Zr-Si-N thin films were co-deposited by reactive magnetron sputtering to verify the influence of silicon content (1.6 and 8.0 at. % Si) and substrate temperature (room temperature and heated to 973 K) on structure, morphology, chemical bonds and hardness. GAXRD shows a change in grain orientation from (111) to (200) due substrate heating for sample Zr 0.984 Si 0.016 N, furthermore, it was not possible to identify any silicon compounds in all deposited samples. SEM-FEG images show greater roughness and surface clusters for sample Zr 0.920 Si 0.080 N due to the heat applied on the substrate, with Si 3 N 4 decomposition, influencing thin film hardness. XPS analyses of Si 2p photoelectronic region shows only Si 3 N 4 presence in all samples, proving, in conjunction with other characterization results, the non-formation of substitutional or interstitial solid solution, regardless of substrate heating or silicon content added to ZrN matrix.
{"title":"Influence of Substrate Temperature on Microstructure of Zirconium Silicon Nitride Thin Films Deposited by Reactive Magnetron Sputtering","authors":"F.S. Oliveira, I.L. Dias, P.L.L. Araújo, D.A. Ramirez, P.C. Silva Neto, R. Hübler, F.M.T. Mendes, I.Z. Damasceno, E.K. Tentardini","doi":"10.1590/1980-5373-mr-2023-0235","DOIUrl":"https://doi.org/10.1590/1980-5373-mr-2023-0235","url":null,"abstract":"Zr-Si-N thin films were co-deposited by reactive magnetron sputtering to verify the influence of silicon content (1.6 and 8.0 at. % Si) and substrate temperature (room temperature and heated to 973 K) on structure, morphology, chemical bonds and hardness. GAXRD shows a change in grain orientation from (111) to (200) due substrate heating for sample Zr 0.984 Si 0.016 N, furthermore, it was not possible to identify any silicon compounds in all deposited samples. SEM-FEG images show greater roughness and surface clusters for sample Zr 0.920 Si 0.080 N due to the heat applied on the substrate, with Si 3 N 4 decomposition, influencing thin film hardness. XPS analyses of Si 2p photoelectronic region shows only Si 3 N 4 presence in all samples, proving, in conjunction with other characterization results, the non-formation of substitutional or interstitial solid solution, regardless of substrate heating or silicon content added to ZrN matrix.","PeriodicalId":18331,"journal":{"name":"Materials Research-ibero-american Journal of Materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135317462","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 : 2023-09-04DOI: 10.1590/1980-5373-mr-2023-0176
Sai Chand Kundurti, Ambuj Sharma
The structural performance of metallic components is a significant challenge especially when it comes to operating conditions in real-world applications. Friction stir additive manufacturing (FSAM) is a solid-state additive manufacturing (AM) that provides controlled microstructure with homogenous grains and excellent structural performance. In this study, the FSAM technique was utilized to fabricate a lightweight laminated AA6061/AA7075 metal matrix composite with improved mechanical properties. The feasibility of the FSAM was demonstrated to build multi-functional, multi-material components for aerospace, automotive, and defence industries to enable lightweight, high-strength components. The FSAM tool was designed with an optimum shoulder length, shoulder diameter, pin length, and pin diameter considering the plate thickness. Afterward, optimized process parameters were designed using the Taguchi L9 orthogonal array (OA) technique. Microstructural features and their effect on mechanical properties such as microhardness and ultimate tensile strength (UTS) were evaluated in the FSAM build. FSAM build improved in microhardness (from 107±1.2 to 138.4 ±2.8 HV 0.2 ) and tensile strength (from 310 to 384 MPa) as compared to base material AA6061. Corrosion resistance was also studied to understand the feasibility of the FSAM technique in various environmental conditions. The overall performance of the FSAM build shows promising results compared to the base materials.
{"title":"Evaluation of Microstructural, Mechanical and Corrosion Behaviours of Laminated AA6061/AA7075 Metal Matrix Composites Build by Friction Stir Additive Manufacturing for Structural Applications","authors":"Sai Chand Kundurti, Ambuj Sharma","doi":"10.1590/1980-5373-mr-2023-0176","DOIUrl":"https://doi.org/10.1590/1980-5373-mr-2023-0176","url":null,"abstract":"The structural performance of metallic components is a significant challenge especially when it comes to operating conditions in real-world applications. Friction stir additive manufacturing (FSAM) is a solid-state additive manufacturing (AM) that provides controlled microstructure with homogenous grains and excellent structural performance. In this study, the FSAM technique was utilized to fabricate a lightweight laminated AA6061/AA7075 metal matrix composite with improved mechanical properties. The feasibility of the FSAM was demonstrated to build multi-functional, multi-material components for aerospace, automotive, and defence industries to enable lightweight, high-strength components. The FSAM tool was designed with an optimum shoulder length, shoulder diameter, pin length, and pin diameter considering the plate thickness. Afterward, optimized process parameters were designed using the Taguchi L9 orthogonal array (OA) technique. Microstructural features and their effect on mechanical properties such as microhardness and ultimate tensile strength (UTS) were evaluated in the FSAM build. FSAM build improved in microhardness (from 107±1.2 to 138.4 ±2.8 HV 0.2 ) and tensile strength (from 310 to 384 MPa) as compared to base material AA6061. Corrosion resistance was also studied to understand the feasibility of the FSAM technique in various environmental conditions. The overall performance of the FSAM build shows promising results compared to the base materials.","PeriodicalId":18331,"journal":{"name":"Materials Research-ibero-american Journal of Materials","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2023-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67304950","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 : 2023-09-01DOI: 10.1590/1980-5373-mr-2023-0118
J.A.P. Carrasco, J.S. Junior, J.M.A. Barbosa, E.O. Vilar, M.A. dos Santos, A.A. Silva
Hydrogen permeation tests and tensile mechanical tests were performed at room temperature on API 5CT P110 steel to characterize hydrogen trapping and to evaluate their hydrogen embrittlement susceptibility. The hydrogen trap density was calculated from two consecutive hydrogen permeation transients plotted using an electrochemical cell. Slow strain rate tensile tests on hydrogen-charged samples through cathodic polarization at different potentials were performed to evaluate the hydrogen embrittlement susceptibility. Thereby it was established the lowest potential that characterizes the onset of the cathodic overprotection for studied steel. After mechanical tests was observed a decrease in ductility as the protection potential became more negative and that the fracture mode was changed from ductile microvoid coalescence on the as-received steel to extended quasi-cleavage on the hydrogen-charged steel. The results showed that API 5CT P110 steel has high susceptibility to hydrogen embrittlement conditioned by a predominance of reversible traps in microstructure and by high hydrogen solubility.
{"title":"Experimental Characterization of Hydrogen Trapping on API 5CT P110 Steel. Part. I: Effect on Hydrogen Embrittlement Susceptibility","authors":"J.A.P. Carrasco, J.S. Junior, J.M.A. Barbosa, E.O. Vilar, M.A. dos Santos, A.A. Silva","doi":"10.1590/1980-5373-mr-2023-0118","DOIUrl":"https://doi.org/10.1590/1980-5373-mr-2023-0118","url":null,"abstract":"Hydrogen permeation tests and tensile mechanical tests were performed at room temperature on API 5CT P110 steel to characterize hydrogen trapping and to evaluate their hydrogen embrittlement susceptibility. The hydrogen trap density was calculated from two consecutive hydrogen permeation transients plotted using an electrochemical cell. Slow strain rate tensile tests on hydrogen-charged samples through cathodic polarization at different potentials were performed to evaluate the hydrogen embrittlement susceptibility. Thereby it was established the lowest potential that characterizes the onset of the cathodic overprotection for studied steel. After mechanical tests was observed a decrease in ductility as the protection potential became more negative and that the fracture mode was changed from ductile microvoid coalescence on the as-received steel to extended quasi-cleavage on the hydrogen-charged steel. The results showed that API 5CT P110 steel has high susceptibility to hydrogen embrittlement conditioned by a predominance of reversible traps in microstructure and by high hydrogen solubility.","PeriodicalId":18331,"journal":{"name":"Materials Research-ibero-american Journal of Materials","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67305168","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 : 2023-09-01DOI: 10.1590/1980-5373-mr-2023-0108
E. Sakthivelmurugan, G. Senthil kumar, S.M. Vinu Kumar
,
{"title":"Effect of Alkali Treatment of Alstonia macrophylla (AS) fiber on Dynamic Mechanical and Machinability Properties of Polypropylene (PP) Composites reinforced with Unidirectional AS fiber","authors":"E. Sakthivelmurugan, G. Senthil kumar, S.M. Vinu Kumar","doi":"10.1590/1980-5373-mr-2023-0108","DOIUrl":"https://doi.org/10.1590/1980-5373-mr-2023-0108","url":null,"abstract":",","PeriodicalId":18331,"journal":{"name":"Materials Research-ibero-american Journal of Materials","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67304559","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}
{"title":"Development of Al-Based Nanocomposites Using CNT-GnP-hBN Ternary Hybrid Reinforcement","authors":"Arka Ghosh, Sourav Ganguly, Nasimul Alam Syed","doi":"10.1590/1980-5373-mr-2023-0241","DOIUrl":"https://doi.org/10.1590/1980-5373-mr-2023-0241","url":null,"abstract":",","PeriodicalId":18331,"journal":{"name":"Materials Research-ibero-american Journal of Materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136366845","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 : 2023-08-25DOI: 10.1590/1980-5373-mr-2023-0119
M. Serenario, B. Santos, R. C. Souza, J. R. Oliveira, G. L. Vaz, J. Gomes, A. Bueno
Flow is central to the operation of wells and pipelines and can be postulated to govern the formation of protective corrosion product layers, which is critical to overall infrastructure integrity. However, the phenomena involved remain poorly understood. Therefore, the main objective of this work was to investigate the effect of flow on the heterogeneous precipitation of FeS and FeCO 3 as corrosion products on mild steel. Initial corrosion studies were conducted in an autoclave stirred by an impeller. The tests were conducted under quiescent and dynamic conditions for 24 h in an aqueous brine (10 wt.% NaCl, 120°C, 5 bar CO 2 , 0 and 10 -3 mol/l Na 2 S 2 O 3 ). The experimental results showed that the increase in rotation speed did not prevent the formation of FeS or FeCO 3 crystals. Having confirmed the presence of corrosion product layers, the differences in the trends in corrosion rates may result from the diffusion barrier presented by these layers.
{"title":"Impact of Flow on the Development of Iron Sulfide and Iron Carbonate Layers","authors":"M. Serenario, B. Santos, R. C. Souza, J. R. Oliveira, G. L. Vaz, J. Gomes, A. Bueno","doi":"10.1590/1980-5373-mr-2023-0119","DOIUrl":"https://doi.org/10.1590/1980-5373-mr-2023-0119","url":null,"abstract":"Flow is central to the operation of wells and pipelines and can be postulated to govern the formation of protective corrosion product layers, which is critical to overall infrastructure integrity. However, the phenomena involved remain poorly understood. Therefore, the main objective of this work was to investigate the effect of flow on the heterogeneous precipitation of FeS and FeCO 3 as corrosion products on mild steel. Initial corrosion studies were conducted in an autoclave stirred by an impeller. The tests were conducted under quiescent and dynamic conditions for 24 h in an aqueous brine (10 wt.% NaCl, 120°C, 5 bar CO 2 , 0 and 10 -3 mol/l Na 2 S 2 O 3 ). The experimental results showed that the increase in rotation speed did not prevent the formation of FeS or FeCO 3 crystals. Having confirmed the presence of corrosion product layers, the differences in the trends in corrosion rates may result from the diffusion barrier presented by these layers.","PeriodicalId":18331,"journal":{"name":"Materials Research-ibero-american Journal of Materials","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67305195","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 : 2023-08-25DOI: 10.1590/1980-5373-mr-2022-0623
L. F. Lima, M. S. Libório, J. F. Medeiros Neto, K. S. Coan, L. S. Rossino, R. Sousa, M. G. C. B. Barbosa, R. M. Nascimento, M. Feitor, T. Costa
The use of thin films as solid lubricating makes it an excellent option for controlling wear and friction under certain operating conditions, in addition to not harming the environment. Thus, this work aims to study plasma deposition with a cathodic cage of MoS 2 thin films on AISI 1020 steel substrates. From the adaptation of the cathode Cage named cathode cylinders, the samples were treated in cathodic and floating potential with temperatures of 300 °C, 350 °C, and 400 °C in an argon atmosphere. After the treatments, they were subjected to chemical analysis by X-ray diffraction (XRD) and Raman spectroscopy, in addition to a calotest tribological test. Also, it was possible to quantify the coating thickness using scanning electron microscopy (SEM). In general, the results indicated success in the deposition of molybdenum disulfide in all samples treated at fluctuating potential, as it is possible to visualize in the XRD since it indicated the presence of peaks referring to MoS 2 and its compounds, in addition to an expressive reduction in wear through the calotest test.
{"title":"Plasma Deposition of Solid Lubricant Coating Using AISI1020 Steel Cathode Cylinders Technique","authors":"L. F. Lima, M. S. Libório, J. F. Medeiros Neto, K. S. Coan, L. S. Rossino, R. Sousa, M. G. C. B. Barbosa, R. M. Nascimento, M. Feitor, T. Costa","doi":"10.1590/1980-5373-mr-2022-0623","DOIUrl":"https://doi.org/10.1590/1980-5373-mr-2022-0623","url":null,"abstract":"The use of thin films as solid lubricating makes it an excellent option for controlling wear and friction under certain operating conditions, in addition to not harming the environment. Thus, this work aims to study plasma deposition with a cathodic cage of MoS 2 thin films on AISI 1020 steel substrates. From the adaptation of the cathode Cage named cathode cylinders, the samples were treated in cathodic and floating potential with temperatures of 300 °C, 350 °C, and 400 °C in an argon atmosphere. After the treatments, they were subjected to chemical analysis by X-ray diffraction (XRD) and Raman spectroscopy, in addition to a calotest tribological test. Also, it was possible to quantify the coating thickness using scanning electron microscopy (SEM). In general, the results indicated success in the deposition of molybdenum disulfide in all samples treated at fluctuating potential, as it is possible to visualize in the XRD since it indicated the presence of peaks referring to MoS 2 and its compounds, in addition to an expressive reduction in wear through the calotest test.","PeriodicalId":18331,"journal":{"name":"Materials Research-ibero-american Journal of Materials","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67304154","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 : 2023-08-25DOI: 10.1590/1980-5373-mr-2023-0239
M. G. Zimmermann, Marina Kauling de Almeira, Lara Vasconcellos Ponsoni, Majorie Anacleto Bernardo, A. J. Zattera, L. V. Beltrami, M. Poletto, Daiane Romanzini, Kristian Madeira
In this study, the effects of incorporating recycled photopolymer-plate residues from a packaging flexography process into polyester-glass fiber composites were examined. Ternary composites with an unsaturated polyester matrix with elastomer particles from recycled photopolymer-plate residues were evaluated using two types of glass fibers: in the forms of a fabric with bidirectional fibers and a blanket with multidirectional fibers. The composites were prepared by hand lay-up lamination using different rubber contents (0, 2.5, 5, and 10 wt% based on the polyester resin mass fraction), and were characterized for their void content, flexural and impact strengths, and dynamic mechanical properties. Primary results indicated that the incorporation of the rubber particles increased the difficulty of lamination, while promoting greater void formation with higher filler content. The rubber particles decreased the impact resistance properties but did not reduce the flexural strength or storage modulus, indicating that despite the elastomeric composition, this residue from the photopolymer plates showed a reinforcing rather than toughening character.
{"title":"Influence of Flexographic Photopolymer-Plate Residue Incorporation on the Mechanical Properties of Glass-Fiber-Reinforced Polyester Composites","authors":"M. G. Zimmermann, Marina Kauling de Almeira, Lara Vasconcellos Ponsoni, Majorie Anacleto Bernardo, A. J. Zattera, L. V. Beltrami, M. Poletto, Daiane Romanzini, Kristian Madeira","doi":"10.1590/1980-5373-mr-2023-0239","DOIUrl":"https://doi.org/10.1590/1980-5373-mr-2023-0239","url":null,"abstract":"In this study, the effects of incorporating recycled photopolymer-plate residues from a packaging flexography process into polyester-glass fiber composites were examined. Ternary composites with an unsaturated polyester matrix with elastomer particles from recycled photopolymer-plate residues were evaluated using two types of glass fibers: in the forms of a fabric with bidirectional fibers and a blanket with multidirectional fibers. The composites were prepared by hand lay-up lamination using different rubber contents (0, 2.5, 5, and 10 wt% based on the polyester resin mass fraction), and were characterized for their void content, flexural and impact strengths, and dynamic mechanical properties. Primary results indicated that the incorporation of the rubber particles increased the difficulty of lamination, while promoting greater void formation with higher filler content. The rubber particles decreased the impact resistance properties but did not reduce the flexural strength or storage modulus, indicating that despite the elastomeric composition, this residue from the photopolymer plates showed a reinforcing rather than toughening character.","PeriodicalId":18331,"journal":{"name":"Materials Research-ibero-american Journal of Materials","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67305010","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 : 2023-08-14DOI: 10.1590/1980-5373-mr-2023-0017
P.R.C. Silva, M. Colosio, M. Orlando, J. Rossi
Automotive industry is searching for new ways to improve vehicles’ energy efficiency through mass reduction, using aluminum alloys. This change requires a surface protection to extend the life cycle of the components and aluminum anodization is the most used solution. This research is focused on the intake and exhaust ducts’ surfaces of aluminum internal combustion engines cylinder head, which are subject to chemical agents and temperature variation. To extend the working life of this component it is necessary to obtain a covering protective layer. The process targeted the anodization of an internal surface of a much larger part of a cast aluminum-silicon alloy cylinder head. The anodization was obtained using a H 2 SO 4 solution (184 g.L -1 ) and a DC voltage starting at 20 V. The Al 2 O 3 layer obtained, inside the cylinder head´s ducts, has an average thickness of 120 µm in accordance with the proposal of providing a suitable surface protection.
{"title":"Obtention of Hard Coating Using Electrochemical Process in Aluminum-Silicon Alloys for Automotive Vehicles","authors":"P.R.C. Silva, M. Colosio, M. Orlando, J. Rossi","doi":"10.1590/1980-5373-mr-2023-0017","DOIUrl":"https://doi.org/10.1590/1980-5373-mr-2023-0017","url":null,"abstract":"Automotive industry is searching for new ways to improve vehicles’ energy efficiency through mass reduction, using aluminum alloys. This change requires a surface protection to extend the life cycle of the components and aluminum anodization is the most used solution. This research is focused on the intake and exhaust ducts’ surfaces of aluminum internal combustion engines cylinder head, which are subject to chemical agents and temperature variation. To extend the working life of this component it is necessary to obtain a covering protective layer. The process targeted the anodization of an internal surface of a much larger part of a cast aluminum-silicon alloy cylinder head. The anodization was obtained using a H 2 SO 4 solution (184 g.L -1 ) and a DC voltage starting at 20 V. The Al 2 O 3 layer obtained, inside the cylinder head´s ducts, has an average thickness of 120 µm in accordance with the proposal of providing a suitable surface protection.","PeriodicalId":18331,"journal":{"name":"Materials Research-ibero-american Journal of Materials","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2023-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67304271","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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