Journal of Materials Engineering and Performance最新文献

Effects of Retrogression and Re-aging (RRA) Processes on Corrosion Properties in AA 7020 Aluminium Alloy 回火和再时效 (RRA) 工艺对 AA 7020 铝合金腐蚀特性的影响

IF 2.2 4区材料科学

Journal of Materials Engineering and Performance Pub Date : 2024-09-30 DOI: 10.1007/s11665-024-10166-6

Mustafa Safa Yilmaz

{"title":"Effects of Retrogression and Re-aging (RRA) Processes on Corrosion Properties in AA 7020 Aluminium Alloy","authors":"Mustafa Safa Yilmaz","doi":"10.1007/s11665-024-10166-6","DOIUrl":"10.1007/s11665-024-10166-6","url":null,"abstract":"<div>AA 7020 alloy, widely used in the aviation and automobile industries with its specific strength, has become a material in demand in recent years by different sectors. Heat treatment to T6 temper increases the mechanical strength by precipitating hardening (ageing). Overaging to T73 temper improves the corrosion behavior of the alloy. A RRA (retrogression and re-ageing) heat treatment is a good alternative as it improves the corrosion behaviour compared to T6 temper and provides better mechanical values than precipitates from a material in T6 temper are redissolved by a short-term heat treatment between 160 and 280 °C (retrogression) which is then followed by a re-ageing under T6 heat treatment condition.In this study, the AA7020 alloy was retrogressed for 1, 5, 15, 30, and 45 minutes at 180, 200, and 240 °C. Before, it was re-ageing at 120 °C for 24 hours. The hardness, conductivity, and corrosion behaviour of the heat-treated samples were determined, and the microstructure was evaluated by light microscopy, scanning electron microscope (SEM), and Energy-dispersive x-ray spectroscopy (EDX) methods.</div>","PeriodicalId":644,"journal":{"name":"Journal of Materials Engineering and Performance","volume":"33 20","pages":"11231 - 11239"},"PeriodicalIF":2.2,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142565992","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}

引用次数: 0

Synergistic Effect of Ex Situ and In Situ Reinforcements on the Dry Reciprocating Wear Behavior of AA6061-B4C Composite Fabricated Using Varying K2TiF6 Flux Content 原位加固和原位加固对使用不同 K2TiF6 助熔剂含量制造的 AA6061-B4C 复合材料干式往复磨损行为的协同效应

IF 2.3 4区材料科学

Journal of Materials Engineering and Performance Pub Date : 2024-09-19 DOI: 10.1007/s11665-024-10106-4

Chandan Kumar, Indrani Sen, Siddhartha Roy

{"title":"Synergistic Effect of Ex Situ and In Situ Reinforcements on the Dry Reciprocating Wear Behavior of AA6061-B4C Composite Fabricated Using Varying K2TiF6 Flux Content","authors":"Chandan Kumar, Indrani Sen, Siddhartha Roy","doi":"10.1007/s11665-024-10106-4","DOIUrl":"https://doi.org/10.1007/s11665-024-10106-4","url":null,"abstract":"This study aims to examine the dry reciprocating wear behavior of stir–squeeze cast AA6061-B4C composites under the synergistic effect of ex situ B4C particles and in situ formed Al-Ti intermetallic phases due to the use of K2TiF6 salt as flux and Mg2Si precipitates formed after T6 heat treatment process. The K2TiF6 flux content in the composites varied between 40 and 100% of a constant B4C content (6 wt.%). The heat treatment consisted of solutionizing at 540 °C for 8 h, followed by water quenching and then artificially aging at 180 °C for 4 h. While at any applied load, the wear rate decreased with increasing ex situ B4C particle retention, at applied loads more than 20 N, the wear performance deteriorated due to increased fracture and dislodgement of B4C particles. In situ Al-Ti intermetallics were more effective in lowering the wear rate at high applied loads. A mechanically mixed layer (MML) consisting of self-lubricating boron oxide and boric acid was formed in composites with high B4C particle retention, lowering the friction coefficient up to 20 N applied load. However, the friction coefficient increased at a higher applied load of 30 N due to increased peeling off the MML and three-body wear.","PeriodicalId":644,"journal":{"name":"Journal of Materials Engineering and Performance","volume":"187 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142253633","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}

引用次数: 0

Effects of Ga Content on Microstructure Evolution and Mechanical Response of Heterostructured Dual-Phase Ag-49Cu Alloys 镓含量对异质结构双相银-49铜合金微结构演变和机械响应的影响

IF 2.3 4区材料科学

Journal of Materials Engineering and Performance Pub Date : 2024-09-19 DOI: 10.1007/s11665-024-10118-0

Haipeng Yang, Yudong Sui, Yehua Jiang, Zhilong Tan, Xingyu Wang, Hao Zhou

{"title":"Effects of Ga Content on Microstructure Evolution and Mechanical Response of Heterostructured Dual-Phase Ag-49Cu Alloys","authors":"Haipeng Yang, Yudong Sui, Yehua Jiang, Zhilong Tan, Xingyu Wang, Hao Zhou","doi":"10.1007/s11665-024-10118-0","DOIUrl":"https://doi.org/10.1007/s11665-024-10118-0","url":null,"abstract":"Dual-phase heterostructured metals have excellent mechanical properties. This study systematically evaluated the impact of varying Ga concentrations on the microstructural evolution and mechanical response of dual-phase heterostructured Ag-49 wt.%Cu-xGa (x = 0, 5, 7, and 10 wt.%) alloys. The study utilized scanning electron microscopy (SEM) and nanoindentation experiments to analyze the structure evolution and hardness changes in Ag-Cu-Ga alloys. The results revealed that the volume fraction of the hard domains (Cu-rich phases) and the hardness increased as the Ga content increased. This increase in Ga content led to a greater degree of mechanical incompatibility between the soft and hard domains, ultimately enhancing the mechanical properties of Ag-Cu-Ga alloys. Through the implementation of a loading–unloading–reloading (LUR) test, it was shown that the Ag-49Cu-7Ga specimens exhibited higher levels of hetero-deformation-induced (HDI) stresses compared to the Ag-49Cu specimens that did not contain Ga elements. This difference can be attributed to the solid solution strengthening effect of Ga. Through the use of digital imaging technique (DIC), it has been discovered that the introduction of Ga element into the Ag-Cu-Ga specimen results in the formation of dispersed strain bands on the surface. These strain bands effectively absorb and distribute the applied strains, resulting in the Ag-49Cu-7Ga specimen exhibiting both high strength and good plasticity.","PeriodicalId":644,"journal":{"name":"Journal of Materials Engineering and Performance","volume":"9 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142253634","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}

引用次数: 0

The Effect of Cryogenic Treatment on Microstructure and Properties of WC–Co Cemented Carbides 低温处理对 WC-Co 硬质合金显微结构和性能的影响

IF 2.3 4区材料科学

Journal of Materials Engineering and Performance Pub Date : 2024-09-19 DOI: 10.1007/s11665-024-10087-4

Yuan Gao, Yongguo Wang, Zhi Chen

{"title":"The Effect of Cryogenic Treatment on Microstructure and Properties of WC–Co Cemented Carbides","authors":"Yuan Gao, Yongguo Wang, Zhi Chen","doi":"10.1007/s11665-024-10087-4","DOIUrl":"https://doi.org/10.1007/s11665-024-10087-4","url":null,"abstract":"ISO coded K06 cemented carbides are gradually becoming a commonly used tool materials for machining difficult-to-machine materials such as superalloy due to their excellent cutting performance. Researchers are exploring advanced manufacturing processes that can further enhance the performance of this material. Therefore, the cryogenic treatment of ISO coded K06 WC–Co cemented carbide was studied by uniform design experiment. The equation of the effect of cryogenic treatment on the properties of cemented carbide was fitted by multivariate quadratic nonlinear regression. The phase composition, grain size, and residual stress of the material were analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results indicate that cryogenic treatment significantly changes the residual stress of WC grains, accompanied by a phase transition of the bonding phase (Co phase). However, cryogenic treatment has no significant effect on the grain size of the material. The wear resistance and impact toughness of cemented carbide have been significantly improved. At the same time, the wear scar and impact fracture of the material were observed, and the mechanism of impact fracture was analyzed. The residual compressive stress of the WC phase increased by about 120% and the rockwell hardness of the material increased by about 2.61% after cryogenic treatment, but the increase was insignificant. However, the wear resistance increased by about 88.89% and the impact toughness increased by about 19.30%.","PeriodicalId":644,"journal":{"name":"Journal of Materials Engineering and Performance","volume":"2 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142253637","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}

引用次数: 0

Effect of Deep Cryogenic Treatment on the Mechanical Properties and Defect Tolerance of Selective-Laser-Melted 316L Stainless Steel 深冷处理对选择性激光熔化 316L 不锈钢机械性能和缺陷容忍度的影响

IF 2.3 4区材料科学

Journal of Materials Engineering and Performance Pub Date : 2024-09-19 DOI: 10.1007/s11665-024-10110-8

Feng Feng, Bing Yang, Tao Zhu, Shoune Xiao, Guangwu Yang, Mingmeng Wang, Dongdong Chen

{"title":"Effect of Deep Cryogenic Treatment on the Mechanical Properties and Defect Tolerance of Selective-Laser-Melted 316L Stainless Steel","authors":"Feng Feng, Bing Yang, Tao Zhu, Shoune Xiao, Guangwu Yang, Mingmeng Wang, Dongdong Chen","doi":"10.1007/s11665-024-10110-8","DOIUrl":"https://doi.org/10.1007/s11665-024-10110-8","url":null,"abstract":"In this study, the effects of deep cryogenic treatment on the microstructure and mechanical properties of 316L stainless steel fabricated by selective laser melting were investigated. Two types of samples were subjected to comparative experiments: (i) as printed (AP), and (ii) deep cryogenic treatment (DCT). Microstructural analysis revealed that DCT reduced the sample porosity from 1.05 to 0.36%. In terms of mechanical properties, the DCT samples exhibited tensile and yield strengths of 736 MPa and 541 MPa, respectively, which are significantly higher than those of conventionally cast parts. The elongation reached 59%, a crucial factor for applications requiring material flexibility. However, fatigue test results showed a reduction in the fatigue performance of DCT samples. The fatigue limit was predicted using extreme value statistical analysis and sample sectioning methods, with the prediction error within 10%. The Kitagawa–Takahashi diagram and EI-Haddad model were used to evaluate the safety performance of the material, and the critical defect sizes of the samples were determined. The prediction results were consistent with the statistical analysis of crack source defect sizes in fractured samples.","PeriodicalId":644,"journal":{"name":"Journal of Materials Engineering and Performance","volume":"39 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142253635","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}

引用次数: 0

Investigation of Ti2AlNb-Added TiAl Composite Prepared by Direct Laser Deposition 研究通过直接激光沉积法制备的 Ti2AlNb 添加 TiAl 复合材料

IF 2.3 4区材料科学

Journal of Materials Engineering and Performance Pub Date : 2024-09-19 DOI: 10.1007/s11665-024-10078-5

Guohui Zhang, Renyao Qin, Neng Li, Zhiqi Qu, Tianyuan Wang, Biao Zhou

{"title":"Investigation of Ti2AlNb-Added TiAl Composite Prepared by Direct Laser Deposition","authors":"Guohui Zhang, Renyao Qin, Neng Li, Zhiqi Qu, Tianyuan Wang, Biao Zhou","doi":"10.1007/s11665-024-10078-5","DOIUrl":"https://doi.org/10.1007/s11665-024-10078-5","url":null,"abstract":"Ti2AlNb/TiAl composite columnar specimens without defects were fabricated by using direct laser deposition (DLD) process. In this study, the microstructure and mechanical properties were comprehensively investigated. Results revealed that each deposited layer contains two microstructure bands: the equiaxed grain band and the lamellar colony band. These two bands appeared as γ/α2 lamellar with random lath orientation under high magnification, with different lamellar spacing of 210 and 380 μm, respectively. Unmelted Ti2AlNb particles could be found in the lamellar colony band, which could decrease the dislocation density further to increase the strength. The tensile strength at room temperature reaches 541-543 MPa, with a corresponding elongation of 0.6-0.8%, while the fracture occurs mainly in the equiaxed grain bands with a translocation fracture mechanism. Hardness tests also showed higher hardness values in the lamellar colony bands than in the equiaxial grain bands. CT characterization tests did not reveal that fracture cracks started or passed through the Ti2AlNb grains. These results demonstrate an in-depth understanding of the microstructure and properties of Ti2AlNb/TiAl composites prepared by DLD, and provide a pioneering reference for further investigations of the strengthening effect of Ti2AlNb on TiAl-based alloys.","PeriodicalId":644,"journal":{"name":"Journal of Materials Engineering and Performance","volume":"6 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142268816","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}

引用次数: 0

Mechanical and Metallurgical Properties of Foam Developed by Friction Stir Tube Deposition Technique 用搅拌摩擦管沉积技术制备的泡沫的机械和冶金性能

IF 2.3 4区材料科学

Journal of Materials Engineering and Performance Pub Date : 2024-09-19 DOI: 10.1007/s11665-024-09961-y

Mandeep Kumar, Ratnesh Kumar Raj Singh, Vivek Jain

引用次数: 0

Microstructures and Mechanical Properties of 12Cr12Mo Martensitic Stainless Steel Manufactured by Selective Laser Melting 选择性激光熔融法制造的 12Cr12Mo 马氏体不锈钢的微观结构和力学性能

IF 2.3 4区材料科学

Journal of Materials Engineering and Performance Pub Date : 2024-09-18 DOI: 10.1007/s11665-024-10075-8

Runqi Yang, Linzhi Wang, Yikai Xiong, Chenyu Liao, Ting Li

{"title":"Microstructures and Mechanical Properties of 12Cr12Mo Martensitic Stainless Steel Manufactured by Selective Laser Melting","authors":"Runqi Yang, Linzhi Wang, Yikai Xiong, Chenyu Liao, Ting Li","doi":"10.1007/s11665-024-10075-8","DOIUrl":"https://doi.org/10.1007/s11665-024-10075-8","url":null,"abstract":"In this study, 12Cr12Mo martensitic stainless steel was manufactured using selective laser melting (SLM). The resulting microstructures and mechanical properties were analyzed under optimal process parameters to understand the correlation between the process, microstructure, and properties. The results showed that only a single martensitic phase is present in the SLM samples, attributed to the exceptionally rapid solidification rate and high density of dislocations. It was observed that the 12Cr12Mo microstructure consists of interspersed columnar and equiaxed grains at the microscale, while fine body-centered cubic (bcc) lath martensite with high dislocation density is observed at the submicron scale. SLM-prepared 12Cr12Mo stainless steel exhibits impressive mechanical properties due to its hierarchical microstructure. Under optimal process parameters, the fabricated samples achieved a microhardness of 544.91 HV, with yield and ultimate tensile strengths of 729 ± 24 and 842 ± 19 MPa, respectively, but elongation is limited to 7 ± 0.6%. The cellular and martensitic structures with high dislocation density along grain boundaries are the mean factor for the increased strength but reduced ductility. Observations of a disintegrated surface and river-like patterns suggest a brittle fracture mode in 12Cr12Mo stainless steel prepared by SLM.","PeriodicalId":644,"journal":{"name":"Journal of Materials Engineering and Performance","volume":"32 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142253641","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}

引用次数: 0

Enhancement of High-Temperature Mechanical Properties in Al-Si-Cu-Ni-Mg Alloy by Micro-nano TiC Particle Complex Clusters 微纳米 TiC 粒子复合团簇增强铝硅铜镍镁合金的高温力学性能

IF 2.3 4区材料科学

Journal of Materials Engineering and Performance Pub Date : 2024-09-18 DOI: 10.1007/s11665-024-10105-5

Sunhang Xiao, Zhengbing Xiao, Jinchuan Wen, Zhijie Dai, Dahong Zhao

{"title":"Enhancement of High-Temperature Mechanical Properties in Al-Si-Cu-Ni-Mg Alloy by Micro-nano TiC Particle Complex Clusters","authors":"Sunhang Xiao, Zhengbing Xiao, Jinchuan Wen, Zhijie Dai, Dahong Zhao","doi":"10.1007/s11665-024-10105-5","DOIUrl":"https://doi.org/10.1007/s11665-024-10105-5","url":null,"abstract":"This study aims to elucidate the influence of varying TiC particle additions on the mechanical properties of Al-10Si-3.5Cu-2.5Ni-0.3Mg alloys. The alloys were fabricated using the gravity casting technique, with TiC additions of 0, 0.5, 0.75, and 1%. Following T6 heat treatment, the microstructure, tensile strength, and fracture mechanisms of the alloys were comprehensively analyzed. The research findings indicate that the microstructure is primarily composed of α-Al, eutectic Si, Al3Ni, Al3CuNi, (Al, Si)2(Zr, Ti), and (Al, Si)3(Zr, Ti) phases. Image J quantitative analysis indicated that increasing TiC content resulted in the refinement of both the eutectic silicon and the grains. Additionally, the Al3Ni and Al3CuNi phases gradually became spheroidized and had a homogeneous distribution. The 350 °C tensile strength of the alloy increased from 93.7 to 137.8 Mpa with increasing TiC content, an increase of 44.1 MPa (47%). This is mainly attributed to the stability of the (Al, Si)2(Zr, Ti) phases at high temperatures and the refinement of the grains, eutectic silicon, and intermetallic second phases.","PeriodicalId":644,"journal":{"name":"Journal of Materials Engineering and Performance","volume":"64 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142253640","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}

引用次数: 0

Experimental Studies on Microscopic and Mechanical Properties of Nimonic 90 Superalloy Synthesized Using Powder Metallurgy 利用粉末冶金法合成的镍铬 90 超合金的微观和力学性能实验研究

IF 2.3 4区材料科学

Journal of Materials Engineering and Performance Pub Date : 2024-09-18 DOI: 10.1007/s11665-024-10093-6

Geetika K. Salwan, Rayapati Subbarao, Subrata Mondal

{"title":"Experimental Studies on Microscopic and Mechanical Properties of Nimonic 90 Superalloy Synthesized Using Powder Metallurgy","authors":"Geetika K. Salwan, Rayapati Subbarao, Subrata Mondal","doi":"10.1007/s11665-024-10093-6","DOIUrl":"https://doi.org/10.1007/s11665-024-10093-6","url":null,"abstract":"Application of nickel-based superalloys is gradually rising in many sectors such as aerospace, automotive and marine industries due to their exceptional thermo-mechanical properties. Superalloys are predominantly fabricated by casting process. The pursuit of customized materials possessing with exceptional properties has driven the scholars to investigate the possibility of powder metallurgy for preparing them and assess their appropriateness to produce gas turbine components. This study focuses on the use of powder metallurgy approach for synthesizing Nimonic 90 superalloy. Physical properties such as density, microhardness and macrohardness are determined to validate with the standard sample. Mechanical properties like tensile strength and compressive strength are measured and analyzed. Dry sliding wear test is done to study the wear characteristics. Density and hardness of the material are close to that of standard alloy, which is due to the appropriate selection of sintering temperature and stay time. Measured values for the ultimate tensile strength, 0.2% offset yield strength and percentage of elongation are approximately 900 MPa, 386 MPa and 52%, respectively. In microscopic study, it is observed that the material has γ/γ’ phase because of precipitation hardening and solid solution strengthening. Findings establish the fundamental basis for near-net-shape manufacturing by powder metallurgy.","PeriodicalId":644,"journal":{"name":"Journal of Materials Engineering and Performance","volume":"77 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142268937","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}

引用次数: 0