Pub Date : 2024-09-06DOI: 10.1016/j.mtcomm.2024.110347
Rabia Tuğçe Şahin, Ömer Faruk Atak, Arda Baran Burcak, Hadi Jahangiri, Amir Motallebzadeh, Umut Aydemir, Samira Mohagheghi
The addition of various reinforcing phases can improve the mechanical properties of copper. This study investigates the enhancement of the mechanical properties of copper by adding boron, focusing on overcoming the challenges associated with the homogeneous distribution of submicron/nanoscale secondary phases in metal matrix composites. Employing a combination of mechanical alloying and spark plasma sintering, a copper-boron composite containing 3 wt% boron was prepared. Scanning electron microscopy equipped with an electron backscatter diffraction detector and energy-dispersive X-ray spectroscopy was utilized to characterize the structure of the sintered samples and mechanically alloyed powder. A two-phase structure containing nano/submicron-sized boron distributed uniformly in the copper matrix was formed in the sintered sample. Instrumented micro-indentation tests were performed to characterize the mechanical behavior of the samples. The sintered composite sample exhibits significantly higher hardness than the sintered copper. The enhanced mechanical performance of the composite is primarily attributed to grain boundary strengthening and microstructural refinement, where nano/submicron-sized boron particles prevent grain growth and refine the microstructure, enhancing hardness and strength. Additionally, dispersion strengthening from hard boron particles and the presence of a high density of twin boundaries within the copper matrix increase resistance to dislocation motion and deformation, and further improving the material's mechanical properties. On the other hand, the composite sample exhibits increased electrical resistivity due to the boron’s role as electron scattering centers. Overall, this study provides a valuable strategy for the design and optimization of advanced copper-based composites with tailored mechanical and electrical properties.
添加各种增强相可以改善铜的机械性能。本研究通过添加硼来提高铜的机械性能，重点是克服金属基复合材料中亚微米/纳米级次生相均匀分布所带来的挑战。结合机械合金化和火花等离子烧结技术，制备了含硼 3 wt% 的铜硼复合材料。利用配备电子反向散射衍射探测器的扫描电子显微镜和能量色散 X 射线光谱分析了烧结样品和机械合金粉末的结构特征。烧结样品形成了两相结构，铜基体中均匀分布着纳米级/亚微米级的硼。为了描述样品的机械性能，我们进行了仪器显微压痕测试。烧结复合材料样品的硬度明显高于烧结铜。复合材料机械性能的提高主要归功于晶界强化和微结构细化，其中纳米/亚微米级的硼颗粒可防止晶粒长大并细化微结构，从而提高硬度和强度。此外，硬硼粒子的分散强化作用以及铜基体中高密度孪晶边界的存在增强了抗位错运动和变形的能力，进一步提高了材料的机械性能。另一方面，由于硼作为电子散射中心的作用，复合材料样品的电阻率增加。总之，这项研究为设计和优化具有定制机械和电气性能的先进铜基复合材料提供了有价值的策略。
{"title":"Characterization of a copper matrix composite reinforced with nano/submicron-sized boron fabricated via spark plasma sintering","authors":"Rabia Tuğçe Şahin, Ömer Faruk Atak, Arda Baran Burcak, Hadi Jahangiri, Amir Motallebzadeh, Umut Aydemir, Samira Mohagheghi","doi":"10.1016/j.mtcomm.2024.110347","DOIUrl":"https://doi.org/10.1016/j.mtcomm.2024.110347","url":null,"abstract":"The addition of various reinforcing phases can improve the mechanical properties of copper. This study investigates the enhancement of the mechanical properties of copper by adding boron, focusing on overcoming the challenges associated with the homogeneous distribution of submicron/nanoscale secondary phases in metal matrix composites. Employing a combination of mechanical alloying and spark plasma sintering, a copper-boron composite containing 3 wt% boron was prepared. Scanning electron microscopy equipped with an electron backscatter diffraction detector and energy-dispersive X-ray spectroscopy was utilized to characterize the structure of the sintered samples and mechanically alloyed powder. A two-phase structure containing nano/submicron-sized boron distributed uniformly in the copper matrix was formed in the sintered sample. Instrumented micro-indentation tests were performed to characterize the mechanical behavior of the samples. The sintered composite sample exhibits significantly higher hardness than the sintered copper. The enhanced mechanical performance of the composite is primarily attributed to grain boundary strengthening and microstructural refinement, where nano/submicron-sized boron particles prevent grain growth and refine the microstructure, enhancing hardness and strength. Additionally, dispersion strengthening from hard boron particles and the presence of a high density of twin boundaries within the copper matrix increase resistance to dislocation motion and deformation, and further improving the material's mechanical properties. On the other hand, the composite sample exhibits increased electrical resistivity due to the boron’s role as electron scattering centers. Overall, this study provides a valuable strategy for the design and optimization of advanced copper-based composites with tailored mechanical and electrical properties.","PeriodicalId":18477,"journal":{"name":"Materials Today Communications","volume":"5 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142268179","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 : 2024-09-05DOI: 10.1016/j.mtcomm.2024.110336
Lianqing Yu, Wenjing Xie, Xiaomeng Ji, Yaping Zhang, Haifeng Zhu
The availability of low-cost precious metal-free photocatalysts is critical for sustainable and large-scale hydrogen production. Constructing heterojunctions is considered as an effective strategy to enhance the transfer/separation of photo-induced charges. Nanoflower structures of ZnCdS can significantly enhance light absorption and increase the specific surface area available for reactions involving photo-generated carriers. Herein, MoS are attached to ZnCdS nanoflowers through electrostatic adsorption, forming a ZnCdS-MoS composite photocatalyst for hydrogen evolution reaction (HER). Under visible light irradiation, the ZCS-MoS-8 % photocatalyst demonstrates an impressive photocatalytic HER rate of 42.07 mmol·h·g, which is 5.8 times higher than that of the pure ZnCdS photocatalyst (outperforming many reported results). The MoS nanocrystals greatly benefit the transfer of photoinduced electrons to ZnCdS for proton reduction and facilitate the transfer of holes for water oxidation. The constructed ZnCdS-MoS photocatalyst for hydrogen evolution shows promising chemical and economic value.
{"title":"Anchoring MoS2 on ZnCdS to accelerate charge migration to promote photocatalytic water decomposition performance","authors":"Lianqing Yu, Wenjing Xie, Xiaomeng Ji, Yaping Zhang, Haifeng Zhu","doi":"10.1016/j.mtcomm.2024.110336","DOIUrl":"https://doi.org/10.1016/j.mtcomm.2024.110336","url":null,"abstract":"The availability of low-cost precious metal-free photocatalysts is critical for sustainable and large-scale hydrogen production. Constructing heterojunctions is considered as an effective strategy to enhance the transfer/separation of photo-induced charges. Nanoflower structures of ZnCdS can significantly enhance light absorption and increase the specific surface area available for reactions involving photo-generated carriers. Herein, MoS are attached to ZnCdS nanoflowers through electrostatic adsorption, forming a ZnCdS-MoS composite photocatalyst for hydrogen evolution reaction (HER). Under visible light irradiation, the ZCS-MoS-8 % photocatalyst demonstrates an impressive photocatalytic HER rate of 42.07 mmol·h·g, which is 5.8 times higher than that of the pure ZnCdS photocatalyst (outperforming many reported results). The MoS nanocrystals greatly benefit the transfer of photoinduced electrons to ZnCdS for proton reduction and facilitate the transfer of holes for water oxidation. The constructed ZnCdS-MoS photocatalyst for hydrogen evolution shows promising chemical and economic value.","PeriodicalId":18477,"journal":{"name":"Materials Today Communications","volume":"11 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142193534","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}
Hydrogen embrittlement is an inevitable scientific problem of zirconium cladding materials in service or accident conditions, since the hydride precipitation deteriorates the mechanical properties, and damages the structure integrity. Twin boundaries (TBs) are the common low-energy defects inside the grain, whereas their spatial correlation with hydrides has been controversial to now. Here, we combined the first principle calculation and multi-scale characterization to reveal that the low-energy TBs can act as the preferred precipitation site of hydride in Zr-4. Compared with common intergranular hydrides, TB hydrides maintain the orientation relationship with the adjacent α-Zr matrix and twin. These findings can guide grain boundary engineering strategies for optimizing the resistance to crack initiation in zirconium alloy.
{"title":"Spatial correlation behavior between hydride and low-energy twin boundaries in Zr-4","authors":"Huanzheng Sun, Baifeng Luan, Chao Sun, Chunrong Xu, Yan Zhang, Xiaoyong Zhu, Hongling Zhou","doi":"10.1016/j.mtcomm.2024.110339","DOIUrl":"https://doi.org/10.1016/j.mtcomm.2024.110339","url":null,"abstract":"Hydrogen embrittlement is an inevitable scientific problem of zirconium cladding materials in service or accident conditions, since the hydride precipitation deteriorates the mechanical properties, and damages the structure integrity. Twin boundaries (TBs) are the common low-energy defects inside the grain, whereas their spatial correlation with hydrides has been controversial to now. Here, we combined the first principle calculation and multi-scale characterization to reveal that the low-energy TBs can act as the preferred precipitation site of hydride in Zr-4. Compared with common intergranular hydrides, TB hydrides maintain the orientation relationship with the adjacent α-Zr matrix and twin. These findings can guide grain boundary engineering strategies for optimizing the resistance to crack initiation in zirconium alloy.","PeriodicalId":18477,"journal":{"name":"Materials Today Communications","volume":"148 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142193533","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 : 2024-09-05DOI: 10.1016/j.mtcomm.2024.110326
Xuan Zhang, Liang Zhang, Yuxuan Wan, Yasushi Shibuta, Xiaoxu Huang
Grain boundary (GB) segregation energy is an important factor affecting the segregation behavior of solute atoms and the mechanical properties of alloys. In this study, first-principles calculation combined with machine learning (ML) algorithms were used to calculate and predict the GB segregation energies of solute atoms in Al alloys. Five GB structures and 44 common solute atoms in aluminum were selected for the calculations, and a database of 924 groups describing the relationship between GB characteristics and GB segregation energy of solute atoms was constructed. Calculation results and feature importance analysis show that the atomic radius and Voronoi volume of solute atoms play significant roles in determining segregation energies. Nine ML algorithms, including three linear regression models, four decision tree models, a support vector regression model, and an artificial neural networks model, were employed to predict the GB segregation energy. The results indicate that increasing model complexity leads to an overall improved prediction accuracy. The performance of decision tree models is generally better than that of linear regression models. The artificial neural network model exhibits the highest performance, demonstrating a promising combination of accuracy and efficiency, and ten cross-validations confirmed the robustness and generalization ability of the model on the prediction task of GB segregation energy.
{"title":"Predicting the grain boundary segregation energy of solute atoms in aluminum by first-principles calculation and machine learning","authors":"Xuan Zhang, Liang Zhang, Yuxuan Wan, Yasushi Shibuta, Xiaoxu Huang","doi":"10.1016/j.mtcomm.2024.110326","DOIUrl":"https://doi.org/10.1016/j.mtcomm.2024.110326","url":null,"abstract":"Grain boundary (GB) segregation energy is an important factor affecting the segregation behavior of solute atoms and the mechanical properties of alloys. In this study, first-principles calculation combined with machine learning (ML) algorithms were used to calculate and predict the GB segregation energies of solute atoms in Al alloys. Five GB structures and 44 common solute atoms in aluminum were selected for the calculations, and a database of 924 groups describing the relationship between GB characteristics and GB segregation energy of solute atoms was constructed. Calculation results and feature importance analysis show that the atomic radius and Voronoi volume of solute atoms play significant roles in determining segregation energies. Nine ML algorithms, including three linear regression models, four decision tree models, a support vector regression model, and an artificial neural networks model, were employed to predict the GB segregation energy. The results indicate that increasing model complexity leads to an overall improved prediction accuracy. The performance of decision tree models is generally better than that of linear regression models. The artificial neural network model exhibits the highest performance, demonstrating a promising combination of accuracy and efficiency, and ten cross-validations confirmed the robustness and generalization ability of the model on the prediction task of GB segregation energy.","PeriodicalId":18477,"journal":{"name":"Materials Today Communications","volume":"62 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142193538","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 : 2024-09-05DOI: 10.1016/j.mtcomm.2024.110342
Zhengliang Deng, Yajun Wang, Ruihua Liu, Wenyu Li, Qiang Gan
In order to improve the overall performance of traditional thermite, Al/B/FeO composite thermites were synthesized using electrophoretic deposition technology. The morphology, structure, composition, thermal reaction properties, reaction process, and reaction activity were investigated using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), X-ray energy dispersive spectrometry (EDS), X-ray diffractometer (XRD), and simultaneous thermal analyzer (TG-DSC). The results indicate that the components of the prepared Al/B/FeO composites were uniformly distributed and closely interconnected, with the preparation process not altering the composition and structure of the components. Compared with Al/B/FeO thermite prepared by physical mixing and Al/FeO thermite by electrophoretic deposition, the Al/B/FeO thermite prepared by electrophoretic deposition exhibited a lower reaction onset temperature (524.9 ℃), higher heat release (1240.9 J·g), and greater reactivity (=168.3 kJ·mol). These findings underscore the significant enhancement effect of boron addition and the electrophoretic deposition method on the overall performance of Al/FeO thermite. Analysis of the reaction mechanism reveals that the Al/B/FeO composite thermites underwent a series of complex transformations, including thermite reactions, alloying reaction between Al and B, direct oxidation reactions of Al, B, Fe, and nitriding reaction of B, within the temperature range of thermal analysis from room temperature to 1100 ℃. These results provide crucial support for material innovation, performance optimization, and application expansion of thermites.
{"title":"Enhanced performance of Al/B/Fe2O3 composite thermite prepared via electrophoretic deposition technology","authors":"Zhengliang Deng, Yajun Wang, Ruihua Liu, Wenyu Li, Qiang Gan","doi":"10.1016/j.mtcomm.2024.110342","DOIUrl":"https://doi.org/10.1016/j.mtcomm.2024.110342","url":null,"abstract":"In order to improve the overall performance of traditional thermite, Al/B/FeO composite thermites were synthesized using electrophoretic deposition technology. The morphology, structure, composition, thermal reaction properties, reaction process, and reaction activity were investigated using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), X-ray energy dispersive spectrometry (EDS), X-ray diffractometer (XRD), and simultaneous thermal analyzer (TG-DSC). The results indicate that the components of the prepared Al/B/FeO composites were uniformly distributed and closely interconnected, with the preparation process not altering the composition and structure of the components. Compared with Al/B/FeO thermite prepared by physical mixing and Al/FeO thermite by electrophoretic deposition, the Al/B/FeO thermite prepared by electrophoretic deposition exhibited a lower reaction onset temperature (524.9 ℃), higher heat release (1240.9 J·g), and greater reactivity (=168.3 kJ·mol). These findings underscore the significant enhancement effect of boron addition and the electrophoretic deposition method on the overall performance of Al/FeO thermite. Analysis of the reaction mechanism reveals that the Al/B/FeO composite thermites underwent a series of complex transformations, including thermite reactions, alloying reaction between Al and B, direct oxidation reactions of Al, B, Fe, and nitriding reaction of B, within the temperature range of thermal analysis from room temperature to 1100 ℃. These results provide crucial support for material innovation, performance optimization, and application expansion of thermites.","PeriodicalId":18477,"journal":{"name":"Materials Today Communications","volume":"67 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142193535","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 : 2024-09-05DOI: 10.1016/j.mtcomm.2024.110338
Ke Wang, Xukai Ren, Yu Zhang, Guang Chen, Yaofeng Wu
This work investigates how accumulative strain and Cu content (45, 62, 77 wt%) impact the structural, mechanical, thermal, and electrical properties of the Al/Cu composite fabricated via the ARB technique. According to the results, an increase in the Cu wt% led to the rise of plastic instability emergence rate, tensile strength, microhardness, and electrical and thermal conductivity. Moreover, as the strain increased during ARB passes, the distribution of hard layers, strength, and microhardness of the composites increased while the elongation, electrical resistivity, and thermal conductivity decreased. The peak tensile strength reached 375 MPa in the fifth pass for Al/77Cu. However, the max electrical and thermal conductivity values of 69.5 % IACS and 180 W/m/K were achieved in the first pass for Al/77Cu. Examination of the fracture surfaces of the post-tensile test specimens indicated that the predominant fracture mode following the ARB process is a shear ductile fracture.
{"title":"The crucial role of accumulated strain and Cu content on the electrical, thermal, tensile, fracture, and microstructure characteristics of Al/Cu multi-layered composites subjected to SPD","authors":"Ke Wang, Xukai Ren, Yu Zhang, Guang Chen, Yaofeng Wu","doi":"10.1016/j.mtcomm.2024.110338","DOIUrl":"https://doi.org/10.1016/j.mtcomm.2024.110338","url":null,"abstract":"This work investigates how accumulative strain and Cu content (45, 62, 77 wt%) impact the structural, mechanical, thermal, and electrical properties of the Al/Cu composite fabricated via the ARB technique. According to the results, an increase in the Cu wt% led to the rise of plastic instability emergence rate, tensile strength, microhardness, and electrical and thermal conductivity. Moreover, as the strain increased during ARB passes, the distribution of hard layers, strength, and microhardness of the composites increased while the elongation, electrical resistivity, and thermal conductivity decreased. The peak tensile strength reached 375 MPa in the fifth pass for Al/77Cu. However, the max electrical and thermal conductivity values of 69.5 % IACS and 180 W/m/K were achieved in the first pass for Al/77Cu. Examination of the fracture surfaces of the post-tensile test specimens indicated that the predominant fracture mode following the ARB process is a shear ductile fracture.","PeriodicalId":18477,"journal":{"name":"Materials Today Communications","volume":"61 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142193532","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 : 2024-09-04DOI: 10.1016/j.mtcomm.2024.110321
Haodong Rao, Feng Jin, Jianguo Wang, Hai Wang, Jungang Nan, Dong Liu
Quantitative characterization of microtextured regions (MTRs) in Ti6242 billets and understanding their correlation with thermal processing are crucial for predicting dwell fatigue performance in aeroengine components. Three industrial-grade Ti6242 billets with 2, 5 and 8 α/β processing cycles were prepared. MTR characteristics—content, size, morphology, and orientation—were analyzed across radial locations (center, mid-radius, edge) using a novel MTR segmentation technique. Results show MTRs diminish with increased α/β processing cycle. In the billet with 2 cycles, MTR content decreases from center to edge, with average MTR size increasing gradually and maximum size rising sharply due to a few large MTRs at the edge. Variations in MTR characteristics across radial locations are linked to differing strain paths and levels. As the α/β processing cycles increase, MTR elimination at the edge relies on maximum cumulative effective strain, while at the center it relies on combined strain path effects of upsetting and cogging processes. MTRs at the mid-radius are the most difficult to eliminate. Low-cycle fatigue life is comparable among billets, but dwell fatigue is significantly poorer in the billet with 2 cycles, where the MTR morphologies are observed in the crack propagation region with sizes comparable to the average MTR size.
{"title":"Quantitative characterization of microtextured regions in Ti6242 billets and its impact on dwell fatigue performance","authors":"Haodong Rao, Feng Jin, Jianguo Wang, Hai Wang, Jungang Nan, Dong Liu","doi":"10.1016/j.mtcomm.2024.110321","DOIUrl":"https://doi.org/10.1016/j.mtcomm.2024.110321","url":null,"abstract":"Quantitative characterization of microtextured regions (MTRs) in Ti6242 billets and understanding their correlation with thermal processing are crucial for predicting dwell fatigue performance in aeroengine components. Three industrial-grade Ti6242 billets with 2, 5 and 8 α/β processing cycles were prepared. MTR characteristics—content, size, morphology, and orientation—were analyzed across radial locations (center, mid-radius, edge) using a novel MTR segmentation technique. Results show MTRs diminish with increased α/β processing cycle. In the billet with 2 cycles, MTR content decreases from center to edge, with average MTR size increasing gradually and maximum size rising sharply due to a few large MTRs at the edge. Variations in MTR characteristics across radial locations are linked to differing strain paths and levels. As the α/β processing cycles increase, MTR elimination at the edge relies on maximum cumulative effective strain, while at the center it relies on combined strain path effects of upsetting and cogging processes. MTRs at the mid-radius are the most difficult to eliminate. Low-cycle fatigue life is comparable among billets, but dwell fatigue is significantly poorer in the billet with 2 cycles, where the MTR morphologies are observed in the crack propagation region with sizes comparable to the average MTR size.","PeriodicalId":18477,"journal":{"name":"Materials Today Communications","volume":"219 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142193540","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 : 2024-09-04DOI: 10.1016/j.mtcomm.2024.110331
Mingguang Wu, Chen Wang, Yujun Zuo, Shuai Yang, Juzheng Zhang, Yi Luo
The uniaxial compressive strength (UCS) of the backfill is crucial for ensuring the stability and safety of the goaf. It can lead to the collapse of the goaf and subsidence changes in the ground surface. To accurately assess and predict the strength of phosphogypsum-based composite cementitious backfill, the effects of four cementitious material factors (quicklime, phosphogypsum, NaOH, and cement) on the strength of the backfill were investigated. A BP neural network strength prediction model for phosphogypsum-based composite cementitious backfill based on orthogonal tests was established. The changes in the strength of the internal structure of the backfill at different curing periods (7 days, 14 days, and 28 days) were analyzed using SEM-EDS tests. The results showed that the established orthogonal BP neural network prediction model had fast convergence speed and high prediction accuracy. The prediction model's correlation coefficient (R) was as high as 0.99903, and the relative error was within 5 %. The results of the grey correlation analysis indicate that the phosphogypsum content is the primary factor influencing the strength of the backfill. Furthermore, the change rule of backfill strength in response to varying cementitious material content has been elucidated. The internal strength of the backfill at different curing periods is primarily influenced by the formation of 3CaO • AlO • 3CaSO • 31 HO (AFt). The findings of these studies are of great significance for the evaluation and prediction of the strength of phosphogypsum-based cementitious composite backfill and provide strong support for further research in this field.
回填土的单轴抗压强度（UCS）对确保围堰的稳定性和安全性至关重要。回填土的单轴抗压强度（UCS）对地表的稳定和安全至关重要，它可能导致地表塌陷和地表沉降变化。为了准确评估和预测磷石膏基复合胶凝回填土的强度，研究了四种胶凝材料因素（生石灰、磷石膏、NaOH 和水泥）对回填土强度的影响。建立了基于正交试验的磷石膏基复合水泥基回填土 BP 神经网络强度预测模型。使用 SEM-EDS 测试分析了不同固化期（7 天、14 天和 28 天）回填土内部结构强度的变化。结果表明，所建立的正交 BP 神经网络预测模型收敛速度快，预测精度高。预测模型的相关系数（R）高达 0.99903，相对误差在 5%以内。灰色关联分析结果表明，磷石膏含量是影响回填土强度的主要因素。此外，还阐明了不同胶凝材料含量对回填土强度的影响变化规律。回填土在不同固化期的内部强度主要受 3CaO - AlO - 3CaSO - 31 HO (AFt) 形成的影响。这些研究结果对于评估和预测磷石膏基水泥基复合回填土的强度具有重要意义，并为该领域的进一步研究提供了有力支持。
{"title":"Study on strength prediction and strength change of Phosphogypsum-based composite cementitious backfill based on BP neural network","authors":"Mingguang Wu, Chen Wang, Yujun Zuo, Shuai Yang, Juzheng Zhang, Yi Luo","doi":"10.1016/j.mtcomm.2024.110331","DOIUrl":"https://doi.org/10.1016/j.mtcomm.2024.110331","url":null,"abstract":"The uniaxial compressive strength (UCS) of the backfill is crucial for ensuring the stability and safety of the goaf. It can lead to the collapse of the goaf and subsidence changes in the ground surface. To accurately assess and predict the strength of phosphogypsum-based composite cementitious backfill, the effects of four cementitious material factors (quicklime, phosphogypsum, NaOH, and cement) on the strength of the backfill were investigated. A BP neural network strength prediction model for phosphogypsum-based composite cementitious backfill based on orthogonal tests was established. The changes in the strength of the internal structure of the backfill at different curing periods (7 days, 14 days, and 28 days) were analyzed using SEM-EDS tests. The results showed that the established orthogonal BP neural network prediction model had fast convergence speed and high prediction accuracy. The prediction model's correlation coefficient (R) was as high as 0.99903, and the relative error was within 5 %. The results of the grey correlation analysis indicate that the phosphogypsum content is the primary factor influencing the strength of the backfill. Furthermore, the change rule of backfill strength in response to varying cementitious material content has been elucidated. The internal strength of the backfill at different curing periods is primarily influenced by the formation of 3CaO • AlO • 3CaSO • 31 HO (AFt). The findings of these studies are of great significance for the evaluation and prediction of the strength of phosphogypsum-based cementitious composite backfill and provide strong support for further research in this field.","PeriodicalId":18477,"journal":{"name":"Materials Today Communications","volume":"36 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142193536","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 : 2024-09-04DOI: 10.1016/j.mtcomm.2024.110318
Gangtai Zhang, Tingting Bai, Guodong Feng, Junjie He
Utilizing the CALYPSO algorithm in conjunction with first-principles calculations, we theoretically explore the possible crystal structures of TaB and TaB. The calculated results show that the phase of TaB and 2 phase of TaB are the most thermodynamically favored structures among the predicted and substitute structures, and they can be synthesized at ambient pressure. The calculations of the phonon spectra and elastic constants demonstrate that the two predicted phases are dynamically and mechanically stable. The exceptional bulk modulus and significant hardness of these two materials verify that they are potentially ultra-incompressible and superhard materials. Additionally, the elastic anisotropy for the TaB and 2-TaB is also studied by applying sever good anisotropy indices and visual representations of the Young’s and bulk moduli in two and three dimensions. The in-depth analysis of the electronic structure and chemical bonding reveal that the robust covalent interactions of both B-B and B-Ta atoms within these phases mainly contribute to their stability and high hardness. These results will offer a theoretical foundation for the experimental synthesis of these two new materials.
{"title":"Crystal structures and mechanical properties of TaB5 and TaB6 from first-principles calculations","authors":"Gangtai Zhang, Tingting Bai, Guodong Feng, Junjie He","doi":"10.1016/j.mtcomm.2024.110318","DOIUrl":"https://doi.org/10.1016/j.mtcomm.2024.110318","url":null,"abstract":"Utilizing the CALYPSO algorithm in conjunction with first-principles calculations, we theoretically explore the possible crystal structures of TaB and TaB. The calculated results show that the phase of TaB and 2 phase of TaB are the most thermodynamically favored structures among the predicted and substitute structures, and they can be synthesized at ambient pressure. The calculations of the phonon spectra and elastic constants demonstrate that the two predicted phases are dynamically and mechanically stable. The exceptional bulk modulus and significant hardness of these two materials verify that they are potentially ultra-incompressible and superhard materials. Additionally, the elastic anisotropy for the TaB and 2-TaB is also studied by applying sever good anisotropy indices and visual representations of the Young’s and bulk moduli in two and three dimensions. The in-depth analysis of the electronic structure and chemical bonding reveal that the robust covalent interactions of both B-B and B-Ta atoms within these phases mainly contribute to their stability and high hardness. These results will offer a theoretical foundation for the experimental synthesis of these two new materials.","PeriodicalId":18477,"journal":{"name":"Materials Today Communications","volume":"11 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142193539","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 : 2024-09-04DOI: 10.1016/j.mtcomm.2024.110293
Jie Qiao, Yigang Lv, Hui Peng, Weiwei Han, Bei Pan, Bai Zhang
Geopolymers derived from various aluminosilicate materials are significantly impacted by the composition of raw materials and activators. However, existing research has not clearly elucidated the relationship and evolution laws between raw material composition, activator alkalinity, and geopolymer properties. To address this gap, this study investigates the effects of the fly ash/metakaolin ratio and activator concentration on the mechanical performance and microstructures of fly ash-metakaolin (FM) based geopolymer pastes. This comprehensive approach aims to uncover the evolutionary patterns of material properties and reveal the reaction mechanism and influencing factors of geopolymer derived from fly ash and metakaolin. The study revealed that an increase in fly ash content led to a gradual decrease in the total heat release of FM-based geopolymer pastes, indicating reduced hydration reaction degree and subsequent compressive strength decline. Additionally, higher residual alkali content in the pore solution contributed to elevated pH values. Increasing activator concentration effectively enhanced geopolymer hydration reactions, with compressive strength correlating with total heat release. Varied activator concentrations yielded similar final pH values in the pore solution. FM-based geopolymer pastes exhibited numerous nano-sized pore structures, with paste compactness decreasing as fly ash content increased, while total porosity decreased with higher activator concentrations, resulting in a denser microstructure. Hydration products of FM-based geopolymer pastes primarily comprised amorphous aluminosilicate gel, quartz, mullite, and partially unreacted sodium silicate crystals.
{"title":"Performance and characterization of fly ash-metakaolin-based geopolymer pastes","authors":"Jie Qiao, Yigang Lv, Hui Peng, Weiwei Han, Bei Pan, Bai Zhang","doi":"10.1016/j.mtcomm.2024.110293","DOIUrl":"https://doi.org/10.1016/j.mtcomm.2024.110293","url":null,"abstract":"Geopolymers derived from various aluminosilicate materials are significantly impacted by the composition of raw materials and activators. However, existing research has not clearly elucidated the relationship and evolution laws between raw material composition, activator alkalinity, and geopolymer properties. To address this gap, this study investigates the effects of the fly ash/metakaolin ratio and activator concentration on the mechanical performance and microstructures of fly ash-metakaolin (FM) based geopolymer pastes. This comprehensive approach aims to uncover the evolutionary patterns of material properties and reveal the reaction mechanism and influencing factors of geopolymer derived from fly ash and metakaolin. The study revealed that an increase in fly ash content led to a gradual decrease in the total heat release of FM-based geopolymer pastes, indicating reduced hydration reaction degree and subsequent compressive strength decline. Additionally, higher residual alkali content in the pore solution contributed to elevated pH values. Increasing activator concentration effectively enhanced geopolymer hydration reactions, with compressive strength correlating with total heat release. Varied activator concentrations yielded similar final pH values in the pore solution. FM-based geopolymer pastes exhibited numerous nano-sized pore structures, with paste compactness decreasing as fly ash content increased, while total porosity decreased with higher activator concentrations, resulting in a denser microstructure. Hydration products of FM-based geopolymer pastes primarily comprised amorphous aluminosilicate gel, quartz, mullite, and partially unreacted sodium silicate crystals.","PeriodicalId":18477,"journal":{"name":"Materials Today Communications","volume":"61 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142193541","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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