during the rapid quenching process of hollow glass microspheres","authors":"Manjiang Li , Jianfeng Zhang , Haimeng Huang , Gaiye Li , Lei Liu , Jun Wang , Yahui Liu","doi":"10.1016/j.jnoncrysol.2025.123447","DOIUrl":"10.1016/j.jnoncrysol.2025.123447","url":null,"abstract":"<div><div>Hollow glass microspheres (HGMs) are lightweight fillers with significant potential in various applications, including oil drilling, deep-sea exploration, and aerospace. This study introduces a mathematical model with adaptive thermal boundary conditions to examine the effects of cooling medium, particle size, and wall thickness on the temperature gradient and residual stress distribution in HGMs. Results indicate that using water as a quenching medium results in the fastest cooling rates and the highest residual stress. HGMs are rapidly quenched when using water as the cooling medium, resulting in a compressive strength range of approximately 30–53 %. Smaller particle sizes and thicker walls positively affect compressive strength by improving heat dissipation and increasing the temperature gradient within the material. However, non-uniform wall thickness of individual HGMs induces stress concentration, significantly weakening material strength. Therefore, optimizing heating and cooling rates, while ensuring uniform particle characteristics, is crucial for improving the durability and performance of HGMs.</div></div>","PeriodicalId":16461,"journal":{"name":"Journal of Non-crystalline Solids","volume":"654 ","pages":"Article 123447"},"PeriodicalIF":3.2,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143437324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-16DOI: 10.1016/j.jnoncrysol.2025.123443
Yerin Jo , Yonggeun Choi , Hyosoon Shin , Moonhee Choi , Donghun Yeo , Youngwoo Heo
Solid electrolytes for secondary batteries offer advantages over liquid ones, enhancing application range and scalability. While oxide-based solid electrolytes are actively researched for all-solid-state batteries, studies on the atmospheric stability of lithium borosilicate (LBS) glass are limited. Notably, LBS glass green sheets show significant changes in mechanical properties under varying humidity. This study investigates the aging of LBS glass materials, both as powder and green sheets, in controlled humid environments. Analysis using thermal gravimetric analysis-differential thermal analysis (TG-DTA), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR) revealed that moisture evaporation and crystal formation occur over time. Both forms reacted with atmospheric H₂O, forming new crystal structures, especially under high humidity. In conclusion, LBS glass undergoes structural and chemical changes due to humidity and time, highlighting the importance of considering environmental conditions in practical applications.
{"title":"Effects of storage humidity on the crystal structure and on the sheet properties of the lithium borosilicate glass for solid electrolyte","authors":"Yerin Jo , Yonggeun Choi , Hyosoon Shin , Moonhee Choi , Donghun Yeo , Youngwoo Heo","doi":"10.1016/j.jnoncrysol.2025.123443","DOIUrl":"10.1016/j.jnoncrysol.2025.123443","url":null,"abstract":"<div><div>Solid electrolytes for secondary batteries offer advantages over liquid ones, enhancing application range and scalability. While oxide-based solid electrolytes are actively researched for all-solid-state batteries, studies on the atmospheric stability of lithium borosilicate (LBS) glass are limited. Notably, LBS glass green sheets show significant changes in mechanical properties under varying humidity. This study investigates the aging of LBS glass materials, both as powder and green sheets, in controlled humid environments. Analysis using thermal gravimetric analysis-differential thermal analysis (TG-DTA), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR) revealed that moisture evaporation and crystal formation occur over time. Both forms reacted with atmospheric H₂O, forming new crystal structures, especially under high humidity. In conclusion, LBS glass undergoes structural and chemical changes due to humidity and time, highlighting the importance of considering environmental conditions in practical applications.</div></div>","PeriodicalId":16461,"journal":{"name":"Journal of Non-crystalline Solids","volume":"654 ","pages":"Article 123443"},"PeriodicalIF":3.2,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143421742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-16DOI: 10.1016/j.jnoncrysol.2025.123449
Li Fan, Yifan Yang, Jing Geng, Sailong Zhang, Yunwei Cao, Bo Shi
We report a gradient metallic glass (MG) prepared based on stress driven spatially non-uniform dynamics. When elastostatic loading is applied to the MG with ultra-low aspect ratio, strongly lateral constraints can lead to a triaxial compressive stress region, resulting in a non-uniform stress field throughout the entire sample. Thereupon atoms in different regions of the sample will undergo asynchronous evolution, ultimately forming a gradient structure. The experimental results reveal that the energy state and mechanical properties of the gradient MG exhibit a gradient distribution. The molecular dynamics (MD) simulation indicates that triaxial compressive stress induces a quantity of uniform plastic events. Meanwhile, triaxial compressive stress also causes the changes of local atomic configurations: the decreases of the densely packed icosahedral clusters with high fivefold symmetry and of the potential barrier for plastic events. This work provides new insights for the macro heterogeneous design and the toughening of MGs.
{"title":"Mechanical properties of gradient metallic glass induced by spatially non-uniform dynamics","authors":"Li Fan, Yifan Yang, Jing Geng, Sailong Zhang, Yunwei Cao, Bo Shi","doi":"10.1016/j.jnoncrysol.2025.123449","DOIUrl":"10.1016/j.jnoncrysol.2025.123449","url":null,"abstract":"<div><div>We report a gradient metallic glass (MG) prepared based on stress driven spatially non-uniform dynamics. When elastostatic loading is applied to the MG with ultra-low aspect ratio, strongly lateral constraints can lead to a triaxial compressive stress region, resulting in a non-uniform stress field throughout the entire sample. Thereupon atoms in different regions of the sample will undergo asynchronous evolution, ultimately forming a gradient structure. The experimental results reveal that the energy state and mechanical properties of the gradient MG exhibit a gradient distribution. The molecular dynamics (MD) simulation indicates that triaxial compressive stress induces a quantity of uniform plastic events. Meanwhile, triaxial compressive stress also causes the changes of local atomic configurations: the decreases of the densely packed icosahedral clusters with high fivefold symmetry and of the potential barrier for plastic events. This work provides new insights for the macro heterogeneous design and the toughening of MGs.</div></div>","PeriodicalId":16461,"journal":{"name":"Journal of Non-crystalline Solids","volume":"654 ","pages":"Article 123449"},"PeriodicalIF":3.2,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143421741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-16DOI: 10.1016/j.jnoncrysol.2025.123438
Xudong Yuan , Long Zhang , Tingyi Yan , Huameng Fu , Hongwei Zhang , Hong Li , Haifeng Zhang
Metallic glass composites (MGCs) with an amorphous-crystalline dual-phase structure can display remarkable mechanical properties. However, the cooperative deformation mechanisms of both phases and the shear band (SB) evolution in MGCs still remain elusive. In this work, the deformation behaviors of MGCs containing phase-transformable or dislocation-mediated crystals are thoroughly investigated by molecular dynamics simulations. It is found that the SB dynamics can be significantly altered by the stress concentration caused by notches and the deformation characteristics of the crystals. Notch-induced stress redistribution can enhance the shear-band blunting degree and promote the formation of multiple SBs, which highly delocalize the plastic deformation of the phase-transformable MGCs and optimize their ductility. In comparison, introducing notches cannot alter the highly localized shear banding mechanism in the dislocation-mediated MGCs. These findings deepen the atomic-level understanding of the cooperative deformation mechanisms of both phases and the SB evolution in MGCs.
{"title":"Shear-band evolution and plasticity enhancement of metallic glass composites investigated by molecular dynamics simulations","authors":"Xudong Yuan , Long Zhang , Tingyi Yan , Huameng Fu , Hongwei Zhang , Hong Li , Haifeng Zhang","doi":"10.1016/j.jnoncrysol.2025.123438","DOIUrl":"10.1016/j.jnoncrysol.2025.123438","url":null,"abstract":"<div><div>Metallic glass composites (MGCs) with an amorphous-crystalline dual-phase structure can display remarkable mechanical properties. However, the cooperative deformation mechanisms of both phases and the shear band (SB) evolution in MGCs still remain elusive. In this work, the deformation behaviors of MGCs containing phase-transformable or dislocation-mediated crystals are thoroughly investigated by molecular dynamics simulations. It is found that the SB dynamics can be significantly altered by the stress concentration caused by notches and the deformation characteristics of the crystals. Notch-induced stress redistribution can enhance the shear-band blunting degree and promote the formation of multiple SBs, which highly delocalize the plastic deformation of the phase-transformable MGCs and optimize their ductility. In comparison, introducing notches cannot alter the highly localized shear banding mechanism in the dislocation-mediated MGCs. These findings deepen the atomic-level understanding of the cooperative deformation mechanisms of both phases and the SB evolution in MGCs.</div></div>","PeriodicalId":16461,"journal":{"name":"Journal of Non-crystalline Solids","volume":"654 ","pages":"Article 123438"},"PeriodicalIF":3.2,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143421739","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-15DOI: 10.1016/j.jnoncrysol.2025.123442
Ivette Angarita , Ma. Florencia Mazzobre , Horacio R. Corti , Ma. Paula Longinotti
The effect of confinement on the melting and glass transition (Tg) temperatures of tetraethylene glycol (TREG) aqueous solutions was studied in bulk and confined in mesoporous silica over a range of TREG weight fractions (wTREG) from 0.30 to 0.99.
For bulk solutions Tg shows a constant value for wTREG = 0.90–0.99, which was explained considering that the addition of water to the polyol increases the size of the α relaxing entities. For wTREG = 0.50–0.90, Tg decreases with increasing water content due to the plasticizer effect of water. In contrast, for wTREG = 0.30–0.40, Tg values increase, reaching a constant value independent of the water content. This is explained by the fact that, in these dilute systems, water can crystallize during cooling the samples before the heating scan. Hence, the glassy phase attains the composition of the maximally freeze concentrated solution.
The behavior of Tg with composition for samples confined in pores with diameters ranging from 8 to 58 nm is similar to that observed in bulk. However, in pores with 2 nm diameter, Tg exhibits a different behavior. Tg decreases with water content in the composition range wTREG = 0.90–0.99, indicating that the size of the α relaxing entities should be between 2 and 8 nm. For wTREG = 0.30–0.40, Tg also attains a constant value indicating that water also crystallizes in 2 nm pore samples when cooling them before the heating scans.
{"title":"Solid-liquid equilibrium and glass transition temperatures of tetraethylene glycol – water mixtures in bulk and confined mesoporous silica","authors":"Ivette Angarita , Ma. Florencia Mazzobre , Horacio R. Corti , Ma. Paula Longinotti","doi":"10.1016/j.jnoncrysol.2025.123442","DOIUrl":"10.1016/j.jnoncrysol.2025.123442","url":null,"abstract":"<div><div>The effect of confinement on the melting and glass transition (<em>T</em><sub>g</sub>) temperatures of tetraethylene glycol (TREG) aqueous solutions was studied in bulk and confined in mesoporous silica over a range of TREG weight fractions (<em>w</em><sub>TREG</sub>) from 0.30 to 0.99.</div><div>For bulk solutions <em>T<sub>g</sub></em> shows a constant value for <em>w</em><sub>TREG</sub> = 0.90–0.99, which was explained considering that the addition of water to the polyol increases the size of the <em>α</em> relaxing entities. For <em>w</em><sub>TREG</sub> = 0.50–0.90, <em>T<sub>g</sub></em> decreases with increasing water content due to the plasticizer effect of water. In contrast, for <em>w</em><sub>TREG</sub> = 0.30–0.40, <em>T<sub>g</sub></em> values increase, reaching a constant value independent of the water content. This is explained by the fact that, in these dilute systems, water can crystallize during cooling the samples before the heating scan. Hence, the glassy phase attains the composition of the maximally freeze concentrated solution.</div><div>The behavior of <em>T<sub>g</sub></em> with composition for samples confined in pores with diameters ranging from 8 to 58 nm is similar to that observed in bulk. However, in pores with 2 nm diameter, <em>T<sub>g</sub></em> exhibits a different behavior. <em>T<sub>g</sub></em> decreases with water content in the composition range <em>w</em><sub>TREG</sub> = 0.90–0.99, indicating that the size of the <em>α</em> relaxing entities should be between 2 and 8 nm. For <em>w</em><sub>TREG</sub> = 0.30–0.40, <em>T<sub>g</sub></em> also attains a constant value indicating that water also crystallizes in 2 nm pore samples when cooling them before the heating scans.</div></div>","PeriodicalId":16461,"journal":{"name":"Journal of Non-crystalline Solids","volume":"654 ","pages":"Article 123442"},"PeriodicalIF":3.2,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143421740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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