Pub Date : 2024-08-30DOI: 10.1088/2053-1591/ad6f72
Gajesh G S Usgaonkar, Rajesh S Prabhu Gaonkar
The current work advocates the use of Cashew Nut Shell Liquid/Oil (CNSL), an oil extract of the leftover cashew nut shells, as a novel environment-friendly cutting fluid in sustainable machining operations. The tribological characteristics of CNSL obtained on a pin-on-disc tribometer are found to be better compared to the traditionally used cutting fluid. Experiments are conducted on the surface grinder with EN8 material, considering input parameters, such as cutting fluid type, grinder speed and grade, work speed, and depth of cut, with Surface Roughness (Ra) and Grinding Temperature (Temp) being the responses. Input parameter optimization is performed using Taguchi’s statistical models. A total of 36 investigative and six validation experiments are conducted, and a prediction model is proposed. When Ra and Temp are optimized simultaneously, the prediction value of Ra is 0.071 μm, and the corresponding value of Temp is 31.6 °C for which the experimental values are 0.072 μm and 32 °C respectively. This work also applies the TODIM (TOmada de Decisao Interativa Multicriterio, in the Portuguese language), a multi-attribute decision-making method for ranking the input parameter settings. The study reveals that the performance of CNSL is better than that of a traditional cutting fluid, and the TODIM method can be successfully applied to rank the input parameter settings.
{"title":"Optimization and ranking of the input parameter settings of sustainable grinding using cashew nut shell liquid as cutting fluid","authors":"Gajesh G S Usgaonkar, Rajesh S Prabhu Gaonkar","doi":"10.1088/2053-1591/ad6f72","DOIUrl":"https://doi.org/10.1088/2053-1591/ad6f72","url":null,"abstract":"The current work advocates the use of Cashew Nut Shell Liquid/Oil (CNSL), an oil extract of the leftover cashew nut shells, as a novel environment-friendly cutting fluid in sustainable machining operations. The tribological characteristics of CNSL obtained on a pin-on-disc tribometer are found to be better compared to the traditionally used cutting fluid. Experiments are conducted on the surface grinder with EN8 material, considering input parameters, such as cutting fluid type, grinder speed and grade, work speed, and depth of cut, with Surface Roughness (<italic toggle=\"yes\">Ra</italic>) and Grinding Temperature (<italic toggle=\"yes\">Temp</italic>) being the responses. Input parameter optimization is performed using Taguchi’s statistical models. A total of 36 investigative and six validation experiments are conducted, and a prediction model is proposed. When <italic toggle=\"yes\">Ra</italic> and <italic toggle=\"yes\">Temp</italic> are optimized simultaneously, the prediction value of <italic toggle=\"yes\">Ra</italic> is 0.071 μm, and the corresponding value of <italic toggle=\"yes\">Temp</italic> is 31.6 °C for which the experimental values are 0.072 μm and 32 °C respectively. This work also applies the TODIM (TOmada de Decisao Interativa Multicriterio, in the Portuguese language), a multi-attribute decision-making method for ranking the input parameter settings. The study reveals that the performance of CNSL is better than that of a traditional cutting fluid, and the TODIM method can be successfully applied to rank the input parameter settings.","PeriodicalId":18530,"journal":{"name":"Materials Research Express","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142181217","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 : 2024-08-30DOI: 10.1088/2053-1591/ad719e
Zhimin Liu, Kuijun Fu, Zhen Xu, Jiaji Wang, Ming Zhao, Dong Wang
To accurately replicate actual production and save production costs, this study examines the influence of the tempering process on the structure, mechanical properties, and corrosion resistance of E690 marine steel. Various techniques were employed to evaluate its properties, behavior, and performance, including metallurgical microscopy, scanning electron microscopy, transmission electron microscopy, electron backscatter diffraction, impact experiments, tensile tests, and electrochemical corrosion tests. The results indicate that as the tempering temperature increases, the tempering degree of the tempered martensite structure improves, the martensite strip coarsens, the size of the precipitated carbide increases, and the proportion of large-angle grain boundaries decreases. Consequently, the tensile strength and yield strength initially increase and then decrease, while the impact toughness and elongation gradually improve. At a tempering temperature of 600 °C, the steel exhibits the best overall mechanical properties, with a tensile strength of 729 MPa, yield strength of 649 MPa, and elongation of 18%. Furthermore, at a tempering temperature of 550 °C, the test steel shows an optimal corrosion resistance, with a corrosion rate of 0.03233 mm y−1 and an open-circuit potential of −0.36 V.
为了精确复制实际生产并节约生产成本，本研究探讨了回火工艺对 E690 船用钢的结构、机械性能和耐腐蚀性能的影响。研究采用了多种技术来评估其特性、行为和性能，包括金相显微镜、扫描电子显微镜、透射电子显微镜、电子反向散射衍射、冲击实验、拉伸试验和电化学腐蚀试验。结果表明，随着回火温度的升高，回火马氏体结构的回火程度提高，马氏体条粗化，析出的碳化物尺寸增大，大角度晶界比例降低。因此，抗拉强度和屈服强度先升高后降低，而冲击韧性和伸长率则逐渐提高。回火温度为 600 ℃ 时，钢的整体机械性能最佳，抗拉强度为 729 兆帕，屈服强度为 649 兆帕，伸长率为 18%。此外，在 550 °C 的回火温度下，试验钢材显示出最佳的耐腐蚀性，腐蚀速率为 0.03233 mm y-1，开路电位为 -0.36 V。
{"title":"Effect of tempering process on the mechanical properties and corrosion resistance of E690 marine steel","authors":"Zhimin Liu, Kuijun Fu, Zhen Xu, Jiaji Wang, Ming Zhao, Dong Wang","doi":"10.1088/2053-1591/ad719e","DOIUrl":"https://doi.org/10.1088/2053-1591/ad719e","url":null,"abstract":"To accurately replicate actual production and save production costs, this study examines the influence of the tempering process on the structure, mechanical properties, and corrosion resistance of E690 marine steel. Various techniques were employed to evaluate its properties, behavior, and performance, including metallurgical microscopy, scanning electron microscopy, transmission electron microscopy, electron backscatter diffraction, impact experiments, tensile tests, and electrochemical corrosion tests. The results indicate that as the tempering temperature increases, the tempering degree of the tempered martensite structure improves, the martensite strip coarsens, the size of the precipitated carbide increases, and the proportion of large-angle grain boundaries decreases. Consequently, the tensile strength and yield strength initially increase and then decrease, while the impact toughness and elongation gradually improve. At a tempering temperature of 600 °C, the steel exhibits the best overall mechanical properties, with a tensile strength of 729 MPa, yield strength of 649 MPa, and elongation of 18%. Furthermore, at a tempering temperature of 550 °C, the test steel shows an optimal corrosion resistance, with a corrosion rate of 0.03233 mm y<sup>−1</sup> and an open-circuit potential of −0.36 V.","PeriodicalId":18530,"journal":{"name":"Materials Research Express","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142223753","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}
The drive for more sustainable and environmentally friendly construction practices has resulted in revolutionary concrete production methods. One way is to include scrap rubber tires (contributing significantly to environmental pollution) into concrete mixtures to increase deformability. This study investigates the impact of surface-treated waste tire rubber (which partially replaces natural coarse aggregates with 5%, 10%, and 15% by weight) and industrial steel fiber (as reinforcement by including 0.5, 1, and 1.5% volume fractions) in concrete. Twelve concrete mixtures were prepared as test specimens. The replacement percentage was then determined using the compressive strength test results for additional surface treatment with three different alkaline solution (NaOH) concentrations (5%, 10%, and 15%) for 72 h. Thus, the hardened concrete properties were analyzed using compressive strength, flexural strength, and toughness; whereas the fresh qualities of equivalent concrete mixtures were evaluated using concrete slump. The findings revealed that, while partial replacement had a negative impact on the mechanical properties of the concrete, it was possible to produce rubberized concrete with better mechanical properties than conventional concrete when the partial replacement was less than 5%, treated with 10% alkaline solution, and reinforced with 1.5% steel fibers. The study’s findings illustrate the potential of these combinations for use in concrete pavement and slab applications.
{"title":"Synergistic effects of steel fiber and rubberized aggregates on concrete properties","authors":"Belay Bayu Tefera, Abrham Gebre Tarekegn, Tsagazeab Yimer Ejigu","doi":"10.1088/2053-1591/ad6f6f","DOIUrl":"https://doi.org/10.1088/2053-1591/ad6f6f","url":null,"abstract":"The drive for more sustainable and environmentally friendly construction practices has resulted in revolutionary concrete production methods. One way is to include scrap rubber tires (contributing significantly to environmental pollution) into concrete mixtures to increase deformability. This study investigates the impact of surface-treated waste tire rubber (which partially replaces natural coarse aggregates with 5%, 10%, and 15% by weight) and industrial steel fiber (as reinforcement by including 0.5, 1, and 1.5% volume fractions) in concrete. Twelve concrete mixtures were prepared as test specimens. The replacement percentage was then determined using the compressive strength test results for additional surface treatment with three different alkaline solution (NaOH) concentrations (5%, 10%, and 15%) for 72 h. Thus, the hardened concrete properties were analyzed using compressive strength, flexural strength, and toughness; whereas the fresh qualities of equivalent concrete mixtures were evaluated using concrete slump. The findings revealed that, while partial replacement had a negative impact on the mechanical properties of the concrete, it was possible to produce rubberized concrete with better mechanical properties than conventional concrete when the partial replacement was less than 5%, treated with 10% alkaline solution, and reinforced with 1.5% steel fibers. The study’s findings illustrate the potential of these combinations for use in concrete pavement and slab applications.","PeriodicalId":18530,"journal":{"name":"Materials Research Express","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142181218","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 : 2024-08-29DOI: 10.1088/2053-1591/ad7014
Aneel Manan, Pu Zhang, Wael Alattyih, Hani Alanazi, S K Elagan, Jawad Ahmad
The production of cement, which is the key ingredient of concrete, leads to environmental pollution by releasing massive amounts of CO2 and using significant natural resources. Therefore, shifting towards sustainable and greener materials is essential for mitigating these challenges. In this study, recycled concrete powder (RCP) was used as a cement replacement (0%, 5.0%, 10%, and 15%), solving the waste dumps issue and promoting sustainability. Furthermore, the concrete is also reinforced with steel fibers which were obtained from waste rubber tires to improve concrete tensile strength. The concrete properties were evaluated through slump cone test, compressive strength, failure patterns, tensile strength, scanning electronic microscopy, and FTIR analysis. The results indicate that the concrete strength properties improved with the substitution of RCP. The compressive and tensile strength of the optimum mix (10% RCP and 2.0% addition of steel fibers) are 15.8% and 23% more than those of reference concrete. However, the concrete flow is adversely impacted due to RCP angular particle shapes. Failure patterns indicate that RCP and steel fibers improved concrete ductility. SEM and FTIR analysis indicate microstructural improvement with RCP and steel fibers. Finally, the analysis concluded that the developed concrete showed better performance, solved waste dumps issues, and promoted sustainability.
{"title":"Mechanical and microstructural characterization of sustainable concrete containing recycled concrete and waste rubber tire fiber","authors":"Aneel Manan, Pu Zhang, Wael Alattyih, Hani Alanazi, S K Elagan, Jawad Ahmad","doi":"10.1088/2053-1591/ad7014","DOIUrl":"https://doi.org/10.1088/2053-1591/ad7014","url":null,"abstract":"The production of cement, which is the key ingredient of concrete, leads to environmental pollution by releasing massive amounts of CO<sub>2</sub> and using significant natural resources. Therefore, shifting towards sustainable and greener materials is essential for mitigating these challenges. In this study, recycled concrete powder (RCP) was used as a cement replacement (0%, 5.0%, 10%, and 15%), solving the waste dumps issue and promoting sustainability. Furthermore, the concrete is also reinforced with steel fibers which were obtained from waste rubber tires to improve concrete tensile strength. The concrete properties were evaluated through slump cone test, compressive strength, failure patterns, tensile strength, scanning electronic microscopy, and FTIR analysis. The results indicate that the concrete strength properties improved with the substitution of RCP. The compressive and tensile strength of the optimum mix (10% RCP and 2.0% addition of steel fibers) are 15.8% and 23% more than those of reference concrete. However, the concrete flow is adversely impacted due to RCP angular particle shapes. Failure patterns indicate that RCP and steel fibers improved concrete ductility. SEM and FTIR analysis indicate microstructural improvement with RCP and steel fibers. Finally, the analysis concluded that the developed concrete showed better performance, solved waste dumps issues, and promoted sustainability.","PeriodicalId":18530,"journal":{"name":"Materials Research Express","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142181235","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 : 2024-08-29DOI: 10.1088/2053-1591/ad71a0
Zhongyu DOU, Shupeng Luo, Dianxi Zhang
To enhance the performance of titanium plated coating on the surface of magnesium alloy AZ31, this study investigates the influence of N ion implantation dose on the structure, mechanical properties, and friction corrosion behavior of Ti film. The results reveal that N ion implantation leads to the formation of a new physical phase TiN and induces surface softening. However, with an increase in N ion implantation dose, microhardness of the Ti film increases due to the formation of TiN which enhances its hardness. Friction and wear experiments demonstrate that at maximum implantation dose, the coating exhibits minimal friction coefficient; however, an implantation dose of 5 × 1015 ion cm−2 offers superior wear resistance. The electrochemical test results indicate the corrosion current density and self-corrosion potential of Ti coating decrease with the increase of implantation dose due to the formation of nitride and the presence of N element, and corrosion resistance of the modified coating has been significantly enhanced. The research results provide reference for improving the protection performance of Ti coating on magnesium alloy surface.
为了提高镁合金 AZ31 表面镀钛涂层的性能，本研究探讨了 N 离子注入剂量对钛膜结构、机械性能和摩擦腐蚀行为的影响。结果表明，N 离子植入会导致形成新的物理相 TiN 并引起表面软化。然而，随着 N 离子注入剂量的增加，Ti 膜的显微硬度会增加，这是由于 TiN 的形成提高了其硬度。摩擦和磨损实验表明，在最大植入剂量下，涂层的摩擦系数最小；然而，植入剂量为 5 × 1015 离子 cm-2 时，耐磨性更优。电化学测试结果表明，由于氮化物的形成和 N 元素的存在，Ti 涂层的腐蚀电流密度和自腐蚀电位随植入剂量的增加而降低，改性涂层的耐腐蚀性能显著增强。研究结果为提高镁合金表面 Ti 涂层的防护性能提供了参考。
{"title":"The effect of ion implantation dose on the friction and corrosion performance of titanium-coated magnesium alloy","authors":"Zhongyu DOU, Shupeng Luo, Dianxi Zhang","doi":"10.1088/2053-1591/ad71a0","DOIUrl":"https://doi.org/10.1088/2053-1591/ad71a0","url":null,"abstract":"To enhance the performance of titanium plated coating on the surface of magnesium alloy AZ31, this study investigates the influence of N ion implantation dose on the structure, mechanical properties, and friction corrosion behavior of Ti film. The results reveal that N ion implantation leads to the formation of a new physical phase TiN and induces surface softening. However, with an increase in N ion implantation dose, microhardness of the Ti film increases due to the formation of TiN which enhances its hardness. Friction and wear experiments demonstrate that at maximum implantation dose, the coating exhibits minimal friction coefficient; however, an implantation dose of 5 × 10<sup>15</sup> ion cm<sup>−2</sup> offers superior wear resistance. The electrochemical test results indicate the corrosion current density and self-corrosion potential of Ti coating decrease with the increase of implantation dose due to the formation of nitride and the presence of N element, and corrosion resistance of the modified coating has been significantly enhanced. The research results provide reference for improving the protection performance of Ti coating on magnesium alloy surface.","PeriodicalId":18530,"journal":{"name":"Materials Research Express","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142181239","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 : 2024-08-29DOI: 10.1088/2053-1591/ad6ff8
Nhung Thi Tran
We have developed a novel, eco-friendly, and active food packaging film by incorporating green-synthesized silver nanoparticles (AgNPs) into polyvinyl alcohol (PVA) and chitosan matrices. The AgNPs were in situ and green synthesized in high-yield by using Aloe vera extract as a reducing agent and chitosan as a stabilizing agent at high temperature. The obtained AgNPs exhibit quasi-spherical shapes and tunable size in the range 20 ∼ 30 nm by controlling the content of AgNO3 precursor in the growth solution. The in situ synthesis enables the homogeneous distribution of AgNPs throughout the films and eliminates the need for purification. The effect of the loaded amounts of Aloe vera-synthesized AgNPs on the film characteristics was investigated. The results show that the obtained AgNPs-loaded films exhibit excellent mechanical properties (tensile strength of 36.7 MPa and elongation at break of 213.9%) and superior bacterial killing and inhibition effects against E. coli. Moreover, the incorporation of green-synthesized AgNPs into the polymeric films also results in a significant improvement in the contact angles formed between the film surface and glycerol droplets, enhanced thermal stability, and a reduction in water swelling and water solubility. All these results highlight the great potential of these biodegradable and antibacterial membranes as an alternative to petroleum-based plastics in food packaging and preservation.
{"title":"Aloe vera-synthesized Ag nanoparticles loaded on PVA/chitosan as biodegradable and antibacterial film for food storage","authors":"Nhung Thi Tran","doi":"10.1088/2053-1591/ad6ff8","DOIUrl":"https://doi.org/10.1088/2053-1591/ad6ff8","url":null,"abstract":"We have developed a novel, eco-friendly, and active food packaging film by incorporating green-synthesized silver nanoparticles (AgNPs) into polyvinyl alcohol (PVA) and chitosan matrices. The AgNPs were <italic toggle=\"yes\">in situ</italic> and green synthesized in high-yield by using <italic toggle=\"yes\">Aloe vera</italic> extract as a reducing agent and chitosan as a stabilizing agent at high temperature. The obtained AgNPs exhibit quasi-spherical shapes and tunable size in the range 20 ∼ 30 nm by controlling the content of AgNO<sub>3</sub> precursor in the growth solution. The <italic toggle=\"yes\">in situ</italic> synthesis enables the homogeneous distribution of AgNPs throughout the films and eliminates the need for purification. The effect of the loaded amounts of <italic toggle=\"yes\">Aloe vera</italic>-synthesized AgNPs on the film characteristics was investigated. The results show that the obtained AgNPs-loaded films exhibit excellent mechanical properties (tensile strength of 36.7 MPa and elongation at break of 213.9%) and superior bacterial killing and inhibition effects against <italic toggle=\"yes\">E. coli</italic>. Moreover, the incorporation of green-synthesized AgNPs into the polymeric films also results in a significant improvement in the contact angles formed between the film surface and glycerol droplets, enhanced thermal stability, and a reduction in water swelling and water solubility. All these results highlight the great potential of these biodegradable and antibacterial membranes as an alternative to petroleum-based plastics in food packaging and preservation.","PeriodicalId":18530,"journal":{"name":"Materials Research Express","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142181236","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 : 2024-08-29DOI: 10.1088/2053-1591/ad6ff7
Ilanthalir Amala Sornam, Jerlin Regin Joseph Dominic
The current study aimed to use coconut shell concrete, a structural lightweight concrete, as an infill material in concrete-filled steel tube (CFST) columns and test it under axial compression. Testing was done on eighteen short, intermediate and long coconut shell CFST columns and six normal-weight CFST short columns for comparison. For both types of columns, the axial load-displacement curves and modes of failure were examined. By varying the length-to-diameter and diameter-to-thickness ratios, the axial capacity of steel tubes filled with coconut shell concrete was assessed. The composite action was verified from the results of the confinement index, strength index and the contribution of the coconut shell concrete as infill concrete. Structural efficiency and energy absorption of the lightweight CFST column was contrasted with its counterpart column. The contribution of coconut shell concrete to the strength of the CFST column was the highest at 61.36% and more significant than that of normal-weight CFST columns. The coconut shell CFST columns were 23.63% lighter than the normal-weight columns, contributing to its higher structural efficiency. These columns also had 8.12% more energy absorption than normal-weight columns. Hence, the results of this investigation revealed that coconut shell concrete has the potential to be utilized in CFST columns. Further, compared to the experimental ultimate loads, the predictions made by the existing codes, EC4 and ANSI/AISC 360 are conservative.
{"title":"Performance of lightweight coconut shell concrete-filled circular steel tube columns under axial compression","authors":"Ilanthalir Amala Sornam, Jerlin Regin Joseph Dominic","doi":"10.1088/2053-1591/ad6ff7","DOIUrl":"https://doi.org/10.1088/2053-1591/ad6ff7","url":null,"abstract":"The current study aimed to use coconut shell concrete, a structural lightweight concrete, as an infill material in concrete-filled steel tube (CFST) columns and test it under axial compression. Testing was done on eighteen short, intermediate and long coconut shell CFST columns and six normal-weight CFST short columns for comparison. For both types of columns, the axial load-displacement curves and modes of failure were examined. By varying the length-to-diameter and diameter-to-thickness ratios, the axial capacity of steel tubes filled with coconut shell concrete was assessed. The composite action was verified from the results of the confinement index, strength index and the contribution of the coconut shell concrete as infill concrete. Structural efficiency and energy absorption of the lightweight CFST column was contrasted with its counterpart column. The contribution of coconut shell concrete to the strength of the CFST column was the highest at 61.36% and more significant than that of normal-weight CFST columns. The coconut shell CFST columns were 23.63% lighter than the normal-weight columns, contributing to its higher structural efficiency. These columns also had 8.12% more energy absorption than normal-weight columns. Hence, the results of this investigation revealed that coconut shell concrete has the potential to be utilized in CFST columns. Further, compared to the experimental ultimate loads, the predictions made by the existing codes, EC4 and ANSI/AISC 360 are conservative.","PeriodicalId":18530,"journal":{"name":"Materials Research Express","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142181233","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 : 2024-08-29DOI: 10.1088/2053-1591/ad719b
Chun Fu, Qiushi Zhang
With the depletion of natural resources and the requirement of higher strength-weight ratio, lightweight aggregate concrete has attracted more and more attention because of its good thermal properties, fire resistance and seismic performance. However, exposure to low temperature environments accelerates deterioration of concrete, thereby, reduce the service life of lightweight aggregate concrete. Even worse, in cold and arid regions, lightweight aggregate concrete often experiences accidental impacts, wind erosion, earthquakes, and other disasters during service, these damage significantly impact its frost-resistance. Therefore, accurately and quantitatively describing and predicting the frost-resistance of lightweight aggregate concrete under specific disaster conditions is crucial. In this study, take the initial damage degree and freeze-thaw cycles as input variables, while the relative dynamic elastic modulus (RDEM) as an out variable, a frost resistance prediction models for stress-damaged lightweight aggregate concrete was established based on back propagation neural network (BPNN). The results show that the predicted values of BPNN model are in good agreement with the experimental values, and the results are also compared with the revised Loland model which is proposed by another author. Results demonstrate that the average relative error between predicted values of BPNN and experimental values is only 1.69%, whereas the one of revised Loland model is 9.13%, which indicating that the proposed BPNN prediction model can achieve a relatively accurate quantitative assessment of frost-resistance throughout the entire post-disaster lifecycle of lightweight aggregate concrete, it also broadened the idea and provided a reference for the frost resistance prediction of stress-damaged lightweight aggregate concrete.
{"title":"Frost-resistance prediction model for stress-damaged lightweight aggregate concrete based on BPNN: a comparative study","authors":"Chun Fu, Qiushi Zhang","doi":"10.1088/2053-1591/ad719b","DOIUrl":"https://doi.org/10.1088/2053-1591/ad719b","url":null,"abstract":"With the depletion of natural resources and the requirement of higher strength-weight ratio, lightweight aggregate concrete has attracted more and more attention because of its good thermal properties, fire resistance and seismic performance. However, exposure to low temperature environments accelerates deterioration of concrete, thereby, reduce the service life of lightweight aggregate concrete. Even worse, in cold and arid regions, lightweight aggregate concrete often experiences accidental impacts, wind erosion, earthquakes, and other disasters during service, these damage significantly impact its frost-resistance. Therefore, accurately and quantitatively describing and predicting the frost-resistance of lightweight aggregate concrete under specific disaster conditions is crucial. In this study, take the initial damage degree and freeze-thaw cycles as input variables, while the relative dynamic elastic modulus (RDEM) as an out variable, a frost resistance prediction models for stress-damaged lightweight aggregate concrete was established based on back propagation neural network (BPNN). The results show that the predicted values of BPNN model are in good agreement with the experimental values, and the results are also compared with the revised Loland model which is proposed by another author. Results demonstrate that the average relative error between predicted values of BPNN and experimental values is only 1.69%, whereas the one of revised Loland model is 9.13%, which indicating that the proposed BPNN prediction model can achieve a relatively accurate quantitative assessment of frost-resistance throughout the entire post-disaster lifecycle of lightweight aggregate concrete, it also broadened the idea and provided a reference for the frost resistance prediction of stress-damaged lightweight aggregate concrete.","PeriodicalId":18530,"journal":{"name":"Materials Research Express","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142181237","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 : 2024-08-29DOI: 10.1088/2053-1591/ad719c
Ahmet Fatih Yayla, Ridvan Gecu, Nuri Solak, Kursat Kazmanli, Mustafa Urgen
This study investigated residual stress evaluations during gaseous nitriding of 50CrMo4 and 31CrMoV9 steels. The nitriding processes were carried out in the NH3/H2/N2 atmosphere at 525 °C for 2 h by controlling the nitriding potential. The development of depth-dependent residual stresses was conducted using a Vickers indentation instrument with an estimated geometric correction. The obtained results correlated with the sublayer removal-assisted XRD sin2ψ method. Diffusion layers between 135 and 200 μm were obtained for all samples upon nitriding. The surface hardness values reached 475 HV for 50CrMo4 and 825 HV for 31CrMoV9 steels. The geometric correction factor α was calculated as 78° for a Vickers indenter to measure residual stresses. The generated compressive residual stresses by nitriding increased with increasing nitriding potential by 71% (from −350 to −600 MPa) and 13% (from −750 to −850 MPa) for 50CrMo4 and 31CrMoV9 steels, respectively. An approximately linear relationship was obtained between the hardness and residual stress profiles of the nitrided samples.
{"title":"Measuring depth-dependent residual stresses in gaseous nitrided steels using indentation method","authors":"Ahmet Fatih Yayla, Ridvan Gecu, Nuri Solak, Kursat Kazmanli, Mustafa Urgen","doi":"10.1088/2053-1591/ad719c","DOIUrl":"https://doi.org/10.1088/2053-1591/ad719c","url":null,"abstract":"This study investigated residual stress evaluations during gaseous nitriding of 50CrMo4 and 31CrMoV9 steels. The nitriding processes were carried out in the NH<sub>3</sub>/H<sub>2</sub>/N<sub>2</sub> atmosphere at 525 °C for 2 h by controlling the nitriding potential. The development of depth-dependent residual stresses was conducted using a Vickers indentation instrument with an estimated geometric correction. The obtained results correlated with the sublayer removal-assisted XRD sin<sup>2</sup>ψ method. Diffusion layers between 135 and 200 μm were obtained for all samples upon nitriding. The surface hardness values reached 475 HV for 50CrMo4 and 825 HV for 31CrMoV9 steels. The geometric correction factor <italic toggle=\"yes\">α</italic> was calculated as 78° for a Vickers indenter to measure residual stresses. The generated compressive residual stresses by nitriding increased with increasing nitriding potential by 71% (from −350 to −600 MPa) and 13% (from −750 to −850 MPa) for 50CrMo4 and 31CrMoV9 steels, respectively. An approximately linear relationship was obtained between the hardness and residual stress profiles of the nitrided samples.","PeriodicalId":18530,"journal":{"name":"Materials Research Express","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142181238","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 : 2024-08-29DOI: 10.1088/2053-1591/ad71a3
Wei Cao, Chong Ma, Yang Li, Lei Gao, Guo Chen, Mamdouh Omran
Titanium and titanium alloys are key basic support materials in the field of engineering technology and high technology, and are widely used in the fields of natural gas transportation, chemical corrosion, and marine development. Titanium alloy ingots are often prepared with more solidification defects such as surface cracks and cold shuts, resulting in lower utilization of titanium metal and higher cost of titanium products. The root of this is the lack of in-depth knowledge of the ingot melting and casting process, and the failure to control the thermal conditions of the billet in the molding process within a reasonable range. In this study, based on the Lagrange Euler algorithm, combined with ProCAST finite element software to establish a numerical model, revealing the solid–liquid interface morphology, the length of the transition region, and the change rule of thermal stress under the influence of different process parameters in the solidification process of titanium slab ingot. The results show that with the increase in pulling speed, the depth of the solid–liquid phase line and the width of the mushy zone of slab ingot increase, and the length of the transition region grows. With the increase in casting temperature, the depth of the solid–liquid phase line of the slab ingot decreases, and the mushy zone gradually becomes narrower. The casting temperature and pulling speed are positively correlated with the value of the thermal stress equivalent stress in slab ingots, and the probability of cracks in the corners and ingot surface is higher. This study provides effective theoretical guidance for the realization of stable mass production of high-quality titanium slab ingot.
{"title":"Numerical simulation study on solidification proceoss of titanium slab ingot by electron beam cold hearth melting","authors":"Wei Cao, Chong Ma, Yang Li, Lei Gao, Guo Chen, Mamdouh Omran","doi":"10.1088/2053-1591/ad71a3","DOIUrl":"https://doi.org/10.1088/2053-1591/ad71a3","url":null,"abstract":"Titanium and titanium alloys are key basic support materials in the field of engineering technology and high technology, and are widely used in the fields of natural gas transportation, chemical corrosion, and marine development. Titanium alloy ingots are often prepared with more solidification defects such as surface cracks and cold shuts, resulting in lower utilization of titanium metal and higher cost of titanium products. The root of this is the lack of in-depth knowledge of the ingot melting and casting process, and the failure to control the thermal conditions of the billet in the molding process within a reasonable range. In this study, based on the Lagrange Euler algorithm, combined with ProCAST finite element software to establish a numerical model, revealing the solid–liquid interface morphology, the length of the transition region, and the change rule of thermal stress under the influence of different process parameters in the solidification process of titanium slab ingot. The results show that with the increase in pulling speed, the depth of the solid–liquid phase line and the width of the mushy zone of slab ingot increase, and the length of the transition region grows. With the increase in casting temperature, the depth of the solid–liquid phase line of the slab ingot decreases, and the mushy zone gradually becomes narrower. The casting temperature and pulling speed are positively correlated with the value of the thermal stress equivalent stress in slab ingots, and the probability of cracks in the corners and ingot surface is higher. This study provides effective theoretical guidance for the realization of stable mass production of high-quality titanium slab ingot.","PeriodicalId":18530,"journal":{"name":"Materials Research Express","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142181241","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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