Pub Date : 2024-11-22DOI: 10.1016/j.jallcom.2024.177697
Jun Han, Junhui Shao, Xingchen He, Najun Li, Shuxian Wang, Dongyun Chen, Jianmei Lu
Constructing heterojunctions has been proved to effectively improve the carrier transfer capability for enhanced catalytic activity. Herein, Ti3C2/BaTiO3 heterojunctions were fabricated through self-assembly driven by hydrogen bonding between piezoelectric barium titanate (BaTiO3) stabilized by oleic acid molecules and titanium carbide (Ti3C2) with surficial functional groups under continuous ultrasonic vibration. Owing to the formation of heterojunction, the separation of free charges can be promoted by the conductive Ti3C2. Additionally, the recombination of electrons and holes pairs in BaTiO3 can be hindered by built-in piezoelectric field. Hence, the piezocatalytic activity of Ti3C2/BaTiO3 was significantly enhanced by the accumulated piezoelectric effect, maintaining stability during the piezocatalytic degradation of bisphenol A and achieving rate constants that were 22.2 and 3.2 times higher than those of Ti3C2 and BaTiO3, respectively. This work thus presents a novel strategy for designing high-activity heterojunction piezocatalysts through hydrogen bonding self-assembly.
{"title":"Boosting piezocatalytic activity for hydrogen bonding self-assembled Ti3C2/BaTiO3 heterojunction via accumulated piezoelectric effect","authors":"Jun Han, Junhui Shao, Xingchen He, Najun Li, Shuxian Wang, Dongyun Chen, Jianmei Lu","doi":"10.1016/j.jallcom.2024.177697","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177697","url":null,"abstract":"Constructing heterojunctions has been proved to effectively improve the carrier transfer capability for enhanced catalytic activity. Herein, Ti<sub>3</sub>C<sub>2</sub>/BaTiO<sub>3</sub> heterojunctions were fabricated through self-assembly driven by hydrogen bonding between piezoelectric barium titanate (BaTiO<sub>3</sub>) stabilized by oleic acid molecules and titanium carbide (Ti<sub>3</sub>C<sub>2</sub>) with surficial functional groups under continuous ultrasonic vibration. Owing to the formation of heterojunction, the separation of free charges can be promoted by the conductive Ti<sub>3</sub>C<sub>2</sub>. Additionally, the recombination of electrons and holes pairs in BaTiO<sub>3</sub> can be hindered by built-in piezoelectric field. Hence, the piezocatalytic activity of Ti<sub>3</sub>C<sub>2</sub>/BaTiO<sub>3</sub> was significantly enhanced by the accumulated piezoelectric effect, maintaining stability during the piezocatalytic degradation of bisphenol A and achieving rate constants that were 22.2 and 3.2 times higher than those of Ti<sub>3</sub>C<sub>2</sub> and BaTiO<sub>3</sub>, respectively. This work thus presents a novel strategy for designing high-activity heterojunction piezocatalysts through hydrogen bonding self-assembly.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"188 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142684689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Al2TiO5 powder was prepared using the non-hydrolytic sol-gel route, with Al powder and titanium tetrachloride as precursor materials. The synthesized powder was characterized via XRD, DSC-TG, TEM, FTIR, FE-SEM, and laser particle size analyzer. The results indicated that Al2TiO5 powder can be synthesized at 750 ℃ via gelation when the aluminum-to-alcohol molar ratio was 1:14 and titanium tetrachloride concentration was 0.9 mol/L. The average particle size of Al2TiO5 powder was 80 nm using reflux gelation and 35 nm with direct drying gelation. The Al metal utilized the hydrogen chloride produced in situ to activate itself and formed Al-O-Ti hetero-bonds through non-hydrolytic polycondensation. The Al-O-Ti hetero-bonds underwent an exothermic reaction at around 695 ℃ to form Al2TiO5. This research has broadened the range of precursor materials available for preparing Al2TiO5 using the non-hydrolytic sol-gel route.
{"title":"Low-temperature preparation of nano-sized Al2TiO5 powder via non-hydrolytic sol-gel route with Al metal as the aluminum source","authors":"Quan Zhang, Junxiong Zhang, Yu Cao, Feng Jiang, Guo Feng, Jianmin Liu, Jian Liang, Hua Li, Qing Hu, Zhifang Xu","doi":"10.1016/j.jallcom.2024.177716","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177716","url":null,"abstract":"Al<sub>2</sub>TiO<sub>5</sub> powder was prepared using the non-hydrolytic sol-gel route, with Al powder and titanium tetrachloride as precursor materials. The synthesized powder was characterized via XRD, DSC-TG, TEM, FTIR, FE-SEM, and laser particle size analyzer. The results indicated that Al<sub>2</sub>TiO<sub>5</sub> powder can be synthesized at 750 ℃ via gelation when the aluminum-to-alcohol molar ratio was 1:14 and titanium tetrachloride concentration was 0.9<!-- --> <!-- -->mol/L. The average particle size of Al<sub>2</sub>TiO<sub>5</sub> powder was 80<!-- --> <!-- -->nm using reflux gelation and 35<!-- --> <!-- -->nm with direct drying gelation. The Al metal utilized the hydrogen chloride produced in situ to activate itself and formed Al-O-Ti hetero-bonds through non-hydrolytic polycondensation. The Al-O-Ti hetero-bonds underwent an exothermic reaction at around 695 ℃ to form Al<sub>2</sub>TiO<sub>5</sub>. This research has broadened the range of precursor materials available for preparing Al<sub>2</sub>TiO<sub>5</sub> using the non-hydrolytic sol-gel route.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"110 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142684684","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-11-22DOI: 10.1016/j.jallcom.2024.177723
A.R. Dilipan, H. Sepehri-Amin, R. Modak, V.K. Kushwaha, Y. Sakuraba, K. Uchida, K. Hono, Y.K. Takahashi
We investigated the effect of composition on the phase and extrinsic magnetic properties of TbCu7-type SmFe-based compounds using combinatorial sputtering technique. Composition-spread thin films of SmFex (x=6.4 to 12.7) and SmFexN (x=6.8 to 12.8) were synthesized using a linear shutter-assisted combinatorial sputtering technique. A high-throughput composition, phase, and magnetic characterization were performed on 18 different locations along the film using X-ray diffraction (XRD), X-ray fluorescence (XRF), and magneto-optical Kerr effect (MOKE) magnetometry. The optimal composition with the highest fraction of the main phase was found to be in SmFe9.8 and SmFe9.5N and beyond this composition, the α-Fe secondary ferromagnetic phase emerges. The coercive field and remanence of the SmFe9.5N is estimated to be ~0.8 T and ~1.2 T respectively. Further, scanning transmission electron microscopy (STEM) was performed at SmFe9.5N to correlate the microstructure with their extrinsic magnetic properties. Overall, this study demonstrates the impact of composition variation on the phase and extrinsic magnetic properties of TbCu7-type SmFe-based compounds, which can be utilized to tailor magnetic properties for targeted advanced magnet applications.
{"title":"Combinatorial sputtering synthesis of TbCu7-type Sm-Fe based compounds: a study on phase, composition, and extrinsic magnetic properties.","authors":"A.R. Dilipan, H. Sepehri-Amin, R. Modak, V.K. Kushwaha, Y. Sakuraba, K. Uchida, K. Hono, Y.K. Takahashi","doi":"10.1016/j.jallcom.2024.177723","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177723","url":null,"abstract":"We investigated the effect of composition on the phase and extrinsic magnetic properties of TbCu<sub>7</sub>-type SmFe-based compounds using combinatorial sputtering technique. Composition-spread thin films of SmFe<sub><em>x</em></sub> (<em>x</em>=6.4 to 12.7) and SmFe<sub><em>x</em></sub>N (<em>x</em>=6.8 to 12.8) were synthesized using a linear shutter-assisted combinatorial sputtering technique. A high-throughput composition, phase, and magnetic characterization were performed on 18 different locations along the film using X-ray diffraction (XRD), X-ray fluorescence (XRF), and magneto-optical Kerr effect (MOKE) magnetometry. The optimal composition with the highest fraction of the main phase was found to be in SmFe<sub>9.8</sub> and SmFe<sub>9.5</sub>N and beyond this composition, the <em>α</em>-Fe secondary ferromagnetic phase emerges. The coercive field and remanence of the SmFe<sub>9.5</sub>N is estimated to be ~0.8<!-- --> <!-- -->T and ~1.2<!-- --> <!-- -->T respectively. Further, scanning transmission electron microscopy (STEM) was performed at SmFe<sub>9.5</sub>N to correlate the microstructure with their extrinsic magnetic properties. Overall, this study demonstrates the impact of composition variation on the phase and extrinsic magnetic properties of TbCu<sub>7</sub>-type SmFe-based compounds, which can be utilized to tailor magnetic properties for targeted advanced magnet applications.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"37 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142691039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-11-21DOI: 10.1016/j.jallcom.2024.177701
Amira. H. Abdelhamid, Asmaa. M.A. Omar, Nadia. H. Yahia, M.M. El-Rabiei, Sameh S. Ali, Gomaa Khabiri, Hemdan S.H. Mohamed
Herein, well-constructed 2D active (110) and (111) faceted Cu2O nanosheets are in-situ grown on the surface of spindle MIL-88A to form a novel porous MIL88A (Fe)@active faceted Cu2O core-shell heterostructure via a facile solvothermal method. The fabricated heterostructure is optimized to be a promising catalyst for the catalytic reduction of various nitrophenol compounds such as P-nitrophenol and 2,4-dinitrophenols, as well as the removal of methylene blue dye (MB). The optimal M88@Cu2O-2 heterostructure demonstrated an outstanding catalytic performance for reducing nitrophenols, reaching 96.7% for P-nitrophenol and 96.1% for 2.4-dinitrophenol. It also achieved excellent photocatalytic activity for MB dye, reaching 95% through 30 min, compared to 64% and 72% for Cu2O and MIL-88A, with rate constants (k) reaching 0.1, 0.038, and 0.04 min-1, respectively. The surprising photocatalytic performance of the prepared structure could be attributed to the following aspects: (i) the growth of the active (111) and (110) facets Cu2O on the surface of MIL-88A, which could provide various surface energies, reactivates, and crystallographic arrangements, all of which impact the photocatalytic efficiency of the designed M88@Cu2O-2 heterostructure, (ii) the construction of an efficient heterojunction between active faceted Cu2O and MIL88A, which resists the recombination of e- and h+, improving the migration and separation of charge carriers, and (iii) the core-shell construction could provide more electron transport channels to significantly enhance the suppression of electron-hole pair recombination in the photocatalytic process. Besides that, the M88@Cu2O-2 core-shell has great photo-electrochemical performance, reaching 17.68 μA/cm2 for the photocurrent test and 73 mA/cm2 for the LSV test when exposed to visible light. Our study will provide a new vision for developing more hierarchical core/shell MOF-based heterostructures with outstanding multifunctional performance for future industrial practice.
{"title":"In-Situ Growing of MIL88A(Fe)@Active Faceted Cu2O Core-Shell Heterostructure for Super Photocatalytic Performance and Catalytic Reduction of Toxic Nitrophenol Compounds","authors":"Amira. H. Abdelhamid, Asmaa. M.A. Omar, Nadia. H. Yahia, M.M. El-Rabiei, Sameh S. Ali, Gomaa Khabiri, Hemdan S.H. Mohamed","doi":"10.1016/j.jallcom.2024.177701","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177701","url":null,"abstract":"Herein, well-constructed 2D active (110) and (111) faceted Cu<sub>2</sub>O nanosheets are in-situ grown on the surface of spindle MIL-88A to form a novel porous MIL88A (Fe)@active faceted Cu<sub>2</sub>O core-shell heterostructure via a facile solvothermal method. The fabricated heterostructure is optimized to be a promising catalyst for the catalytic reduction of various nitrophenol compounds such as P-nitrophenol and 2,4-dinitrophenols, as well as the removal of methylene blue dye (MB). The optimal M88@Cu<sub>2</sub>O-2 heterostructure demonstrated an outstanding catalytic performance for reducing nitrophenols, reaching 96.7% for P-nitrophenol and 96.1% for 2.4-dinitrophenol. It also achieved excellent photocatalytic activity for MB dye, reaching 95% through 30<!-- --> <!-- -->min, compared to 64% and 72% for Cu<sub>2</sub>O and MIL-88A, with rate constants (k) reaching 0.1, 0.038, and 0.04<!-- --> <!-- -->min<sup>-1</sup>, respectively. The surprising photocatalytic performance of the prepared structure could be attributed to the following aspects: (i) the growth of the active (111) and (110) facets Cu<sub>2</sub>O on the surface of MIL-88A, which could provide various surface energies, reactivates, and crystallographic arrangements, all of which impact the photocatalytic efficiency of the designed M88@Cu<sub>2</sub>O-2 heterostructure, (ii) the construction of an efficient heterojunction between active faceted Cu<sub>2</sub>O and MIL88A, which resists the recombination of e<sup>-</sup> and h<sup>+</sup>, improving the migration and separation of charge carriers, and (iii) the core-shell construction could provide more electron transport channels to significantly enhance the suppression of electron-hole pair recombination in the photocatalytic process. Besides that, the M88@Cu<sub>2</sub>O-2 core-shell has great photo-electrochemical performance, reaching 17.68 μA/cm<sup>2</sup> for the photocurrent test and 73<!-- --> <!-- -->mA/cm<sup>2</sup> for the LSV test when exposed to visible light. Our study will provide a new vision for developing more hierarchical core/shell MOF-based heterostructures with outstanding multifunctional performance for future industrial practice.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"129 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142678178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-11-21DOI: 10.1016/j.jallcom.2024.177699
Jie Gao, Dong Zhong, Dan Zheng, Muhammad Akbar, Kun Chen, Cong Jiang, Yuanjing Meng, Baoyuan Wang
Sluggish ionic conductivity of electrolyte material at low operational temperature creates challenges in the commercialization of low-temperature solid oxide fuel cells (LT-SOFCs). It is imperative to develop promising electrolyte along with excellent ionic conductivity to realize the decent output power at low temperature. The present study proposes a wide band gap semiconductor samarium doped lanthanum oxide (SLO), and its electrolyte functionality was evaluated in LT-SOFCs. The SOFC based on SLO electrolyte achieved promising performance of 977 mW cm-2 along with high open circuit voltage of 1.02 V at 550 ℃. Sm doping in lanthanum significantly decrease the grain boundary resistance in the SLO electrolyte. Conductivity tests show that SLO possess both proton and oxygen ion conductivities, and which are significantly improved after Sm doping. Furthermore, on performing durability test the cell persistently get stable for 20 hours. This work demonstrates the potential of SLO as a high-performance electrolyte for LT-SOFCs.
电解质材料在低工作温度下的离子导电性较弱，这给低温固体氧化物燃料电池（LT-SOFC）的商业化带来了挑战。当务之急是开发出具有良好离子传导性的电解质，以便在低温条件下实现良好的输出功率。本研究提出了一种宽带隙半导体掺钐氧化镧（SLO），并对其在低温固体氧化物燃料电池中的电解质功能进行了评估。基于 SLO 电解质的 SOFC 在 550 ℃ 时实现了 977 mW cm-2 的良好性能和 1.02 V 的高开路电压。在 SLO 电解质中，镧中的 Sm 掺杂大大降低了晶界电阻。电导率测试表明，SLO 具有质子和氧离子电导率，掺入 Sm 后电导率明显提高。此外，在进行耐久性测试时，电池可在 20 小时内保持稳定。这项工作证明了 SLO 作为 LT-SOFC 的高性能电解质的潜力。
{"title":"Excellent electrolyte functionality of Sm-doped La2O3 wide band gap semiconductor for low temperature solid oxide fuel cells","authors":"Jie Gao, Dong Zhong, Dan Zheng, Muhammad Akbar, Kun Chen, Cong Jiang, Yuanjing Meng, Baoyuan Wang","doi":"10.1016/j.jallcom.2024.177699","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177699","url":null,"abstract":"Sluggish ionic conductivity of electrolyte material at low operational temperature creates challenges in the commercialization of low-temperature solid oxide fuel cells (LT-SOFCs). It is imperative to develop promising electrolyte along with excellent ionic conductivity to realize the decent output power at low temperature. The present study proposes a wide band gap semiconductor samarium doped lanthanum oxide (SLO), and its electrolyte functionality was evaluated in LT-SOFCs. The SOFC based on SLO electrolyte achieved promising performance of 977<!-- --> <!-- -->mW<!-- --> <!-- -->cm<sup>-2</sup> along with high open circuit voltage of 1.02<!-- --> <!-- -->V at 550 ℃. Sm doping in lanthanum significantly decrease the grain boundary resistance in the SLO electrolyte. Conductivity tests show that SLO possess both proton and oxygen ion conductivities, and which are significantly improved after Sm doping. Furthermore, on performing durability test the cell persistently get stable for 20<!-- --> <!-- -->hours. This work demonstrates the potential of SLO as a high-performance electrolyte for LT-SOFCs.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"23 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142678948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Combining the intrinsic (crack tip plasticity) and extrinsic (crack deflection) toughening mechanism, the anisotropy of fracture toughness for Ti-22Al-25Nb alloy obtain by B2 phase region isothermal forging process is discussed. The results show that the sequence of fracture toughness from high to low is RD (radial direction), OD (45° to RD) and AD (axial direction). Intrinsically, it is found that the damage of lamellar O phase ahead of the crack tip dominates crack propagation. Compared with grain interior, continuous lamellar O phase on grain boundary can more easily promote the nucleation and propagation of crack, reducing the intrinsic resistance of crack propagation. Consequently, AD sample with intergranular fracture has the smallest crack tip plastic zone than RD and OD samples with transgranular fracture. Due to the activation of prism <a> slip for O phase, the texture of RD sample has a higher Schmid factor than that of OD sample, resulting in better crack tip plasticity. Extrinsically, it can be concluded that grain boundaries have a significant effect on crack deflection due to the pancake shaped B2 morphology. For RD sample, the grain boundary is perpendicular to the initial crack plane, so the stress intensity factor (KI) required for cleavage fracture is less than that for intergranular fracture. The deflection of the cleavage facets results in the highest crack propagation tortuosity. Also, the crack propagation near grain boundary of OD sample leads to significant deflection because the grain boundary is located in the direction of maximum shear stress. Compared with RD and OD samples, the KI required for intergranular fracture of AD sample is minimum, results in a flat fracture path.
结合内在（裂纹尖端塑性）和外在（裂纹偏转）增韧机制，讨论了通过 B2 相区等温锻造工艺获得的 Ti-22Al-25Nb 合金断裂韧性的各向异性。结果表明，断裂韧性从高到低的顺序为 RD（径向）、OD（与 RD 成 45°）和 AD（轴向）。从本质上看，裂纹尖端前方片状 O 相的破坏主导了裂纹的扩展。与晶粒内部相比，晶界上的连续片状 O 相更容易促进裂纹的成核和扩展，从而降低了裂纹扩展的内在阻力。因此，与晶间断裂的 RD 和 OD 样品相比，晶间断裂的 AD 样品的裂纹尖端塑性区最小。由于激活了 O 相的棱柱滑移，RD 样品的纹理比 OD 样品的纹理具有更高的施密特因子，因此裂纹尖端塑性更好。从外部来看，由于 B2 形状呈薄饼状，因此可以断定晶界对裂纹偏转有显著影响。对于 RD 样品，晶界垂直于初始裂纹平面，因此劈裂断裂所需的应力强度因子（KI）小于晶间断裂。劈裂面的偏转会导致最高的裂纹扩展迂回度。此外，由于晶界位于最大剪应力方向，OD 样品晶界附近的裂纹扩展也会导致显著偏转。与 RD 和 OD 样品相比，AD 样品晶间断裂所需的 KI 最小，因此断裂路径平坦。
{"title":"Anisotropy in fracture toughness and toughening mechanism of Ti-22Al-25Nb alloy related to texture and grain boundary damage","authors":"Penghui Zhang, Weidong Zeng, Fan Zhang, Haoyuan Ma, Jianwei Xu, Xiaobo Liang, Yongqing Zhao","doi":"10.1016/j.jallcom.2024.177703","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177703","url":null,"abstract":"Combining the intrinsic (crack tip plasticity) and extrinsic (crack deflection) toughening mechanism, the anisotropy of fracture toughness for Ti-22Al-25Nb alloy obtain by B2 phase region isothermal forging process is discussed. The results show that the sequence of fracture toughness from high to low is RD (radial direction), OD (45° to RD) and AD (axial direction). Intrinsically, it is found that the damage of lamellar O phase ahead of the crack tip dominates crack propagation. Compared with grain interior, continuous lamellar O phase on grain boundary can more easily promote the nucleation and propagation of crack, reducing the intrinsic resistance of crack propagation. Consequently, AD sample with intergranular fracture has the smallest crack tip plastic zone than RD and OD samples with transgranular fracture. Due to the activation of prism <a> slip for O phase, the texture of RD sample has a higher Schmid factor than that of OD sample, resulting in better crack tip plasticity. Extrinsically, it can be concluded that grain boundaries have a significant effect on crack deflection due to the pancake shaped B2 morphology. For RD sample, the grain boundary is perpendicular to the initial crack plane, so the stress intensity factor (<em>K</em><sub><em>I</em></sub>) required for cleavage fracture is less than that for intergranular fracture. The deflection of the cleavage facets results in the highest crack propagation tortuosity. Also, the crack propagation near grain boundary of OD sample leads to significant deflection because the grain boundary is located in the direction of maximum shear stress. Compared with RD and OD samples, the <em>K</em><sub><em>I</em></sub> required for intergranular fracture of AD sample is minimum, results in a flat fracture path.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"1 6 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142678175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The mechanism of microcrack initiation for notch high cycle fatigue (NHCF) in Ti-55531 alloy with various multilevel lamellar microstructures (MLMs) under the certain notch root radius (R=0.34 mm) was thoroughly investigated. Results indicate that the primary microstructure unit controlling fatigue crack initiation is the secondary α (αs) lamellae. Majority of microvoids and microcracks initiate at the interfaces between αs and residual β matrix (βr) nearby the notch root, propagating towards the specimen core along αs/βr interfaces or passing through αs lamellae, forming longer microcracks. Moreover, as the width/length ratio of αs lamella and α colony (dα and dc) increases, the cyclic plastic deformation of αs lamella and α colony intensify significantly. Consequently, numerous fractures occurred in αs lamellae, greatly facilitating fatigue microcracks initiation and leading to a severe reduction in both fatigue life and strength of the Ti-55531 alloy. Besides slipping and twinning, a small number of stacking faults (SFs) were also detected in the αs lamellae at smaller microstrutural size (dα=0.049 and 0.053, dc=0.148 and 0.168). Interestingly, the interaction between twins, basal SFs, and dislocation slip could be another significant mechanism that promotes the cracking of αs/βr interfaces for NHCF microcrack initiation in this alloy. Furthermore, with an increasing of dα and dc, the occurrence of slipping increases, while the occurrences of twins and SFs decrease.
{"title":"Influence of multilevel lamellar microstructure on notch high cycle fatigue properties and crack initiation behavior of Ti-55531 alloy","authors":"Yanyan Zhao, Zhong Zhang, Chaowen Huang, Jiang Yang, Changsheng Tan, Mingpan Wan, Yongqing Zhao","doi":"10.1016/j.jallcom.2024.177684","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177684","url":null,"abstract":"The mechanism of microcrack initiation for notch high cycle fatigue (NHCF) in Ti-55531 alloy with various multilevel lamellar microstructures (MLMs) under the certain notch root radius (<em>R</em>=0.34<!-- --> <!-- -->mm) was thoroughly investigated. Results indicate that the primary microstructure unit controlling fatigue crack initiation is the secondary α (α<sub>s</sub>) lamellae. Majority of microvoids and microcracks initiate at the interfaces between α<sub>s</sub> and residual β matrix (β<sub>r</sub>) nearby the notch root, propagating towards the specimen core along α<sub>s</sub>/β<sub>r</sub> interfaces or passing through α<sub>s</sub> lamellae, forming longer microcracks. Moreover, as the width/length ratio of α<sub>s</sub> lamella and α colony (<em>d</em><sub><em>α</em></sub> and <em>d</em><sub><em>c</em></sub>) increases, the cyclic plastic deformation of α<sub>s</sub> lamella and α colony intensify significantly. Consequently, numerous fractures occurred in α<sub>s</sub> lamellae, greatly facilitating fatigue microcracks initiation and leading to a severe reduction in both fatigue life and strength of the Ti-55531 alloy. Besides slipping and twinning, a small number of stacking faults (SFs) were also detected in the α<sub>s</sub> lamellae at smaller microstrutural size (<em>d</em><sub><em>α</em></sub>=0.049 and 0.053, <em>d</em><sub><em>c</em></sub>=0.148 and 0.168). Interestingly, the interaction between twins, basal SFs, and dislocation slip could be another significant mechanism that promotes the cracking of α<sub>s</sub>/β<sub>r</sub> interfaces for NHCF microcrack initiation in this alloy. Furthermore, with an increasing of <em>d</em><sub><em>α</em></sub> and <em>d</em><sub><em>c</em></sub>, the occurrence of slipping increases, while the occurrences of twins and SFs decrease.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"13 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142678180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-11-21DOI: 10.1016/j.jallcom.2024.177694
Song Yang, Shujie Jiao, Yiyin Nie, Yue Zhao, Xiaodi Jia, Shiyong Gao, Dongbo Wang, Jinzhong Wang, Hongwei Liang
Topological insulator bismuth telluride (Bi2Te3), an exotic state of quantum matter, has broad application prospects in next-generation optoelectronic devices. However, photoexcited carriers in Bi2Te3 usually relax rapidly due to the lack of a large band gap. Herein, high-quality Bi2Te3/Si heterojunction is successfully synthesized by a low-cost modified two-step solvothermal method to grow large-scale free-standing Bi2Te3 nanosheets on a Si substrate. Benefiting from the promotion of photogenerated carrier separation and transport by the built-in electric field at the Bi2Te3/Si heterojunction interface, the Bi2Te3/Si heterojunction photodetector exhibits a high responsivity of 16.44 mA W-1, a high specific detectivity of 2.44 × 1011 Jones, and fast rise/recovery times of 11/13 ms under 470 nm illumination at zero bias. Additionally, the device has potential applications in high-resolution imaging. In view of its overall photosensitivity performance and low cost, the Bi2Te3/Si heterojunction synthesized by the solvothermal method has a promising application in fast broadband photodetectors, and also provide a new route for the growth of Bi2Te3 nanosheets on substrates.
拓扑绝缘体碲化铋（Bi2Te3）是一种奇异的量子态物质，在下一代光电器件中具有广阔的应用前景。然而，由于缺乏较大的带隙，Bi2Te3 中的光激发载流子通常会迅速弛豫。本文采用一种低成本的改良两步溶热法，在硅衬底上生长出大规模独立的 Bi2Te3 纳米片，成功合成了高质量的 Bi2Te3/Si 异质结。得益于 Bi2Te3/Si 异质结界面上的内置电场对光生载流子分离和传输的促进作用，Bi2Te3/Si 异质结光电探测器在零偏压下的 470 纳米光照条件下表现出 16.44 mA W-1 的高响应率、2.44 × 1011 Jones 的高比检测率和 11/13 ms 的快速上升/恢复时间。此外，该器件还有可能应用于高分辨率成像。鉴于其整体光敏性能和低成本，溶热法合成的 Bi2Te3/Si 异质结在快速宽带光探测器中具有广阔的应用前景，同时也为在衬底上生长 Bi2Te3 纳米片提供了一条新途径。
{"title":"Large-scale free-standing Bi2Te3/Si heterostructures developed by a modified solvothermal method for a self-powered and efficient imaging photodetector","authors":"Song Yang, Shujie Jiao, Yiyin Nie, Yue Zhao, Xiaodi Jia, Shiyong Gao, Dongbo Wang, Jinzhong Wang, Hongwei Liang","doi":"10.1016/j.jallcom.2024.177694","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177694","url":null,"abstract":"Topological insulator bismuth telluride (Bi<sub>2</sub>Te<sub>3</sub>), an exotic state of quantum matter, has broad application prospects in next-generation optoelectronic devices. However, photoexcited carriers in Bi<sub>2</sub>Te<sub>3</sub> usually relax rapidly due to the lack of a large band gap. Herein, high-quality Bi<sub>2</sub>Te<sub>3</sub>/Si heterojunction is successfully synthesized by a low-cost modified two-step solvothermal method to grow large-scale free-standing Bi<sub>2</sub>Te<sub>3</sub> nanosheets on a Si substrate. Benefiting from the promotion of photogenerated carrier separation and transport by the built-in electric field at the Bi<sub>2</sub>Te<sub>3</sub>/Si heterojunction interface, the Bi<sub>2</sub>Te<sub>3</sub>/Si heterojunction photodetector exhibits a high responsivity of 16.44<!-- --> <!-- -->mA<!-- --> <!-- -->W<sup>-1</sup>, a high specific detectivity of 2.44 × 10<sup>11</sup> Jones, and fast rise/recovery times of 11/13 ms under 470<!-- --> <!-- -->nm illumination at zero bias. Additionally, the device has potential applications in high-resolution imaging. In view of its overall photosensitivity performance and low cost, the Bi<sub>2</sub>Te<sub>3</sub>/Si heterojunction synthesized by the solvothermal method has a promising application in fast broadband photodetectors, and also provide a new route for the growth of Bi<sub>2</sub>Te<sub>3</sub> nanosheets on substrates.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"6 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142678181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The strength-ductility trade-off presents a significant challenge in the development of magnesium matrix composites (MMCs). A novel strategy that combines powder pre-dispersion, nano-SiC/Al master alloy sintering, stir casting, and hot extrusion combined method was introduced to prepare the strength-ductility synergetic SiC/ZK60 composites. The microstructural evolution and mechanical properties of these composites have been thoroughly investigated and compared. The results demonstrate that SiC particles are uniformly distributed within the as-solution-treated composites, and extrusion processes promote cluster refinement. Microstructural characterization shows that adding nano-SiC/Al enhances grain refinement and facilitates the precipitation of secondary phases. The grain refinement is attributed to the accelerated dynamic recrystallization (DRX) and nano-particle pinning, where particle stimulated nucleation (PSN), continue DRX (CDRX), and discontinue DRX (DDRX) are the dominant DRX mechanisms of composites. This process is further enhanced by increased nucleation sites induced by SiC, which facilitate the precipitation of MgZn2 and Zr phases. Additionally, a microscale Al3Zr phase precipitates within the composites due to aluminum addition. Notably, both strength and ductility, as well as elastic modulus (E) of 10SiC/ZK60 and 20SiC/ZK60 composites were improved simultaneously, with optimal ultimate tensile strength and elongation (EL) increasing by nearly 10%. Grain refinement emerges as a primary factor contributing to enhanced mechanical properties. Also, load transfer and stress release caused by multiple crack sources contribute significantly to strength and ductility strengthening, respectively.
{"title":"Microstructure and mechanical properties of strength-ductility synergetic SiC/ZK60 composites by a pre-dispersion strategy","authors":"Yinghao Feng, Chaoyang Sun, Sinuo Xu, Jingchen Liu, Lingyun Qian","doi":"10.1016/j.jallcom.2024.177702","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177702","url":null,"abstract":"The strength-ductility trade-off presents a significant challenge in the development of magnesium matrix composites (MMCs). A novel strategy that combines powder pre-dispersion, nano-SiC/Al master alloy sintering, stir casting, and hot extrusion combined method was introduced to prepare the strength-ductility synergetic SiC/ZK60 composites. The microstructural evolution and mechanical properties of these composites have been thoroughly investigated and compared. The results demonstrate that SiC particles are uniformly distributed within the as-solution-treated composites, and extrusion processes promote cluster refinement. Microstructural characterization shows that adding nano-SiC/Al enhances grain refinement and facilitates the precipitation of secondary phases. The grain refinement is attributed to the accelerated dynamic recrystallization (DRX) and nano-particle pinning, where particle stimulated nucleation (PSN), continue DRX (CDRX), and discontinue DRX (DDRX) are the dominant DRX mechanisms of composites. This process is further enhanced by increased nucleation sites induced by SiC, which facilitate the precipitation of MgZn<sub>2</sub> and Zr phases. Additionally, a microscale Al<sub>3</sub>Zr phase precipitates within the composites due to aluminum addition. Notably, both strength and ductility, as well as elastic modulus (E) of 10SiC/ZK60 and 20SiC/ZK60 composites were improved simultaneously, with optimal ultimate tensile strength and elongation (EL) increasing by nearly 10%. Grain refinement emerges as a primary factor contributing to enhanced mechanical properties. Also, load transfer and stress release caused by multiple crack sources contribute significantly to strength and ductility strengthening, respectively.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"108 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142678174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-11-21DOI: 10.1016/j.jallcom.2024.177515
Siddhi Garg, Ashok K. Verma, H.K. Poswal, T.C.N. Nicacio, D. Errandonea, Nandini Garg
In this study, the wolframite phase of ZnMoO4 was investigated under compression using x-ray diffraction (XRD), Raman spectroscopy and ab-initio calculations. The enthalpy calculations show that β-ZnMoO4 is a metastable phase at ambient pressure and becomes the most stable phase above 2 GPa. New diffraction peaks were observed in XRD patterns ~ 40 GPa, which indicate that it has undergone a phase transition to a lower symmetry phase. These diffraction peaks could be assigned to the (1 1 0), (2 0 -2), (2 2 0) peak of the base-centered monoclinic phase, Cm, determined by ab-initio crystal structure search. We observed a co-existence of the ambient and high pressure phases in the XRD data above 40 GPa, which clearly indicates the first order nature of the phase transition. The Raman spectroscopic studies showed an abrupt change in intensities and red shift of the highest intensity peak ~ 39 GPa, thus corroborating the x-ray diffraction and ab-initio results. This shift is correlated with a coordination increase from 6 to 9 in Mo+6 ions associated with this phase transition to Cm phase. This study also shows that β-ZnMoO4 is an insulator with a direct band gap of 2.9 eV at ambient pressure as determined from UV visible absorption spectroscopy making it an ideal material for photocatalytic applications. Our electronic calculations corroborate this finding.
{"title":"High Pressure Investigation of Structural and Electronic Behavior of β-ZnMoO4","authors":"Siddhi Garg, Ashok K. Verma, H.K. Poswal, T.C.N. Nicacio, D. Errandonea, Nandini Garg","doi":"10.1016/j.jallcom.2024.177515","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177515","url":null,"abstract":"In this study, the wolframite phase of ZnMoO<sub>4</sub> was investigated under compression using x-ray diffraction (XRD), Raman spectroscopy and <em>ab-initio</em> calculations. The enthalpy calculations show that β-ZnMoO<sub>4</sub> is a metastable phase at ambient pressure and becomes the most stable phase above 2<!-- --> <!-- -->GPa. New diffraction peaks were observed in XRD patterns ~ 40<!-- --> <!-- -->GPa, which indicate that it has undergone a phase transition to a lower symmetry phase. These diffraction peaks could be assigned to the (1 1 0), (2 0 -2), (2 2 0) peak of the base-centered monoclinic phase, <em>Cm</em>, determined by <em>ab-initio</em> crystal structure search. We observed a co-existence of the ambient and high pressure phases in the XRD data above 40<!-- --> <!-- -->GPa, which clearly indicates the first order nature of the phase transition. The Raman spectroscopic studies showed an abrupt change in intensities and red shift of the highest intensity peak ~ 39<!-- --> <!-- -->GPa, thus corroborating the x-ray diffraction and ab-initio results. This shift is correlated with a coordination increase from 6 to 9 in Mo<sup>+6</sup> ions associated with this phase transition to <em>Cm</em> phase. This study also shows that β-ZnMoO<sub>4</sub> is an insulator with a direct band gap of 2.9<!-- --> <!-- -->eV at ambient pressure as determined from UV visible absorption spectroscopy making it an ideal material for photocatalytic applications. Our electronic calculations corroborate this finding.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"197 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142678179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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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