Pub Date : 2025-12-10DOI: 10.1016/j.actamat.2025.121823
Ramzi Nasser, Habib Elhouichet, Zhou Li, Ji-Ming Song
Engineering nanocomposites based on transition metal oxides (TMOs) shows an extensive interest due to their synergistic effects and strong interfacial interactions. In this report, a novel ZnFe2O4@ZnCo2O4 nanocomposite is bridged on Ni-Foam through one pot-hydrothermal way. The nanocomposite exhibits synergistic properties due to the build of a Mott-Schottky heterojunction, which enhances interfacial interactions, provides pathways for ion migration and diffusion, and enables rapid charge transfer, thereby improving energy storage dynamics. In full 3 electrode system, the ZnFe2O4@ZnCo2O4 electrode delivers extraordinary specific capacity of 913.7 C·g−1 (0.5 A·g−1), keeps marvellous capacitance retention of 79 % at 30 A·g−1, and a long cycle life with only 7 % capacity loss after 20,000 rounds. More encouragingly, an asymmetric supercapacitor device of ZnFe2O4@ZnCo2O4//active carbon (AC) delivers an impressive energy density of 73.77 Wh·kg−1 at 490 W·kg−1 power value. Two devices in series can successfully operate a white LED for several minutes. The foldability characteristic of the device shows good electrochemical properties even at various bending angles. Therefore, the new ZnFe2O4@ZnCo2O4 nanocomposite endorsed by Mott-Schottky junction, effectively addressed the charge states at the interface and ensured the specificity of electrode material, leading to superior electrochemical performance.
{"title":"Interfacial electron transfer in ZnFe2O4@ZnCo2O4 Mott-Schottky heterojunction boosting the electrochemical performance","authors":"Ramzi Nasser, Habib Elhouichet, Zhou Li, Ji-Ming Song","doi":"10.1016/j.actamat.2025.121823","DOIUrl":"https://doi.org/10.1016/j.actamat.2025.121823","url":null,"abstract":"Engineering nanocomposites based on transition metal oxides (TMOs) shows an extensive interest due to their synergistic effects and strong interfacial interactions. In this report, a novel ZnFe<sub>2</sub>O<sub>4</sub>@ZnCo<sub>2</sub>O<sub>4</sub> nanocomposite is bridged on Ni-Foam through one pot-hydrothermal way. The nanocomposite exhibits synergistic properties due to the build of a Mott-Schottky heterojunction, which enhances interfacial interactions, provides pathways for ion migration and diffusion, and enables rapid charge transfer, thereby improving energy storage dynamics. In full 3 electrode system, the ZnFe<sub>2</sub>O<sub>4</sub>@ZnCo<sub>2</sub>O<sub>4</sub> electrode delivers extraordinary specific capacity of 913.7 C·g<sup>−1</sup> (0.5 A·g<sup>−1</sup>), keeps marvellous capacitance retention of 79 % at 30 A·g<sup>−1</sup>, and a long cycle life with only 7 % capacity loss after 20,000 rounds. More encouragingly, an asymmetric supercapacitor device of ZnFe<sub>2</sub>O<sub>4</sub>@ZnCo<sub>2</sub>O<sub>4</sub>//active carbon (AC) delivers an impressive energy density of 73.77 Wh·kg<sup>−1</sup> at 490 W·kg<sup>−1</sup> power value. Two devices in series can successfully operate a white LED for several minutes. The foldability characteristic of the device shows good electrochemical properties even at various bending angles. Therefore, the new ZnFe<sub>2</sub>O<sub>4</sub>@ZnCo<sub>2</sub>O<sub>4</sub> nanocomposite endorsed by Mott-Schottky junction, effectively addressed the charge states at the interface and ensured the specificity of electrode material, leading to superior electrochemical performance.","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"13 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145717814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-12-09DOI: 10.1016/j.actamat.2025.121817
F.Z. Ding, P.C. Han, Y.H. Liu, K.X. Song, N.R. Tao, L. Lu
Although hetero-boundary strengthening is known to enhance material strength, its accurate quantification has remained a persistent challenge. In this study, we independently tailored the hetero-boundary density and established a direct quantitative relationship between hetero-boundary density and yield strength in heterostructured Cu. This approach enabled reliable quantification of the hetero-boundary strengthening, revealing a positive linear correlation between hetero-boundary density and yield strength with a slope of ∼2018 MPa·μm-1, representing the strengthening efficacy of hetero-boundaries. Further analysis shows that hetero-boundary strengthening could account for 40–56% of the total yield strength. Notably, when the domain/grain size is on the order of tens of micrometers, the strengthening effect from hetero-boundaries surpasses that of conventional grain boundaries by an order of magnitude. This work provides a quantitative framework for revealing hetero-boundary strengthening and highlights its dominant role in heterostructured materials.
{"title":"Revealing the hetero-boundary strengthening of heterostructured copper","authors":"F.Z. Ding, P.C. Han, Y.H. Liu, K.X. Song, N.R. Tao, L. Lu","doi":"10.1016/j.actamat.2025.121817","DOIUrl":"https://doi.org/10.1016/j.actamat.2025.121817","url":null,"abstract":"Although hetero-boundary strengthening is known to enhance material strength, its accurate quantification has remained a persistent challenge. In this study, we independently tailored the hetero-boundary density and established a direct quantitative relationship between hetero-boundary density and yield strength in heterostructured Cu. This approach enabled reliable quantification of the hetero-boundary strengthening, revealing a positive linear correlation between hetero-boundary density and yield strength with a slope of ∼2018 MPa·μm<sup>-1</sup>, representing the strengthening efficacy of hetero-boundaries. Further analysis shows that hetero-boundary strengthening could account for 40–56% of the total yield strength. Notably, when the domain/grain size is on the order of tens of micrometers, the strengthening effect from hetero-boundaries surpasses that of conventional grain boundaries by an order of magnitude. This work provides a quantitative framework for revealing hetero-boundary strengthening and highlights its dominant role in heterostructured materials.","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"26 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145711049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-12-09DOI: 10.1016/j.actamat.2025.121820
Guoliang Ren , Junwei Che , Hanchao Zhang , Huangyue Cai , Wenbo Li , Wei Hao , Qiaodan Hu , Xiaofeng Zhao , Fan Yang
Fluorite-type rare-earth tantalates with exceptional thermal insulation and oxygen barrier capabilities have emerged as promising candidates for next-generation thermal barrier coatings (TBCs), however, their low fracture toughness has raised significant concerns for such applications. To unveil the origin of the intrinsic brittleness so as to develop strategies for improving the fracture toughness, a multicomponent neuroevolution potential (NEP) with high accuracy and computational efficiency required for molecular dynamics simulations was developed, which enables, for the first time, multiscale analysis of fracture mechanisms in tantalate ceramics spanning from atomic to sub-nanometer scale. Multiscale molecular dynamics simulations using the NEP potential revealed that the intrinsic brittleness of Yb3TaO7 originated from the strong ionicity and high stiffness of the Ta-O bonds, based on which a bond-mediated toughening strategy was proposed. A series of tantalates were designed, among which Yb3Ta0.6Nb0.4O7 achieved a breakthrough 54.8 % toughness enhancement, which was confirmed by crack propagation simulations and indentation experiments. The developed NEP potential provides a transformative tool for complex oxide research, while the demonstrated engineering paradigm opens new avenues for developing damage-tolerant TBCs capable of operating beyond current temperature limits.
{"title":"Tailoring the fracture toughness of fluorite-type rare-earth tantalates: From atomic scale fracture mechanism to bond-mediated toughening design","authors":"Guoliang Ren , Junwei Che , Hanchao Zhang , Huangyue Cai , Wenbo Li , Wei Hao , Qiaodan Hu , Xiaofeng Zhao , Fan Yang","doi":"10.1016/j.actamat.2025.121820","DOIUrl":"10.1016/j.actamat.2025.121820","url":null,"abstract":"<div><div>Fluorite-type rare-earth tantalates with exceptional thermal insulation and oxygen barrier capabilities have emerged as promising candidates for next-generation thermal barrier coatings (TBCs), however, their low fracture toughness has raised significant concerns for such applications. To unveil the origin of the intrinsic brittleness so as to develop strategies for improving the fracture toughness, a multicomponent neuroevolution potential (NEP) with high accuracy and computational efficiency required for molecular dynamics simulations was developed, which enables, for the first time, multiscale analysis of fracture mechanisms in tantalate ceramics spanning from atomic to sub-nanometer scale. Multiscale molecular dynamics simulations using the NEP potential revealed that the intrinsic brittleness of Yb<sub>3</sub>TaO<sub>7</sub> originated from the strong ionicity and high stiffness of the Ta-O bonds, based on which a bond-mediated toughening strategy was proposed. A series of tantalates were designed, among which Yb<sub>3</sub>Ta<sub>0.6</sub>Nb<sub>0.4</sub>O<sub>7</sub> achieved a breakthrough 54.8 % toughness enhancement, which was confirmed by crack propagation simulations and indentation experiments. The developed NEP potential provides a transformative tool for complex oxide research, while the demonstrated engineering paradigm opens new avenues for developing damage-tolerant TBCs capable of operating beyond current temperature limits.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"304 ","pages":"Article 121820"},"PeriodicalIF":9.3,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145711112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-12-09DOI: 10.1016/j.actamat.2025.121818
Abdalrhaman Koko, Elsiddig Elmukashfi, Phani S. Karamched, T. James Marrow
High-resolution experimental methods now yield detailed elastic strain fields around cracks and other stress concentrators; however, these measurements alone cannot provide the displacement gradients required for a quantitative fracture assessment. Existing approaches to recover displacement fields from such data are either restricted to two dimensions, rely on strong assumptions about material behaviour, or lack robustness when confronted with noise typical of diffraction-based strain mapping. To address this limitation, we have developed a finite-element framework that reconstructs continuous displacement fields directly from measured deformation gradients without prescribing external loads or boundary conditions. The approach formulates strain integration as an over-determined least-squares problem defined on linear or quadratic elements in two and three dimensions. Validation using analytical 2D mode-I and 3D mixed-mode crack-tip fields demonstrates that the recovered displacements and derived stress intensity factors deviate from theoretical values by less than 4%. The method is further applied to HR-EBSD measurements around Vickers-indentation cracks in monocrystalline silicon, where the reconstructed fields reproduce AFM-measured surface topography and reveal distinct residual mixed-mode loading at neighbouring cracks. These results show that full-field diffraction-based strain measurements can be converted into mechanically meaningful displacement and fracture parameters with high fidelity. The method provides a practical route for quantifying crack driving forces in complex microstructures and can be extended to three-dimensional diffraction techniques and in situ studies of evolving damage.
{"title":"Computation of displacements from strain fields: Derivation, validation, and application","authors":"Abdalrhaman Koko, Elsiddig Elmukashfi, Phani S. Karamched, T. James Marrow","doi":"10.1016/j.actamat.2025.121818","DOIUrl":"https://doi.org/10.1016/j.actamat.2025.121818","url":null,"abstract":"High-resolution experimental methods now yield detailed elastic strain fields around cracks and other stress concentrators; however, these measurements alone cannot provide the displacement gradients required for a quantitative fracture assessment. Existing approaches to recover displacement fields from such data are either restricted to two dimensions, rely on strong assumptions about material behaviour, or lack robustness when confronted with noise typical of diffraction-based strain mapping. To address this limitation, we have developed a finite-element framework that reconstructs continuous displacement fields directly from measured deformation gradients without prescribing external loads or boundary conditions. The approach formulates strain integration as an over-determined least-squares problem defined on linear or quadratic elements in two and three dimensions. Validation using analytical 2D mode-I and 3D mixed-mode crack-tip fields demonstrates that the recovered displacements and derived stress intensity factors deviate from theoretical values by less than 4%. The method is further applied to HR-EBSD measurements around Vickers-indentation cracks in monocrystalline silicon, where the reconstructed fields reproduce AFM-measured surface topography and reveal distinct residual mixed-mode loading at neighbouring cracks. These results show that full-field diffraction-based strain measurements can be converted into mechanically meaningful displacement and fracture parameters with high fidelity. The method provides a practical route for quantifying crack driving forces in complex microstructures and can be extended to three-dimensional diffraction techniques and in situ studies of evolving damage.","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"60 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145711117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-12-06DOI: 10.1016/j.actamat.2025.121815
Guanfu Liu , Xiqi Chen , Bao Ou , Lixiang Lai , Yi Cheng , Ran Gao , Xiaoming Shi , Bin Li , He Qi , Yejing Dai
Dielectric energy storage ceramics with superior overall performance are essential for next-generation pulsed power devices. Attaining this objective necessitates surmounting the intrinsic trade-off between high polarization and elevated breakdown strength. Here, a novel core-shell heterostructures with dual functionality is strategically engineered by utilizing the substantial differences in sintering energies among various perovskite phases. The core, composed of wide-bandgap components, act as a dielectric breakdown reinforcement unit that effectively suppresses field-induced breakdown. Surrounding this, the shell region—rich in highly dynamic polar nanoregions—exhibits locally polymorphic polarization configurations that facilitate excellent polarization under high electric fields. This synergistic design enables precise control over both microstructure and local structure, resulting in optimized polarization behavior and enhanced dielectric breakdown strength. Consequently, an ultrahigh recoverable energy storage density (15.14 J cm-3) and a high energy efficiency (90.1 %) are achieved in relaxor ferroelectrics. This study presents a novel and facile strategy for the design of high-performance dielectric energy storage materials.
{"title":"Core-shell heterostructure with dual functionality for ultrahigh capacitive energy storage in lead-free relaxor ferroelectrics","authors":"Guanfu Liu , Xiqi Chen , Bao Ou , Lixiang Lai , Yi Cheng , Ran Gao , Xiaoming Shi , Bin Li , He Qi , Yejing Dai","doi":"10.1016/j.actamat.2025.121815","DOIUrl":"10.1016/j.actamat.2025.121815","url":null,"abstract":"<div><div>Dielectric energy storage ceramics with superior overall performance are essential for next-generation pulsed power devices. Attaining this objective necessitates surmounting the intrinsic trade-off between high polarization and elevated breakdown strength. Here, a novel core-shell heterostructures with dual functionality is strategically engineered by utilizing the substantial differences in sintering energies among various perovskite phases. The core, composed of wide-bandgap components, act as a dielectric breakdown reinforcement unit that effectively suppresses field-induced breakdown. Surrounding this, the shell region—rich in highly dynamic polar nanoregions—exhibits locally polymorphic polarization configurations that facilitate excellent polarization under high electric fields. This synergistic design enables precise control over both microstructure and local structure, resulting in optimized polarization behavior and enhanced dielectric breakdown strength. Consequently, an ultrahigh recoverable energy storage density (15.14 J cm<sup>-3</sup>) and a high energy efficiency (90.1 %) are achieved in relaxor ferroelectrics. This study presents a novel and facile strategy for the design of high-performance dielectric energy storage materials.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"304 ","pages":"Article 121815"},"PeriodicalIF":9.3,"publicationDate":"2025-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145689627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-12-06DOI: 10.1016/j.actamat.2025.121812
Pei Liu , Hao Zhang , Fan Yang , Zhizhi Wang , Aiqin Wang , Jingpei Xie , Yujie Yuan , Lai-Chang Zhang
β-Ti alloys have garnered significant interest in biomedical applications owing to their excellent mechanical properties and biocompatibility. However, simultaneously improving yield strength and ductility remains a persistent challenge, limiting their wider applications. Herein, we introduce just 0.3 wt.% interstitial oxygen atoms into a β-type Ti-35Nb-9Zr-7Sn alloy, inducing local chemical ordering (LCO) and face centered cubic (FCC) nanolayers at grain boundaries, which markedly enhance both yield strength and elongation in as-homogenized and as-rolled specimens. By converting planar dislocation slip into wavy slip, the intragranular LCO structure facilitates double cross-slip and dislocation multiplication, which collectively enhance strain-hardening behavior. Meanwhile, the interstitial oxygen-driven FCC phase nanolayers promote dislocation slip across grain boundaries, further improving ductility. This oxygen driven strategy overcomes the traditional strength-ductility trade off and offers a promising route for designing next generation load bearing biomedical β-Ti alloys.
{"title":"Simultaneous enhancement of strength and ductility of biomedical β-type Ti-35Nb-9Zr-7Sn alloy through oxygen-driven local chemical ordering and grain boundary nanolayers","authors":"Pei Liu , Hao Zhang , Fan Yang , Zhizhi Wang , Aiqin Wang , Jingpei Xie , Yujie Yuan , Lai-Chang Zhang","doi":"10.1016/j.actamat.2025.121812","DOIUrl":"10.1016/j.actamat.2025.121812","url":null,"abstract":"<div><div>β-Ti alloys have garnered significant interest in biomedical applications owing to their excellent mechanical properties and biocompatibility. However, simultaneously improving yield strength and ductility remains a persistent challenge, limiting their wider applications. Herein, we introduce just 0.3 wt.% interstitial oxygen atoms into a β-type Ti-35Nb-9Zr-7Sn alloy, inducing local chemical ordering (LCO) and face centered cubic (FCC) nanolayers at grain boundaries, which markedly enhance both yield strength and elongation in as-homogenized and as-rolled specimens. By converting planar dislocation slip into wavy slip, the intragranular LCO structure facilitates double cross-slip and dislocation multiplication, which collectively enhance strain-hardening behavior. Meanwhile, the interstitial oxygen-driven FCC phase nanolayers promote dislocation slip across grain boundaries, further improving ductility. This oxygen driven strategy overcomes the traditional strength-ductility trade off and offers a promising route for designing next generation load bearing biomedical β-Ti alloys.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"304 ","pages":"Article 121812"},"PeriodicalIF":9.3,"publicationDate":"2025-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145689628","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-12-06DOI: 10.1016/j.actamat.2025.121808
Biaobiao Yang , Mingdi Yu , Nafiseh Mollaei , Yidi Li , Miguel A. Monclús , Jingya Wang , Javier LLorca
The deformation mechanisms of pure Zinc (Zn) were studied through compression tests on single-crystal micropillars with various crystallographic orientations at both room temperature and 100 °C. When compressed along ∼ , the grains mainly deformed by 〈a〉 basal slip. The second easiest mode in pure Zn is 〈c + a〉 pyramidal slip. No compression twinning or 〈a〉 non-basal slip was observed, implying these mechanisms require much higher critical resolved shear stresses than 〈c + a〉 pyramidal slip. Interestingly, 〈c + a〉 dislocations were found to transition from the pyramidal plane to the basal plane. This transition was sensitive to both temperature and orientation, leading to diverse microstructures under different conditions. For example, numerous sessile 〈c + a〉 dislocations were observed on the basal plane after compression along the c-axis at room temperature. These dislocations contribute to dislocation accumulation beneath the micropillar, ultimately triggering recrystallization at the bottom of the micropillar. These findings provide critical insights into the temperature- and orientation-dependent deformation mechanisms in Zn and offer valuable guidance for the design of Zn-based alloys with enhanced mechanical properties.
{"title":"Deformation mechanisms of pure Zn studied by micropillar compression tests at room and elevated temperatures","authors":"Biaobiao Yang , Mingdi Yu , Nafiseh Mollaei , Yidi Li , Miguel A. Monclús , Jingya Wang , Javier LLorca","doi":"10.1016/j.actamat.2025.121808","DOIUrl":"10.1016/j.actamat.2025.121808","url":null,"abstract":"<div><div>The deformation mechanisms of pure Zinc (Zn) were studied through compression tests on single-crystal micropillars with various crystallographic orientations at both room temperature and 100 °C. When compressed along ∼ <span><math><mrow><mo>[</mo><mover><mrow><mn>1</mn></mrow><mo>‾</mo></mover><mn>2</mn><mover><mrow><mn>1</mn></mrow><mo>‾</mo></mover><mn>1</mn><mo>]</mo></mrow></math></span>, the grains mainly deformed by 〈<em>a</em>〉 basal slip. The second easiest mode in pure Zn is 〈<em>c</em> + <em>a</em>〉 pyramidal slip. No compression twinning or 〈<em>a</em>〉 non-basal slip was observed, implying these mechanisms require much higher critical resolved shear stresses than 〈<em>c</em> + <em>a</em>〉 pyramidal slip. Interestingly, 〈<em>c</em> + <em>a</em>〉 dislocations were found to transition from the pyramidal plane to the basal plane. This transition was sensitive to both temperature and orientation, leading to diverse microstructures under different conditions. For example, numerous sessile 〈<em>c</em> + <em>a</em>〉 dislocations were observed on the basal plane after compression along the <em>c</em>-axis at room temperature. These dislocations contribute to dislocation accumulation beneath the micropillar, ultimately triggering recrystallization at the bottom of the micropillar. These findings provide critical insights into the temperature- and orientation-dependent deformation mechanisms in Zn and offer valuable guidance for the design of Zn-based alloys with enhanced mechanical properties.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"304 ","pages":"Article 121808"},"PeriodicalIF":9.3,"publicationDate":"2025-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145689621","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the present study, operando and ex-situ experiments were conducted to evaluate the Ni migration behaviors in solid oxide fuel cell (SOFC) using patterned anodes. Cells with three different substrates, i.e. pure 8YSZ (Reference cell), 1 mol% Ni dissolved YSZ (Cell 1) and YSZ with a sintered thin Ni film (Cell 2) were tested. Both Cell 1 and Cell 2 exhibited accelerated migration compared to the Reference cell. However, only Cell 1 demonstrated enhanced interfacial stability. This is attributed to Ni dissolution, where Ni is strongly adhered to the substrate, thereby stabilizing the current fluctuation and mitigating performance degradation. Present findings elucidate the effect of Ni dissolution on stabilizing the Ni–YSZ interface and provide insights into the strategies for enhancing SOCs durability.
{"title":"Effect of Ni dissolution on Ni migration in solid oxide fuel cell patterned fuel electrode","authors":"Gao Yao, Yosuke Komatsu, Anna Sciazko, Katsuhiko Nishimura, Takao Okabe, Tooru Misawa, Zewei Lyu, Junyi Tao, Takaaki Shimura, Naoki Shikazono","doi":"10.1016/j.actamat.2025.121801","DOIUrl":"10.1016/j.actamat.2025.121801","url":null,"abstract":"<div><div>In the present study, <em>operando</em> and <em>ex-situ</em> experiments were conducted to evaluate the Ni migration behaviors in solid oxide fuel cell (SOFC) using patterned anodes. Cells with three different substrates, i.e. pure 8YSZ (Reference cell), 1 mol% Ni dissolved YSZ (Cell 1) and YSZ with a sintered thin Ni film (Cell 2) were tested. Both Cell 1 and Cell 2 exhibited accelerated migration compared to the Reference cell. However, only Cell 1 demonstrated enhanced interfacial stability. This is attributed to Ni dissolution, where Ni is strongly adhered to the substrate, thereby stabilizing the current fluctuation and mitigating performance degradation. Present findings elucidate the effect of Ni dissolution on stabilizing the Ni–YSZ interface and provide insights into the strategies for enhancing SOCs durability.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"304 ","pages":"Article 121801"},"PeriodicalIF":9.3,"publicationDate":"2025-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145689624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study elucidates the atomistic mechanisms governing the robust bonding between β-Si3N4 and Cu via a Ti-induced TiN interlayer employing an integrated experimental and computational approach. Density functional theory (DFT) calculations of the potential energy surfaces (PESs) of β-Si3N4 revealed a stronger chemical affinity of Ti compared with other metals. Following Ti deposition, the formation of TiN on β-Si3N4 was confirmed, and transmission electron microscopy (TEM) identified five distinct crystallographic orientation relationships (ORs) at the β-Si3N4/TiN interface. Lattice misfit analysis showed that all ORs exhibited minor mismatches, indicating a structurally adaptable interface. DFT-based adhesion energy calculations for representative ORs confirmed that these low-misfit configurations correspond to energetically stable interfaces exhibiting substantial work of adhesion. Electronic structure analyses revealed strong Ti–N bonds with both covalent and ionic character. These findings suggest that the system’s robustness stems from its inherent ability to form multiple, structurally coherent, and strongly bonded interfaces. Notably, thermal cycling tests confirmed the excellent interfacial reliability of the TiN-mediated Cu/β-Si3N4/Cu substrates, with a negligible delamination increase of less than 1% after 4500 cycles between –55 and 150 °C. This study provides direct atomistic insights into the Ti-mediated bonding mechanism and demonstrates the potential of the Cu–β-Si3N4 interface for high-reliability power electronics. Our integrated experimental–computational approach offers a framework for designing advanced metal–ceramic interfaces with optimized crystallographic alignment and adhesion properties.
{"title":"Experimental and first-principles insights into Ti-mediated Cu–Si3N4 interfaces for high-reliability electronic substrates","authors":"Hiroaki Tatsumi , Shunya Nitta , Atsushi M. Ito , Arimichi Takayama , Makoto Takahashi , Seongjae Moon , Eiki Tsushima , Hiroshi Nishikawa","doi":"10.1016/j.actamat.2025.121813","DOIUrl":"10.1016/j.actamat.2025.121813","url":null,"abstract":"<div><div>This study elucidates the atomistic mechanisms governing the robust bonding between β-Si<sub>3</sub>N<sub>4</sub> and Cu via a Ti-induced TiN interlayer employing an integrated experimental and computational approach. Density functional theory (DFT) calculations of the potential energy surfaces (PESs) of β-Si<sub>3</sub>N<sub>4</sub> revealed a stronger chemical affinity of Ti compared with other metals. Following Ti deposition, the formation of TiN on β-Si<sub>3</sub>N<sub>4</sub> was confirmed, and transmission electron microscopy (TEM) identified five distinct crystallographic orientation relationships (ORs) at the β-Si<sub>3</sub>N<sub>4</sub>/TiN interface. Lattice misfit analysis showed that all ORs exhibited minor mismatches, indicating a structurally adaptable interface. DFT-based adhesion energy calculations for representative ORs confirmed that these low-misfit configurations correspond to energetically stable interfaces exhibiting substantial work of adhesion. Electronic structure analyses revealed strong Ti–N bonds with both covalent and ionic character. These findings suggest that the system’s robustness stems from its inherent ability to form multiple, structurally coherent, and strongly bonded interfaces. Notably, thermal cycling tests confirmed the excellent interfacial reliability of the TiN-mediated Cu/β-Si<sub>3</sub>N<sub>4</sub>/Cu substrates, with a negligible delamination increase of less than 1% after 4500 cycles between –55 and 150 °C. This study provides direct atomistic insights into the Ti-mediated bonding mechanism and demonstrates the potential of the Cu–β-Si<sub>3</sub>N<sub>4</sub> interface for high-reliability power electronics. Our integrated experimental–computational approach offers a framework for designing advanced metal–ceramic interfaces with optimized crystallographic alignment and adhesion properties.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"304 ","pages":"Article 121813"},"PeriodicalIF":9.3,"publicationDate":"2025-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145697340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-12-05DOI: 10.1016/j.actamat.2025.121809
J. Choi, O. Muránsky, M.C. Messner, T. Wei, T. Hu, J.J. Kruzic, M.D. McMurtrey
Crystal plasticity finite element method (CPFEM) models are widely used to simulate the deformation behaviour of polycrystalline materials, but their calibration is often limited by their high computational cost and the non-convexity of the optimisation landscape. This study develops a multi-objective surrogate-assisted calibration workflow that couples a multi-objective genetic algorithm (MOGA) with an adaptively trained deep neural network (DNN) surrogate model to efficiently identify CPFEM parameters from experimental data. The workflow is demonstrated on three crystal plasticity (CP) formulations of increasing complexity — Voce hardening (VH), two-coefficient latent hardening (LH2), and six-coefficient latent hardening (LH6) — using in situ electron backscatter diffraction (EBSD) measurements of Alloy 617 under uniaxial tensile loading. The CPFEM models are calibrated against the experimentally observed stress–strain response and reorientation trajectories of eight grains, then validated against eight additional trajectories and overall texture evolution. Across the CP formulations, the macroscopic response was reproduced reliably, while differences emerged in robustness and the accuracy of grain-scale predictions. Repeated calibrations enabled direct analysis of variability in the identified material parameters. Including grain reorientation trajectories in the multi-objective calibration improved texture evolution predictions and filtered out physically inconsistent parameter sets that can arise from calibrating against only the stress–strain data. The workflow also demonstrates good transferability of calibrated parameters from a low- to a high-fidelity microstructural model. These results provide practical guidance for integrating in situ microstructural data into CPFEM through efficient, repeatable, and physically meaningful multi-objective calibration.
{"title":"Multi-Objective Surrogate-Assisted Calibration of CPFEM Models Using Macroscopic Response and In Situ EBSD Measurements of Grain Reorientation Trajectories","authors":"J. Choi, O. Muránsky, M.C. Messner, T. Wei, T. Hu, J.J. Kruzic, M.D. McMurtrey","doi":"10.1016/j.actamat.2025.121809","DOIUrl":"https://doi.org/10.1016/j.actamat.2025.121809","url":null,"abstract":"Crystal plasticity finite element method (CPFEM) models are widely used to simulate the deformation behaviour of polycrystalline materials, but their calibration is often limited by their high computational cost and the non-convexity of the optimisation landscape. This study develops a multi-objective surrogate-assisted calibration workflow that couples a multi-objective genetic algorithm (MOGA) with an adaptively trained deep neural network (DNN) surrogate model to efficiently identify CPFEM parameters from experimental data. The workflow is demonstrated on three crystal plasticity (CP) formulations of increasing complexity — Voce hardening (VH), two-coefficient latent hardening (LH2), and six-coefficient latent hardening (LH6) — using in situ electron backscatter diffraction (EBSD) measurements of Alloy 617 under uniaxial tensile loading. The CPFEM models are calibrated against the experimentally observed stress–strain response and reorientation trajectories of eight grains, then validated against eight additional trajectories and overall texture evolution. Across the CP formulations, the macroscopic response was reproduced reliably, while differences emerged in robustness and the accuracy of grain-scale predictions. Repeated calibrations enabled direct analysis of variability in the identified material parameters. Including grain reorientation trajectories in the multi-objective calibration improved texture evolution predictions and filtered out physically inconsistent parameter sets that can arise from calibrating against only the stress–strain data. The workflow also demonstrates good transferability of calibrated parameters from a low- to a high-fidelity microstructural model. These results provide practical guidance for integrating in situ microstructural data into CPFEM through efficient, repeatable, and physically meaningful multi-objective calibration.","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"10 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2025-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145689623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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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