Pub Date : 2024-09-06DOI: 10.3389/fmats.2024.1367754
Ashwini Kumar, Poorva Sharma, Fujun Qiu
This study investigates the synthesis, structural analysis, and microwave dielectric characteristics of ZnZrNb2O8 ceramics, prepared via solid-state reaction method and subjected to sintering at temperatures ranging from 1,000°C to 1,200°C for 4 h. X-ray diffraction (XRD) analysis confirms the successful formation of ZnZrNb2O8 phase, with a monoclinic wolframite phase. Scanning electron microscopy (SEM) investigations unveil microstructural features such as grain size and porosity, reveals material’s morphological details. Dielectric properties conducted in the microwave frequency regime show a correlation between dielectric constant (εr) and relative density of the ceramics. Importantly, the ceramics exhibited a suitable dielectric constant and low dielectric loss, indicative of their suitability for microwave applications. Remarkably, ZnZrNb2O8 ceramics sintered at 1,150°C for 4 h exhibit excellent microwave dielectric properties (εr = 27.2, Q × f = 54,500 GHz, and τf = −60 ppm/°C). These findings underscore the potential of ZnZrNb2O8 ceramics as advanced materials for high-frequency applications, including filters, resonators, and other microwave devices, thus contributing significantly to the advancement of next-generation telecommunications technologies.
{"title":"Structure characteristics and microwave dielectric properties of ZnZrNb2O8 oxide ceramics","authors":"Ashwini Kumar, Poorva Sharma, Fujun Qiu","doi":"10.3389/fmats.2024.1367754","DOIUrl":"https://doi.org/10.3389/fmats.2024.1367754","url":null,"abstract":"This study investigates the synthesis, structural analysis, and microwave dielectric characteristics of ZnZrNb<jats:sub>2</jats:sub>O<jats:sub>8</jats:sub> ceramics, prepared via solid-state reaction method and subjected to sintering at temperatures ranging from 1,000°C to 1,200°C for 4 h. X-ray diffraction (XRD) analysis confirms the successful formation of ZnZrNb<jats:sub>2</jats:sub>O<jats:sub>8</jats:sub> phase, with a monoclinic wolframite phase. Scanning electron microscopy (SEM) investigations unveil microstructural features such as grain size and porosity, reveals material’s morphological details. Dielectric properties conducted in the microwave frequency regime show a correlation between dielectric constant (<jats:italic>ε</jats:italic><jats:sub><jats:italic>r</jats:italic></jats:sub>) and relative density of the ceramics. Importantly, the ceramics exhibited a suitable dielectric constant and low dielectric loss, indicative of their suitability for microwave applications. Remarkably, ZnZrNb<jats:sub>2</jats:sub>O<jats:sub>8</jats:sub> ceramics sintered at 1,150°C for 4 h exhibit excellent microwave dielectric properties (<jats:italic>ε</jats:italic><jats:sub><jats:italic>r</jats:italic></jats:sub> = 27.2, <jats:italic>Q</jats:italic> × <jats:italic>f</jats:italic> = 54,500 GHz, and τ<jats:sub>f</jats:sub> = −60 ppm/°C). These findings underscore the potential of ZnZrNb<jats:sub>2</jats:sub>O<jats:sub>8</jats:sub> ceramics as advanced materials for high-frequency applications, including filters, resonators, and other microwave devices, thus contributing significantly to the advancement of next-generation telecommunications technologies.","PeriodicalId":12524,"journal":{"name":"Frontiers in Materials","volume":"6 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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: 10.3389/fmats.2024.1467134
Junkai Yao, Degou Cai, Ke Su, Hongye Yan
Expansive soils, known for their significant volume change with variations in moisture content, are widely distributed around the globe. Due to their swelling properties, expansive soils pose significant engineering challenges, especially in rapidly developing countries like China. This study aims to investigate the swelling mechanisms of expansive soils, focusing on the influence of crack characteristics on swelling behavior. The research methodology includes field investigations, laboratory experiments, and theoretical modeling. By comprehensively considering crack rate, dry density, initial moisture content, and overburden load, a nonlinear regression swelling model is proposed in this research. The degree of crack development in expansive soils is quantitatively characterized by the content of filling materials, leading to the establishment of a crack rate model for expansive soils. Swelling tests on expansive soils with different crack contents were conducted. The results show that the swelling rate is negatively correlated with the initial moisture content and positively correlated with dry density and crack rate. Additionally, the larger the crack rate, the more significant the change in the swelling rate. Furthermore, model validation confirms that this nonlinear regression model accurately describes the relationship between swelling rate and influencing factors. It offers a more precise prediction tool for infrastructure design and maintenance in expansive soil areas, advancing geotechnical engineering practices.
{"title":"Nonlinear regression modeling of swelling characteristics in cracked expansive soil: integrating crack, moisture, density, and load effect","authors":"Junkai Yao, Degou Cai, Ke Su, Hongye Yan","doi":"10.3389/fmats.2024.1467134","DOIUrl":"https://doi.org/10.3389/fmats.2024.1467134","url":null,"abstract":"Expansive soils, known for their significant volume change with variations in moisture content, are widely distributed around the globe. Due to their swelling properties, expansive soils pose significant engineering challenges, especially in rapidly developing countries like China. This study aims to investigate the swelling mechanisms of expansive soils, focusing on the influence of crack characteristics on swelling behavior. The research methodology includes field investigations, laboratory experiments, and theoretical modeling. By comprehensively considering crack rate, dry density, initial moisture content, and overburden load, a nonlinear regression swelling model is proposed in this research. The degree of crack development in expansive soils is quantitatively characterized by the content of filling materials, leading to the establishment of a crack rate model for expansive soils. Swelling tests on expansive soils with different crack contents were conducted. The results show that the swelling rate is negatively correlated with the initial moisture content and positively correlated with dry density and crack rate. Additionally, the larger the crack rate, the more significant the change in the swelling rate. Furthermore, model validation confirms that this nonlinear regression model accurately describes the relationship between swelling rate and influencing factors. It offers a more precise prediction tool for infrastructure design and maintenance in expansive soil areas, advancing geotechnical engineering practices.","PeriodicalId":12524,"journal":{"name":"Frontiers in Materials","volume":"297 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221296","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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: 10.3389/fmats.2024.1410542
Xiaoying Zhang, Rong Chang, Zhixiang Xu, Jie Wang, Zhibing Tan
This article conducts experimental research on the influencing factors of the anti-skid performance testing system SCRIM for asphalt pavement. Studied the distribution pattern of anti-skid performance test results of the testing system under different testing speeds, test tires, temperature, water film thickness, test wheel position, tire wear degree, and other factors. Revealed the influence law of various influencing factors on the anti-skid performance of asphalt pavement. The test results indicate that the SFC test value decreases with the increase of vehicle speed. The test results of tires made of different materials vary greatly, and tires with wear exceeding 3 mm cannot be used for testing. The influence of water film thickness on the measured values varies depending on the SFC level. The SFC measurement value of the normal trajectory of the vehicle’s driving wheel track is the smallest, and the measurement value of the left trajectory is greater than that of the right trajectory. The SFC measurement decreases as the tire wear increases.
{"title":"Research on the influencing factors of anti-skid performance evaluation of asphalt pavement based on lateral force testing system","authors":"Xiaoying Zhang, Rong Chang, Zhixiang Xu, Jie Wang, Zhibing Tan","doi":"10.3389/fmats.2024.1410542","DOIUrl":"https://doi.org/10.3389/fmats.2024.1410542","url":null,"abstract":"This article conducts experimental research on the influencing factors of the anti-skid performance testing system SCRIM for asphalt pavement. Studied the distribution pattern of anti-skid performance test results of the testing system under different testing speeds, test tires, temperature, water film thickness, test wheel position, tire wear degree, and other factors. Revealed the influence law of various influencing factors on the anti-skid performance of asphalt pavement. The test results indicate that the SFC test value decreases with the increase of vehicle speed. The test results of tires made of different materials vary greatly, and tires with wear exceeding 3 mm cannot be used for testing. The influence of water film thickness on the measured values varies depending on the SFC level. The SFC measurement value of the normal trajectory of the vehicle’s driving wheel track is the smallest, and the measurement value of the left trajectory is greater than that of the right trajectory. The SFC measurement decreases as the tire wear increases.","PeriodicalId":12524,"journal":{"name":"Frontiers in Materials","volume":"111 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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: 10.3389/fmats.2024.1467087
Jinglu Zhang, An He, Yu Liu, Shao-Bo Kang
This paper presents experimental and numerical studies on compression behaviour of equal-leg steel angles with bolted connection and subjected to local defect at the bolt hole. To simulate corrosion, a mechanical cutting method was used in the experimental test to increase the diameter of bolt holes, and a total of 18 steel angles were investigated in the study. The parameters considered included the slenderness and the diameter of bolt holes. The slendernesses of steel angles were 80 and 140, and the diameter of bolt holes ranged from 21.5 to 27.5 mm. Additionally, numerical models were established for the steel angles. The accuracy of the numerical model was verified by comparing experimental data with numerical results. Based on the validated numerical model, a parametric analysis was conducted to quantitatively assess the influences of the slenderness and the diameter of bolt holes on the load capacity of specimens against global buckling. Experimental and numerical results showed that the defect at the bolt hole affected the load capacity of specimens when the diameter of the bolt hole was increased to 27.5 mm and the slenderness was not greater than 100.
{"title":"Compression behaviour of Q355 steel angles with local defect at bolt holes","authors":"Jinglu Zhang, An He, Yu Liu, Shao-Bo Kang","doi":"10.3389/fmats.2024.1467087","DOIUrl":"https://doi.org/10.3389/fmats.2024.1467087","url":null,"abstract":"This paper presents experimental and numerical studies on compression behaviour of equal-leg steel angles with bolted connection and subjected to local defect at the bolt hole. To simulate corrosion, a mechanical cutting method was used in the experimental test to increase the diameter of bolt holes, and a total of 18 steel angles were investigated in the study. The parameters considered included the slenderness and the diameter of bolt holes. The slendernesses of steel angles were 80 and 140, and the diameter of bolt holes ranged from 21.5 to 27.5 mm. Additionally, numerical models were established for the steel angles. The accuracy of the numerical model was verified by comparing experimental data with numerical results. Based on the validated numerical model, a parametric analysis was conducted to quantitatively assess the influences of the slenderness and the diameter of bolt holes on the load capacity of specimens against global buckling. Experimental and numerical results showed that the defect at the bolt hole affected the load capacity of specimens when the diameter of the bolt hole was increased to 27.5 mm and the slenderness was not greater than 100.","PeriodicalId":12524,"journal":{"name":"Frontiers in Materials","volume":"58 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper explored the effects of various amounts of cellulose nanocrystals (CNCs), namely 0%, 0.1%, 0.2%, and 0.4% of binder weight, on the rheology, pore structure, mechanical properties, and 3D distribution of fibers of an engineered cementitious composite (ECC). The two rheological parameters, namely the yield stress and plastic viscosity, of the matrix containing the CNCs increased. Low-field nuclear magnetic resonance (LF-NMR) analysis, as a non-destructive method, proved that the addition of the CNCs to the ECC could reduce the porosity of the material and refine its pore size distribution. The addition of the CNCs enhanced the compressive strength of the ECC by 19.6%–33%. The results from uniaxial tensile tests showed incorporating the CNCs into the matrix could enhance the initial cracking strength and ultimate tensile strength of the ECC but reduce their tensile strain-hardening capacity. The optimal addition of 0.1% CNCs could effectively offset the decrease in strength due to increasing FA content, and maintain a relatively high level of tensile strain capacity of over 3%. Finally, X-ray micro-computed tomography (micro-CT) with ORS Dragonfly software was employed to reconstruct 3D images of the ECC to present the improvement in the fiber distribution due to the addition of the CNCs.
{"title":"A preliminary investigation of incorporating cellulose nanocrystals into engineered cementitious composites","authors":"Xiao Yang, Jian-Guo Ren, Lian-Xu Li, Zhen Wang, Qi-Hang Zhang, Qiao-Ling Liu","doi":"10.3389/fmats.2024.1443517","DOIUrl":"https://doi.org/10.3389/fmats.2024.1443517","url":null,"abstract":"This paper explored the effects of various amounts of cellulose nanocrystals (CNCs), namely 0%, 0.1%, 0.2%, and 0.4% of binder weight, on the rheology, pore structure, mechanical properties, and 3D distribution of fibers of an engineered cementitious composite (ECC). The two rheological parameters, namely the yield stress and plastic viscosity, of the matrix containing the CNCs increased. Low-field nuclear magnetic resonance (LF-NMR) analysis, as a non-destructive method, proved that the addition of the CNCs to the ECC could reduce the porosity of the material and refine its pore size distribution. The addition of the CNCs enhanced the compressive strength of the ECC by 19.6%–33%. The results from uniaxial tensile tests showed incorporating the CNCs into the matrix could enhance the initial cracking strength and ultimate tensile strength of the ECC but reduce their tensile strain-hardening capacity. The optimal addition of 0.1% CNCs could effectively offset the decrease in strength due to increasing FA content, and maintain a relatively high level of tensile strain capacity of over 3%. Finally, X-ray micro-computed tomography (micro-CT) with ORS Dragonfly software was employed to reconstruct 3D images of the ECC to present the improvement in the fiber distribution due to the addition of the CNCs.","PeriodicalId":12524,"journal":{"name":"Frontiers in Materials","volume":"39 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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: 10.3389/fmats.2024.1452773
Bo Wang, Wangyun Li, Kailin Pan, Wei Huang, Yubing Gong
The shear fatigue performance and fracture behavior of microscale ball grid array (BGA) structure Cu/Sn-3.0Ag-0.5Cu/Cu solder joints with different heights (500 μm, 300 μm, and 100 μm) with increasing current density (from 6.0 × 103 to 1.1 × 104 A/cm2) were investigated systematically. The results reveal that the fatigue life of solder joints decreases with increasing current density, while increasing with decreasing the height of solder joints. The location of fatigue fracture shifts from solder matrix to the interface between solder and intermetallic compound (IMC) layer for those with heights of 500 μm and 300 μm with increasing current density, in which the interfacial fracture is triggered by current crowding at the groove of the IMC layer and driven by mismatch strain at the solder/IMC layer interface; while, the fatigue fracture all occurs in the solder matrix for solder joints with a height of 100 μm. Moreover, the fracture in solder matrix of solder joints with heights of 500 μm and 300 μm exhibits an arc-shape fracture path, while a linear path for those with a height of 100 μm. These fracture paths are consistent with the concentration distribution region of plastic strain energy in solder joints.
{"title":"Size dependence on shear fatigue and fracture behavior of ball grid array structure Cu/Sn–3.0Ag–0.5Cu/Cu solder joints under current stressing","authors":"Bo Wang, Wangyun Li, Kailin Pan, Wei Huang, Yubing Gong","doi":"10.3389/fmats.2024.1452773","DOIUrl":"https://doi.org/10.3389/fmats.2024.1452773","url":null,"abstract":"The shear fatigue performance and fracture behavior of microscale ball grid array (BGA) structure Cu/Sn-3.0Ag-0.5Cu/Cu solder joints with different heights (500 μm, 300 μm, and 100 μm) with increasing current density (from 6.0 × 10<jats:sup>3</jats:sup> to 1.1 × 10<jats:sup>4</jats:sup> A/cm<jats:sup>2</jats:sup>) were investigated systematically. The results reveal that the fatigue life of solder joints decreases with increasing current density, while increasing with decreasing the height of solder joints. The location of fatigue fracture shifts from solder matrix to the interface between solder and intermetallic compound (IMC) layer for those with heights of 500 μm and 300 μm with increasing current density, in which the interfacial fracture is triggered by current crowding at the groove of the IMC layer and driven by mismatch strain at the solder/IMC layer interface; while, the fatigue fracture all occurs in the solder matrix for solder joints with a height of 100 μm. Moreover, the fracture in solder matrix of solder joints with heights of 500 μm and 300 μm exhibits an arc-shape fracture path, while a linear path for those with a height of 100 μm. These fracture paths are consistent with the concentration distribution region of plastic strain energy in solder joints.","PeriodicalId":12524,"journal":{"name":"Frontiers in Materials","volume":"10 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2024-09-03DOI: 10.3389/fmats.2024.1401816
Peng Wang, Fei Wang, Mingquan Ma
Ordinary cement mortar is commonly used in building engineering due to its high strength, affordability, and easy access to raw materials. However, it suffers from high shrinkage and poor impermeability, which result in reduced building service life and significant carbon dioxide emissions during production. Polymer additives have been found to enhance the mechanical properties of cement mortar, leading to increased interest in polymer cement mortar by researchers. This study collected and analyzed 420 papers published between 1995 and 2023 in the field of polymer cement mortar. The analysis included publication trends, author cooperation networks, national cooperation networks, published journals, co-citation of references, and keywords. The findings reveal a rapid publication growth from 2018 to 2023, with China making the most significant contribution in this field. Among the scholars, Ru Wang has published the highest number of articles in the field of polymer cement mortar, while Ohama’s papers have been cited the most. The journal with the most articles is Construction and Building Materials. Research in polymer cement mortar focuses on mechanical properties, performance, hydration process, microstructure, and other related aspects. The reinforcement effect of polymer-modified cement mortar on reinforced concrete and applying superabsorbent polymer-modified cement mortar and polymer fiber in cement mortar have emerged as recent research frontiers. This study can help scholars quickly identify high-quality references and research frontiers in the field of polymer cement mortar while also providing research directions and ideas.
{"title":"The research progress and Hotspot analysis of polymer cement mortar based on bibliometrics","authors":"Peng Wang, Fei Wang, Mingquan Ma","doi":"10.3389/fmats.2024.1401816","DOIUrl":"https://doi.org/10.3389/fmats.2024.1401816","url":null,"abstract":"Ordinary cement mortar is commonly used in building engineering due to its high strength, affordability, and easy access to raw materials. However, it suffers from high shrinkage and poor impermeability, which result in reduced building service life and significant carbon dioxide emissions during production. Polymer additives have been found to enhance the mechanical properties of cement mortar, leading to increased interest in polymer cement mortar by researchers. This study collected and analyzed 420 papers published between 1995 and 2023 in the field of polymer cement mortar. The analysis included publication trends, author cooperation networks, national cooperation networks, published journals, co-citation of references, and keywords. The findings reveal a rapid publication growth from 2018 to 2023, with China making the most significant contribution in this field. Among the scholars, Ru Wang has published the highest number of articles in the field of polymer cement mortar, while Ohama’s papers have been cited the most. The journal with the most articles is Construction and Building Materials. Research in polymer cement mortar focuses on mechanical properties, performance, hydration process, microstructure, and other related aspects. The reinforcement effect of polymer-modified cement mortar on reinforced concrete and applying superabsorbent polymer-modified cement mortar and polymer fiber in cement mortar have emerged as recent research frontiers. This study can help scholars quickly identify high-quality references and research frontiers in the field of polymer cement mortar while also providing research directions and ideas.","PeriodicalId":12524,"journal":{"name":"Frontiers in Materials","volume":"60 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this groundbreaking study, we unveil the remarkable structural, electronic, and optical Properties of the newly discovered double perovskite material, K2AgBiI6, presenting a paradigm shift in materials science. The unique crystal structure and diverse atomic interactions inherent in this double perovskite make it an up-and-coming candidate for various technological applications, particularly in photovoltaics; owing to its stability and resistance to heat and humidity, we aim to shed light on the extraordinary potential of K2AgBiI6. Our study provides valuable insights for researchers engaged in tailored material design. We anticipate that the exceptional electronic properties of K2AgBiI6 will not only redefine the boundaries of materials engineering but also catalyze unprecedented advances in sustainable technology. Employing the powerful computational tool CASTEP, we conducted detailed electronic structure calculations within the framework of Density Functional Theory (DFT) to unravel the electronic properties of the double perovskite K2AgBiI6. Our investigation thoroughly explored structural properties, band structure, total density of states (DOS), and partial density of states (PDOS). Furthermore, we systematically examined the influence of different exchange-correlation functionals, including LDA, GGA, and m-GGA, on the electronic and optical features of the material by presenting a comparative analysis of these approximations.
{"title":"Investigating the structural, electronic, and optical properties of the novel double perovskite K2AgBiI6 using DFT","authors":"Mohamed Karouchi, Abdelkebir Ejjabli, Omar Bajjou, Jamal Guerroum, Mohamed Al-Hattab, Mohamed A. Basyooni-M. Kabatas, Khalid Rahmani, Youssef Lachtioui","doi":"10.3389/fmats.2024.1448400","DOIUrl":"https://doi.org/10.3389/fmats.2024.1448400","url":null,"abstract":"In this groundbreaking study, we unveil the remarkable structural, electronic, and optical Properties of the newly discovered double perovskite material, K<jats:sub>2</jats:sub>AgBiI<jats:sub>6</jats:sub>, presenting a paradigm shift in materials science. The unique crystal structure and diverse atomic interactions inherent in this double perovskite make it an up-and-coming candidate for various technological applications, particularly in photovoltaics; owing to its stability and resistance to heat and humidity, we aim to shed light on the extraordinary potential of K<jats:sub>2</jats:sub>AgBiI<jats:sub>6</jats:sub>. Our study provides valuable insights for researchers engaged in tailored material design. We anticipate that the exceptional electronic properties of K<jats:sub>2</jats:sub>AgBiI<jats:sub>6</jats:sub> will not only redefine the boundaries of materials engineering but also catalyze unprecedented advances in sustainable technology. Employing the powerful computational tool CASTEP, we conducted detailed electronic structure calculations within the framework of Density Functional Theory (DFT) to unravel the electronic properties of the double perovskite K<jats:sub>2</jats:sub>AgBiI<jats:sub>6</jats:sub>. Our investigation thoroughly explored structural properties, band structure, total density of states (DOS), and partial density of states (PDOS). Furthermore, we systematically examined the influence of different exchange-correlation functionals, including LDA, GGA, and m-GGA, on the electronic and optical features of the material by presenting a comparative analysis of these approximations.","PeriodicalId":12524,"journal":{"name":"Frontiers in Materials","volume":"39 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
2.5D package realizes the interconnection of multiple dies through Si interposers, which can greatly improve the data transmission rate between dies. However, its multi-layer structure and high package density also place higher reliability requirements on the interconnection structure. As a key structure for interconnection, copper pillar bump (CPB) has small size, high heat generation, and thermal mismatch with silicon chips. The thermal fatigue failure of CPB has gradually become the main failure mode in 2.5D package. Due to the small size of CPB and the large proportion of intermetallic compound (IMC) layers, the lifetime prediction method of spherical solder joints is no longer suitable for CPB. Therefore, it is necessary to establish a fatigue lifetime prediction method for CPB. This paper establishes a method for obtaining the lifetime of CPB based on the basic theory of fatigue crack propagation. Using the extended finite element simulation method, the crack propagation lifetime of CPB under thermal cycling was obtained, and the influence of different IMC layer thickness on the fatigue lifetime of CPB was analyzed. The results indicated that the fatigue lifetime of cracks propagating in the IMC layer is lower than that of cracks propagating in the solder layer, and an increase in the thickness of the IMC layer leads to a significant decrease in the fatigue lifetime of CPB. The lifetime prediction method for CPB proposed in this paper can be used for reliability evaluation of 2.5D package, and has certain reference value for the study of the lifetime of CPB.
{"title":"Lifetime prediction of copper pillar bumps based on fatigue crack propagation","authors":"Yuege Zhou, Qingsheng Liu, Tengfei Ma, Shupeng Li, Xinyu Zhang","doi":"10.3389/fmats.2024.1470365","DOIUrl":"https://doi.org/10.3389/fmats.2024.1470365","url":null,"abstract":"2.5D package realizes the interconnection of multiple dies through Si interposers, which can greatly improve the data transmission rate between dies. However, its multi-layer structure and high package density also place higher reliability requirements on the interconnection structure. As a key structure for interconnection, copper pillar bump (CPB) has small size, high heat generation, and thermal mismatch with silicon chips. The thermal fatigue failure of CPB has gradually become the main failure mode in 2.5D package. Due to the small size of CPB and the large proportion of intermetallic compound (IMC) layers, the lifetime prediction method of spherical solder joints is no longer suitable for CPB. Therefore, it is necessary to establish a fatigue lifetime prediction method for CPB. This paper establishes a method for obtaining the lifetime of CPB based on the basic theory of fatigue crack propagation. Using the extended finite element simulation method, the crack propagation lifetime of CPB under thermal cycling was obtained, and the influence of different IMC layer thickness on the fatigue lifetime of CPB was analyzed. The results indicated that the fatigue lifetime of cracks propagating in the IMC layer is lower than that of cracks propagating in the solder layer, and an increase in the thickness of the IMC layer leads to a significant decrease in the fatigue lifetime of CPB. The lifetime prediction method for CPB proposed in this paper can be used for reliability evaluation of 2.5D package, and has certain reference value for the study of the lifetime of CPB.","PeriodicalId":12524,"journal":{"name":"Frontiers in Materials","volume":"297 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper investigated the dynamic mechanical properties of CO2-cured foam concrete under varying conditions, focusing on the effects of foam admixture and fiber reinforcement. The study tends to enrich the knowledge regarding the performance of CO2-cured foam concrete under different loading rates, especially in relation to density and matrix strength. The foam admixture of the specimens ranges from 26% to 55%, achieving density from 600 kg/m3 to 1,000 kg/m3. The specimens were loaded at strain rates from 80 s-1 to 398 s-1. Experimental results revealed the dynamic elastic modulus, dynamic compressive strength, and Dynamic Increase Factor (DIF) showed a strong correlation with the foam admixture and density. In addition, the incorporation of polypropylene (PP) fibers effectively improved the mechanical behavior of the foam concrete, achieving up to a 17% increase in dynamic compressive strength. This comprehensive analysis highlights the critical role of foam admixture and fiber reinforcement in determining the dynamic properties of CO2-cured foam concrete and provides valuable insights for optimizing the dynamic performance of foam concrete in various construction applications.
{"title":"Dynamic properties of CO2-cured foam concrete at different loading rates: Effect of the foam admixtures and addition of polypropylene fiber","authors":"Yunlin Liu, Shangwei Huo, Jiali Fu, Tingbo Shi, Dong Guo","doi":"10.3389/fmats.2024.1445848","DOIUrl":"https://doi.org/10.3389/fmats.2024.1445848","url":null,"abstract":"This paper investigated the dynamic mechanical properties of CO<jats:sub>2</jats:sub>-cured foam concrete under varying conditions, focusing on the effects of foam admixture and fiber reinforcement. The study tends to enrich the knowledge regarding the performance of CO<jats:sub>2</jats:sub>-cured foam concrete under different loading rates, especially in relation to density and matrix strength. The foam admixture of the specimens ranges from 26% to 55%, achieving density from 600 kg/m<jats:sup>3</jats:sup> to 1,000 kg/m<jats:sup>3</jats:sup>. The specimens were loaded at strain rates from 80 s<jats:sup>-1</jats:sup> to 398 s<jats:sup>-1</jats:sup>. Experimental results revealed the dynamic elastic modulus, dynamic compressive strength, and Dynamic Increase Factor (DIF) showed a strong correlation with the foam admixture and density. In addition, the incorporation of polypropylene (PP) fibers effectively improved the mechanical behavior of the foam concrete, achieving up to a 17% increase in dynamic compressive strength. This comprehensive analysis highlights the critical role of foam admixture and fiber reinforcement in determining the dynamic properties of CO<jats:sub>2</jats:sub>-cured foam concrete and provides valuable insights for optimizing the dynamic performance of foam concrete in various construction applications.","PeriodicalId":12524,"journal":{"name":"Frontiers in Materials","volume":"7 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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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