Pub Date : 2018-11-16DOI: 10.1201/9781351045636-140000337
B. Rivolta, R. Gerosa
The demand of alloys with high strength-to-density ratio is continuously increasing in the engineering world. Beside very expensive materials, such as the titanium alloys and the high strength reinforced polymers, the aluminum alloys represent an excellent alternative to satisfy the challenging requirements of many mechanical and aerospace applications. Among these alloys, the heat treatable grades are much appreciated for the possibility to increase the mechanical resistance significantly after solution treatment and aging. The former aims to create a supersaturated solution that is later modified during the latter by the formation of metastable precipitates involving all or some of the alloying elements. In the technical literature, it is well known that the corrosion resistance and the mechanical properties of these alloys, especially the 7xxx grades, strongly depend on the quenching conditions after the solution treatment. This phenomenon is known as “quench sensitivity.” The main aim of this entry is to discuss the influence of the cooling rate during quenching of different commercial aluminum alloys from mechanical and corrosion points of view. The influence of the rolling direction and of the alloy temper will be considered to focusing the attention on some experimental data obtained on the 7075 aluminum alloy.
{"title":"Quench Sensitivity of Aluminum Alloys","authors":"B. Rivolta, R. Gerosa","doi":"10.1201/9781351045636-140000337","DOIUrl":"https://doi.org/10.1201/9781351045636-140000337","url":null,"abstract":"The demand of alloys with high strength-to-density ratio is continuously increasing in the engineering world. Beside very expensive materials, such as the titanium alloys and the high strength reinforced polymers, the aluminum alloys represent an excellent alternative to satisfy the challenging requirements of many mechanical and aerospace applications. Among these alloys, the heat treatable grades are much appreciated for the possibility to increase the mechanical resistance significantly after solution treatment and aging. The former aims to create a supersaturated solution that is later modified during the latter by the formation of metastable precipitates involving all or some of the alloying elements. In the technical literature, it is well known that the corrosion resistance and the mechanical properties of these alloys, especially the 7xxx grades, strongly depend on the quenching conditions after the solution treatment. This phenomenon is known as “quench sensitivity.” The main aim of this entry is to discuss the influence of the cooling rate during quenching of different commercial aluminum alloys from mechanical and corrosion points of view. The influence of the rolling direction and of the alloy temper will be considered to focusing the attention on some experimental data obtained on the 7075 aluminum alloy.","PeriodicalId":348912,"journal":{"name":"Encyclopedia of Aluminum and Its Alloys","volume":"258 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125810063","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-11-16DOI: 10.1201/9781351045636-140000408
V. I. Lukin
Scandium in aluminum alloys behaves as the most efficient modifier of the structure of the material and as an agent suppressing recrystallization. This unique behavior of scandium in alloys of the Al-Mg system greatly increases the strength characteristics, whilst retaining on a higher level the ductility and processing properties of deformed semi-finished products. This article describes the effect of complex alloying the Al-6.3% Mg alloy with scandium, manganese and zirconium on the weldability and strength properties of the material is of considerable scientific and practical importance.Investigations.
{"title":"Weldability: Effect of Alloying Element Sc, Mn, and Zr on Alloys of the Al-Mg-Sc-Mn-Zr System","authors":"V. I. Lukin","doi":"10.1201/9781351045636-140000408","DOIUrl":"https://doi.org/10.1201/9781351045636-140000408","url":null,"abstract":"Scandium in aluminum alloys behaves as the most efficient modifier of the structure of the material and as an agent suppressing recrystallization. This unique behavior of scandium in alloys of the Al-Mg system greatly increases the strength characteristics, whilst retaining on a higher level the ductility and processing properties of deformed semi-finished products. This article describes the effect of complex alloying the Al-6.3% Mg alloy with scandium, manganese and zirconium on the weldability and strength properties of the material is of considerable scientific and practical importance.Investigations.","PeriodicalId":348912,"journal":{"name":"Encyclopedia of Aluminum and Its Alloys","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134629858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-11-16DOI: 10.1201/9781351045636-140000217
J. L. Á. Ambriz, Erasmo Correa Gomez, J. C. V. Juárez, Gonzalo M. Domínguez Almaraz, Aymeric E. Dominguez
This article deals with torsion fatigue tests carried out on the aluminum alloys: AISI 6061-T6 and 6063-T5, under two load ratios: R = −1 and R = 0, both of them at 10 Hz of frequency. The tests were obtained at room temperature (23°C) and with environmental humidity comprised between 35% and 45%. Results reveal a noticeable fatigue endurance reduction on tests with R = 0 against tests at R = −1 for both aluminum alloys. The load ratio was fixed by imposing the initial angle before the testing starting. A new torsion fatigue machine has been developed by two of the authors (under patent consideration before the Mexican Institute of Industrial Property), which has the versatility of torsion tests at different frequencies and load ratios; a general description of this machine is presented in the article. The torsion fatigue life and the fracture surfaces were analyzed for the two aluminum alloys and both torsion fatigue load ratios, leading to drawing up the conclusions related to this research article.
{"title":"Fatigue Endurance under Torsion Testing: 6061-T6 and 6063-T5 Aluminum Alloys","authors":"J. L. Á. Ambriz, Erasmo Correa Gomez, J. C. V. Juárez, Gonzalo M. Domínguez Almaraz, Aymeric E. Dominguez","doi":"10.1201/9781351045636-140000217","DOIUrl":"https://doi.org/10.1201/9781351045636-140000217","url":null,"abstract":"This article deals with torsion fatigue tests carried out on the aluminum alloys: AISI 6061-T6 and 6063-T5, under two load ratios: R = −1 and R = 0, both of them at 10 Hz of frequency. The tests were obtained at room temperature (23°C) and with environmental humidity comprised between 35% and 45%. Results reveal a noticeable fatigue endurance reduction on tests with R = 0 against tests at R = −1 for both aluminum alloys. The load ratio was fixed by imposing the initial angle before the testing starting. A new torsion fatigue machine has been developed by two of the authors (under patent consideration before the Mexican Institute of Industrial Property), which has the versatility of torsion tests at different frequencies and load ratios; a general description of this machine is presented in the article. The torsion fatigue life and the fracture surfaces were analyzed for the two aluminum alloys and both torsion fatigue load ratios, leading to drawing up the conclusions related to this research article.","PeriodicalId":348912,"journal":{"name":"Encyclopedia of Aluminum and Its Alloys","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134322036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-11-16DOI: 10.1201/9781351045636-140000243
S. Murty, Sushant K. Manwatkar, P. Narayanan
{"title":"Transmission Electron Micrographs of Aluminum Alloys","authors":"S. Murty, Sushant K. Manwatkar, P. Narayanan","doi":"10.1201/9781351045636-140000243","DOIUrl":"https://doi.org/10.1201/9781351045636-140000243","url":null,"abstract":"","PeriodicalId":348912,"journal":{"name":"Encyclopedia of Aluminum and Its Alloys","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129033336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-11-16DOI: 10.1201/9781351045636-140000417
Murat Tiryakio, J. Campbell
Guidelines for designing research on cast aluminium alloys have been developed to increase the reproducibility of results and make their interpretation more objective. These guidelines, based on the scientific method and recent research findings, are proposed for research on aluminium castings, but they can be easily adapted for other casting alloys.
{"title":"Metal Casting Research: Application to Aluminum Alloy Casting","authors":"Murat Tiryakio, J. Campbell","doi":"10.1201/9781351045636-140000417","DOIUrl":"https://doi.org/10.1201/9781351045636-140000417","url":null,"abstract":"Guidelines for designing research on cast aluminium alloys have been developed to increase the reproducibility of results and make their interpretation more objective. These guidelines, based on the scientific method and recent research findings, are proposed for research on aluminium castings, but they can be easily adapted for other casting alloys.","PeriodicalId":348912,"journal":{"name":"Encyclopedia of Aluminum and Its Alloys","volume":"163 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132013861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-11-16DOI: 10.1201/9781351045636-140000326
S. Bakhtiyarov, R. Overfelt
A rotational, contactless inductive measurement technique has been used to determine the effect of pores and metallic insertions on the electrical resistivity of A2011 aluminum alloy at different temperatures. It is shown that the electrical resistivity increases with the total volume of pores and is also dependent on the pores locations and orientation. Additional energy losses were found on the contact surfaces between sample and insertions.
{"title":"Molten Aluminum: Inductive Technique for Electrical Conductivity Measurements","authors":"S. Bakhtiyarov, R. Overfelt","doi":"10.1201/9781351045636-140000326","DOIUrl":"https://doi.org/10.1201/9781351045636-140000326","url":null,"abstract":"A rotational, contactless inductive measurement technique has been used to determine the effect of pores and metallic insertions on the electrical resistivity of A2011 aluminum alloy at different temperatures. It is shown that the electrical resistivity increases with the total volume of pores and is also dependent on the pores locations and orientation. Additional energy losses were found on the contact surfaces between sample and insertions.","PeriodicalId":348912,"journal":{"name":"Encyclopedia of Aluminum and Its Alloys","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129372470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-11-16DOI: 10.1201/9781351045636-140000445
C. Garcia-cordovilla, E. Louis
Microstructural characterization of aluminum alloys is typically performed by combining microscopy techniques with measurement of physical properties such as conductivity and hardness. Relatively recently calorimetric techniques have been used to complement the more traditional methodologies. This article will discuss: basic principles, instrumentation and experimental procedures, reaction kinetics, and general rules for interpreting DTA and DSC data. Heat treatable, non-heat treatable alloy and aluminum-based composite characterization are discussed.
{"title":"Thermal Analysis of Aluminum Alloys","authors":"C. Garcia-cordovilla, E. Louis","doi":"10.1201/9781351045636-140000445","DOIUrl":"https://doi.org/10.1201/9781351045636-140000445","url":null,"abstract":"Microstructural characterization of aluminum alloys is typically performed by combining microscopy techniques with measurement of physical properties such as conductivity and hardness. Relatively recently calorimetric techniques have been used to complement the more traditional methodologies. This article will discuss: basic principles, instrumentation and experimental procedures, reaction kinetics, and general rules for interpreting DTA and DSC data. Heat treatable, non-heat treatable alloy and aluminum-based composite characterization are discussed.","PeriodicalId":348912,"journal":{"name":"Encyclopedia of Aluminum and Its Alloys","volume":"49 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129820409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-11-16DOI: 10.1201/9781351045636-140000236
M. Cabibbo
This article presents two case studies referring to the severe plastic deformation applied to Al-Mg-Si alloys. In a first case study, an Al-Mg-Si alloy in a T6 temper is subjected to equal-channel angular pressing (ECAP), and all the microstructure strengthening contributions to the alloy yield stress are determined through specific modeling and then validated. In a second case study, two Al-Mg-Si alloys, one with Zr addition and a second with Sc-Zr addition, are subjected to ECAP after a T6 temper in an overaged status. In the second case, the role of the Zr- and Sc-Zr-containing nanometer dispersoids is described, and the related strengthening effect is modeled according to the models presented in the first case study.
{"title":"Al-Mg-Si: Microstructural Analysis","authors":"M. Cabibbo","doi":"10.1201/9781351045636-140000236","DOIUrl":"https://doi.org/10.1201/9781351045636-140000236","url":null,"abstract":"This article presents two case studies referring to the severe plastic deformation applied to Al-Mg-Si alloys. In a first case study, an Al-Mg-Si alloy in a T6 temper is subjected to equal-channel angular pressing (ECAP), and all the microstructure strengthening contributions to the alloy yield stress are determined through specific modeling and then validated. In a second case study, two Al-Mg-Si alloys, one with Zr addition and a second with Sc-Zr addition, are subjected to ECAP after a T6 temper in an overaged status. In the second case, the role of the Zr- and Sc-Zr-containing nanometer dispersoids is described, and the related strengthening effect is modeled according to the models presented in the first case study.","PeriodicalId":348912,"journal":{"name":"Encyclopedia of Aluminum and Its Alloys","volume":"576 2 Pt 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115849074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-11-16DOI: 10.1201/9781351045636-140000212
G. Mrówka‐Nowotnik
Analysis of the influence of chemical composition, crystallization process and heat treatment on the phase constituents’ morphology, and mechanical properties and crack resistance of 6xxx Al alloys were conducted. The alloys with low Mg and Si content (6063) in the as-cast state are characterized by presence of Si particles and primary intermetallic phases: α-Al8Fe2Si, β-Al5FeSi, β-Mg2Si, and α-Al(FeMn)Si. Higher Mg, Si, and Mn content (6005 and 6082) leads to separation of additional phase particles: Al6Fe, Al6Mn, and Al12(FeMn)Mg3Si6, whereas high Cu content (6061—0.35% and 6066—0.95%, respectively) is responsible for precipitation of additional phase particles: Q-Al5Cu2Mg8Si6 and θ-Al2Cu. It has been established that homogenization results in total dissolution of the θ-Al2Cu and Q-Al5Cu2Mg8Si6 primary phases and partial dissolution of β-Mg2Si. Needle-like and Chinese-script α-Al8Fe2Si and β-Al5FeSi were transformed into spheroidal α-Al(FeMn)Si particles. The maximal consolidation of the 6xxx alloys is a result of precipitation of metastable particles, the transient βʺ, βʹ, and Qʹ/θʹ phases (6061 alloy) with high dispersion. The highest mechanical properties were achieved after holding in the temperature of 565°C/6 h, supersaturated in water, and aging at 175°C/10–20 h (T6). The decohesion process in the presence of tensile stresses in the room temperature proceeds through nucleation, the growth and joining of the voids, as well as the cracking of the primary and secondary large-sized intermetallic phase particles. The increase of deformation temperature up to 300°C causes the changes of the nucleation source and joining of voids—it occurs mainly along the matrix–particle interface.
分析了化学成分、结晶工艺和热处理对6xxx铝合金相组分形貌、力学性能和抗裂性能的影响。铸态低Mg、低Si合金(6063)的主要特征是存在Si颗粒和初生金属间相:α-Al8Fe2Si、β-Al5FeSi、β-Mg2Si和α-Al(FeMn)Si。较高的Mg、Si和Mn含量(6005和6082)导致附加相颗粒Al6Fe、Al6Mn和Al12(FeMn)Mg3Si6的分离，而高的Cu含量(分别为6061-0.35%和6066-0.95%)导致附加相颗粒Q-Al5Cu2Mg8Si6和θ-Al2Cu的析出。结果表明，均质化导致θ-Al2Cu和Q-Al5Cu2Mg8Si6初相全部溶解，β-Mg2Si部分溶解。针状α-Al8Fe2Si和β-Al5FeSi转化为球状α-Al(FeMn)Si颗粒。6xxx合金的最大固结是亚稳颗粒的析出，即高弥散的瞬态β′、β′和Q′/θ′相(6061合金)。温度为565℃/6 h，在水中过饱和，175℃/ 10-20 h (T6)时效后，获得了最高的力学性能。在室温拉伸应力作用下的脱粘过程是通过成核、孔洞的生长和连接以及大尺寸金属间相颗粒的开裂进行的。变形温度升高至300℃时，引起了形核源的变化和孔洞的接合，主要发生在基体-颗粒界面。
{"title":"6XXX Alloys: Chemical Composition and Heat Treatment","authors":"G. Mrówka‐Nowotnik","doi":"10.1201/9781351045636-140000212","DOIUrl":"https://doi.org/10.1201/9781351045636-140000212","url":null,"abstract":"Analysis of the influence of chemical composition, crystallization process and heat treatment on the phase constituents’ morphology, and mechanical properties and crack resistance of 6xxx Al alloys were conducted. The alloys with low Mg and Si content (6063) in the as-cast state are characterized by presence of Si particles and primary intermetallic phases: α-Al8Fe2Si, β-Al5FeSi, β-Mg2Si, and α-Al(FeMn)Si. Higher Mg, Si, and Mn content (6005 and 6082) leads to separation of additional phase particles: Al6Fe, Al6Mn, and Al12(FeMn)Mg3Si6, whereas high Cu content (6061—0.35% and 6066—0.95%, respectively) is responsible for precipitation of additional phase particles: Q-Al5Cu2Mg8Si6 and θ-Al2Cu. It has been established that homogenization results in total dissolution of the θ-Al2Cu and Q-Al5Cu2Mg8Si6 primary phases and partial dissolution of β-Mg2Si. Needle-like and Chinese-script α-Al8Fe2Si and β-Al5FeSi were transformed into spheroidal α-Al(FeMn)Si particles. The maximal consolidation of the 6xxx alloys is a result of precipitation of metastable particles, the transient βʺ, βʹ, and Qʹ/θʹ phases (6061 alloy) with high dispersion. The highest mechanical properties were achieved after holding in the temperature of 565°C/6 h, supersaturated in water, and aging at 175°C/10–20 h (T6). The decohesion process in the presence of tensile stresses in the room temperature proceeds through nucleation, the growth and joining of the voids, as well as the cracking of the primary and secondary large-sized intermetallic phase particles. The increase of deformation temperature up to 300°C causes the changes of the nucleation source and joining of voids—it occurs mainly along the matrix–particle interface.","PeriodicalId":348912,"journal":{"name":"Encyclopedia of Aluminum and Its Alloys","volume":"107 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114490126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-11-16DOI: 10.1201/9781351045636-140000206
Hülya Demirören
In the present article, aluminum and its heat treatments were expressed. Also it was investigated that the influence of quenching type after solutizing heat treatment of cast Al-8.88Si-3.38 Cu on the microstructure has been reported. Alloys were prepared by controlled melting and casting. All the alloys were solutionized at 525°C for 4 h followed by water quenching at 65°C for 1, 15, 30, 60, and 90 min, respectively, and aged at 175°C for 4 h. Then they were cooled at room temperature. It was performed SEM–EDX analysis and X-ray analysis. From the analysis, it was determined Al2Cu and Al7FeCu2 phases. It was determined that those phases reinforce the microstructure. As a result, the type of quenching after solution treatment is very important for aluminum alloys.
{"title":"Microstructure of Aluminum Alloys: Effect of Hardening Conditions","authors":"Hülya Demirören","doi":"10.1201/9781351045636-140000206","DOIUrl":"https://doi.org/10.1201/9781351045636-140000206","url":null,"abstract":"In the present article, aluminum and its heat treatments were expressed. Also it was investigated that the influence of quenching type after solutizing heat treatment of cast Al-8.88Si-3.38 Cu on the microstructure has been reported. Alloys were prepared by controlled melting and casting. All the alloys were solutionized at 525°C for 4 h followed by water quenching at 65°C for 1, 15, 30, 60, and 90 min, respectively, and aged at 175°C for 4 h. Then they were cooled at room temperature. It was performed SEM–EDX analysis and X-ray analysis. From the analysis, it was determined Al2Cu and Al7FeCu2 phases. It was determined that those phases reinforce the microstructure. As a result, the type of quenching after solution treatment is very important for aluminum alloys.","PeriodicalId":348912,"journal":{"name":"Encyclopedia of Aluminum and Its Alloys","volume":"74 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120897112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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