International Journal of Plasticity最新文献

{"title":"Achieving superior strength-ductility balance by tailoring dislocation density and shearable GP zone of extruded Al-Cu-Li alloy","authors":"Xuanxi Xu ,&nbsp;Guohua Wu ,&nbsp;Xin Tong ,&nbsp;Liang Zhang ,&nbsp;Cunlong Wang ,&nbsp;Fangzhou Qi ,&nbsp;Xiaopeng Zeng ,&nbsp;Youjie Guo","doi":"10.1016/j.ijplas.2024.104135","DOIUrl":"10.1016/j.ijplas.2024.104135","url":null,"abstract":"<div><div>Pre-stretching is commonly employed to accelerate ageing precipitation kinetics in wrought Al-Cu-Li alloys, but uneven precipitation resulting from dislocation pile-ups often degrades ductility. Herein, the strength and ductility of extruded Al-Cu-Li alloy are significantly improved through a novel thermomechanical treatment, involving pre-ageing and pre-stretching, followed by low-temperature interrupted ageing. A superior balance between high yield strength (∼ 657 MPa) and good ductility (elongation to fracture of ∼ 13.5 %) is obtained, with elongation increased by 105 % compared to the conventional T8 temper, while maintaining a respectable yield strength. Microstructure analysis reveals that dense Guinier–Preston (GP) zones induced by pre-ageing effectively dissipate energy from dislocation sliding, resulting in a uniform dislocation configuration even at 8 % pre-stretching. However, the GP zone density is greatly reduced due to their dissolution following pre-stretching. Upon interrupted ageing, the reprecipitation of GP zones forms a homogeneous mixture of δ′, GP zones, and T₁ phases. This combination alleviates local stress concentrations and lengthens the dislocation mean free path during tensile testing by shearing the GP zones at multiple sites, thereby improving ductility. Simultaneously, T₁ precipitates strengthen the alloy by pinning dislocations and promoting dislocation cross-slip, improving work hardening capacity. The dissolution of GP zones also redistributes the Cu atoms within the matrix, further enhancing the intrinsic ductility of the Al matrix. These findings offer valuable insights for developing high-performance wrought Al-Cu-Li alloys.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"182 ","pages":"Article 104135"},"PeriodicalIF":9.4,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142306436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Crack-tip cleavage/dislocation emission competition behaviors/mechanisms in magnesium: ALEFM prediction and atomic simulation","authors":"Jia-ping Ma ,&nbsp;Lin Yuan ,&nbsp;Ying-ying Zong ,&nbsp;Ming-yi Zheng ,&nbsp;De-bin Shan ,&nbsp;Bin Guo","doi":"10.1016/j.ijplas.2024.104134","DOIUrl":"10.1016/j.ijplas.2024.104134","url":null,"abstract":"<div><div>Structural properties and reliability of materials can be improved by increasing fracture toughness. At the atomic scale, the fracture is a material separation process, and the fracture toughness of materials is associated with the atomic-scale crack-tip behaviors/mechanisms. The crack-tip behaviors are relevant to the energy state of atoms in the system. Atomic thermal oscillation increases with increasing temperature, which may affect/alter the crack tip behaviors. This work is the first to investigate the temperature-dependent crack-tip cleavage/dislocation emitting competition in magnesium (Mg) using anisotropic linear elastic fracture mechanics theory, Density Functional Theory (DFT), and atomic simulation. Crack-tip behaviors are examined using a specially designed ‘K-field’ loads model. DFT calculations show that a single crystal system with lower entropy and higher Gibbs free energy implies stronger interatomic bonding that favors a higher <em>K_Ic</em>. Changes in the stress distribution initiate a brittle-ductile transition in crack-tip behavior. The ductile crack tip can be blunted by continuous crack-tip dislocations nucleation/slip, and the evolution of the ductile crack-tip geometry from sharp to semicircular structure significantly decreases the stress concentration at the crack tip. A new criterion of the crack-tip force vector is established, which reasonably explains the geometrical evolution of ductile crack tip where the angle <span><math><mi>θ</mi></math></span> between the crack plane and the slip plane is <span><math><mrow><msup><mn>0</mn><mo>∘</mo></msup><mo>&lt;</mo><mi>θ</mi><mo>&lt;</mo><msup><mn>90</mn><mo>∘</mo></msup></mrow></math></span> and <span><math><mrow><mi>θ</mi><mrow></mrow><mo>=</mo><msup><mn>90</mn><mo>∘</mo></msup></mrow></math></span>. This work expands the atomic-scale brittle/ductile crack-tip behaviors/mechanisms of Mg, which provides a reference for crack-tip behavior analysis in engineering research.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"182 ","pages":"Article 104134"},"PeriodicalIF":9.4,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142306450","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dislocation accumulation-induced strength-ductility synergy in TRIP-aided duplex stainless steel","authors":"Jianquan Wan ,&nbsp;Binbin He ,&nbsp;Xusheng Yang ,&nbsp;LingBing Kong ,&nbsp;Xiaowei Zuo ,&nbsp;Zengbao Jiao","doi":"10.1016/j.ijplas.2024.104130","DOIUrl":"10.1016/j.ijplas.2024.104130","url":null,"abstract":"<div><p>In this study, we investigate the intrinsic mechanism of intensive and progressive transformation-induced plasticity (TRIP) effects and their different strength-ductility synergies using a resource-efficient 15Cr-2Ni duplex stainless steel. The progressive TRIP material exhibits a ductility that is more than twice that of the intensive TRIP material, as well as, a larger product of the ultimate tensile strength and ductility. This is attributed to the dislocation accumulation caused by different grain sizes of strain-induced martensite depending on the stability of the <em>γ</em> phase, which determines the strength and work hardening of steel. When the stability is low, the <em>γ</em> phase is sensitive to loaded stress and transformed into dispersed fine martensite immediately after yielding at a high rate. It induces a sigmoid-shaped dislocation accumulation to an approximately 10-fold increase in the dislocation density at a limited strain, resulting in intensive work hardening and a large ultimate tensile strength. As the stability is adequate, the <em>γ</em> phase is transformed into coarse martensite laths with a high critical load stress, which is initiated from a delayed strain at an extremely low rate and steadily accelerated as the strain increases. This process induces a gradually increased dislocation accumulation to a 2–3-fold increase in the dislocation density at large strains, resulting in progressive work hardening and an excellent ductility.</p></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"182 ","pages":"Article 104130"},"PeriodicalIF":9.4,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142235219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of grain size on the deformation mechanism and fracture behavior of a non-equiatomic CoCrNi alloy with low stacking fault energy","authors":"S.Y. Peng ,&nbsp;Y.Z. Tian ,&nbsp;Z.Y. Ni ,&nbsp;S. Lu ,&nbsp;S. Li","doi":"10.1016/j.ijplas.2024.104129","DOIUrl":"10.1016/j.ijplas.2024.104129","url":null,"abstract":"<div><p>Manipulation of stacking fault energy (SFE) plays a significant role in microstructure control and in turn mechanical properties of advanced alloys. In this work, we present the influence of grain size on the mechanical properties and fracture behavior of a non-equiatomic CoCrNi alloy with low SFE. Specimens with controlled grain sizes ranging from 0.61 to 6.4 µm were fabricated through rolling and annealing. A novel SFs-dominated plastic deformation mechanism was discovered. Tensile strength decreases monotonically with increasing grain size, while ductility achieves a peak value at the medium grain size, contradicting with the typical behavior observed in most single-phase face-centered cubic (FCC) metallic materials deformed primarily by dislocation slips and/or twinning. The fracture behavior changes from void coalescence to quasi cleavage with grain coarsening, and the fracture mechanisms were analyzed. Additionally, the evolution of SFs and phase transformation is explored at various deformation strains.</p></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"182 ","pages":"Article 104129"},"PeriodicalIF":9.4,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142238316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Revealing the fatigue strengthening and damage mechanisms of surface-nanolaminated gradient structure","authors":"Yong Zhang ,&nbsp;Chen-Yun He ,&nbsp;Xiaogang Wang ,&nbsp;Takayuki HAMA ,&nbsp;Binhan Sun ,&nbsp;Yun-Fei Jia ,&nbsp;Xian-Cheng Zhang ,&nbsp;Shan-Tung Tu","doi":"10.1016/j.ijplas.2024.104128","DOIUrl":"10.1016/j.ijplas.2024.104128","url":null,"abstract":"<div><p>Extending the fatigue life of metals is a critical concern for maintaining material and component integrity in engineering systems. The integration of gradient structures within materials represents a highly promising approach to enhance the fatigue properties in metallic materials, while a detailed mechanistic understanding of the fatigue damage evolution of such structures is yet to be developed. Here, we report that the surface-nanolaminated gradient structure comprised of nanolaminates and hierarchical twins imparts remarkable resistance to both low-cycle and high-cycle fatigue. A dislocation-based strain gradient crystal plasticity model is developed to investigate the strengthening and damage mechanisms of our gradient structure. The size dependence of the initial dislocation density, its evolution and back stress hardening are taken into account and verified by the experimental data. The simulation results reveal that the strain delocalization and back stress hardening induced by the structure gradient significantly mitigate the fatigue damage accumulation. Additionally, in contrast to conventional gradient structures, the mechanical stability of the present structure enables these strengthening mechanisms to persist until crack initiation. These effects, combined with the sequential toughening mechanisms activated in the surface-nanolaminated gradient structure, ensure a marked life extension under low-cycle fatigue (by a factor of four), outperforming conventional gradient and other microstructural design strategies. Finally, a multiscale anti-fatigue design principal for damage homogenization is given based on the prior quantitative analysis.</p></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"182 ","pages":"Article 104128"},"PeriodicalIF":9.4,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142238315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A polycrystal plasticity-cellular automaton integrated modeling method for continuous dynamic recrystallization and its application to AA2196 alloy","authors":"Ruxue Liu ,&nbsp;Zhiwu Zhang ,&nbsp;Guowei Zhou ,&nbsp;Zhihong Jia ,&nbsp;Dayong Li ,&nbsp;Peidong Wu","doi":"10.1016/j.ijplas.2024.104127","DOIUrl":"10.1016/j.ijplas.2024.104127","url":null,"abstract":"<div><p>Continuous dynamic recrystallization usually dominates the microstructural evolution in hot working of aluminum alloys, in which the high-angle grain boundaries of new grains mainly originate from the gradual increase in subgrain misorientation angles. In this work, an integrated computational method is proposed to simulate continuous dynamic recrystallization process of aluminum alloys by coupling three-dimensional cellular automaton and visco-plastic self-consistent models. The stress response, dislocation accumulation and recovery, and evolution of crystal orientations are computed in the context of polycrystal plasticity; the formation and rotation of subgrains, followed by stored energy and curvature-driven boundary migration, are captured and visualized by cellular automaton. The non-octahedral slip mode {110}&lt;110&gt; is additionally introduced to capture the 〈001〉 texture during hot compression. A universal cell topology deformation method is adopted to achieve an effective track of grain morphology evolution during plastic deformation. The proposed simulation framework is validated through simulating the isothermal uniaxial compression process of AA2196 alloy under different temperatures and strain rates. The orientation dependence of CDRX during compression is numerically reproduced by correlating the subgrain formation and rotation process with the activation state of slip systems. The simulated macroscopic flow stress, 3D microstructure and inherent microstructural characteristics such as subgrain size, subgrain boundaries and textures are in good agreement with the experimental results. The proposed method provides an effective and efficient tool for multi-scale simulation of hot forming process of aluminum alloys.</p></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"182 ","pages":"Article 104127"},"PeriodicalIF":9.4,"publicationDate":"2024-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142235110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A generalised framework for modelling anisotropic creep-ageing deformation and strength evolution of 2xxx aluminium alloys","authors":"Xi Wang ,&nbsp;Zhusheng Shi ,&nbsp;Jianguo Lin","doi":"10.1016/j.ijplas.2024.104114","DOIUrl":"10.1016/j.ijplas.2024.104114","url":null,"abstract":"<div><div>The 2xxx aluminium alloys are extensively applied in the aerospace industry due to their lightweight and balanced performance characteristics. However, a comprehensive method for modelling both the anisotropic creep deformation and strengthening behaviour in creep age forming (CAF) for 2xxx aluminium alloys remains lacking. This paper presents a generalised framework for establishing constitutive models capable of describing the anisotropic creep deformation coupled with the microstructure and material strength evolutions during creep-ageing of both the original and the pre-deformed 2xxx series Al alloys. This framework extends the rolling direction-based material model to anisotropic scenarios at varying angles between the loading and rolling directions, by employing the non-uniform rational B-splines (NURBS). The details about the anisotropic model calibration and numerical simulation implementation are demonstrated. The feasibility of this method was verified by its application to various 2xxx series aluminium alloys with or without pre-deformation, through constitutive modelling and numerical simulation, with satisfactory agreements between prediction and experimental data. For the first time, the proposed framework provides a generalised routine for establishing anisotropic creep-ageing models for various 2xxx aluminium alloys.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"182 ","pages":"Article 104114"},"PeriodicalIF":9.4,"publicationDate":"2024-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142322192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Atomistic analysis of the mechanisms underlying irradiation-hardening in Fe–Ni–Cr alloys","authors":"A. Ustrzycka ,&nbsp;F.J. Dominguez-Gutierrez ,&nbsp;W. Chromiński","doi":"10.1016/j.ijplas.2024.104118","DOIUrl":"10.1016/j.ijplas.2024.104118","url":null,"abstract":"<div><p>This work presents a comprehensive examination of the physical mechanisms driving hardening in irradiated face-centered cubic FeNiCr alloys. The evolution of irradiation-induced defects during shear deformation is modeled by atomistic simulations through overlapping cascade simulations, where the nucleation and evolution of dislocation loops is validated by transmission electron microscopy images obtained from irradiated FeNiCr alloys using tandem accelerator. The effect of different shear rates on the microstructure of irradiated materials with a specific focus on the changes in the density of voids and dislocation loops induced by irradiation was analyzed. Additionally, the fundamental interaction processes between single irradiation-induced defects contributing to irradiation hardening, such as voids and dislocation loops in the alloy are explained. The analysis at atomic level indicates that both the dislocation loops and the voids exhibit strengthening effects. Furthermore, the nanometric voids are much stronger obstacles than dislocation loops of comparable size. The mechanism of cutting the voids leads to an increase of voids density and thus contributes to an increase in irradiation hardening. The mechanism of collapse of small voids into dislocation loops leads to decrease of voids density and at the same time increase of loops density. The coupling effect between the density of voids and dislocation loops is determined. Finally, the novel, physical mechanisms-based model of irradiation hardening and dislocation-radiation defect reaction kinetics are developed, which consider the mechanisms of void cutting, void shrink and void collapse to dislocation loop.</p></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"182 ","pages":"Article 104118"},"PeriodicalIF":9.4,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0749641924002456/pdfft?md5=eb28f8260505ab7f8addce4c82c45db4&pid=1-s2.0-S0749641924002456-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142157430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tailoring Mechanical Properties of Pearlitic Steels through Size Regulation of Multiscale Microstructures: Experiments and Simulations","authors":"Xutao Huang ,&nbsp;Yinping Chen ,&nbsp;Jianjun Wang ,&nbsp;Wenxin Wang ,&nbsp;Gang Lu ,&nbsp;Sixin Zhao ,&nbsp;Qian Li ,&nbsp;Yujie Liu ,&nbsp;Chunming Liu","doi":"10.1016/j.ijplas.2024.104110","DOIUrl":"10.1016/j.ijplas.2024.104110","url":null,"abstract":"<div><div>Pearlitic steels possess excellent mechanical properties due to their multiscale microstructures, yet this configuration introduces complex size and interface effects, impeding the elucidation of their microscopic deformation mechanisms. In this study, a predictive framework that combines a high-resolution reconstruction algorithm with a strain gradient crystal plasticity model was developed to investigate the relationship between local deformation behaviors in nodules, colonies, and lamellae of various sizes and their mechanical properties. This approach effectively reconstructs the multiscale structures of pearlite and accurately tracks the dynamic mechanical responses. The integrated experimental and computational findings highlight the critical role of microstructure sizes in regulating strain delocalization and dislocation dynamics, which, through strain partitioning and interface density, are vital for optimizing mechanical properties. Notably, a decrease in lamellar spacing and nodule size significantly enhances both strength and toughness, while smaller nodules and colonies promote increased plasticity. Finally, a dual-parameter Hall-Petch equation incorporating lamellar spacing and nodule size is introduced, enabling precise quantification of the impact of all microstructures in pearlite on mechanical properties with robust predictive capabilities.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"182 ","pages":"Article 104110"},"PeriodicalIF":9.4,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A flexible yield criterion for strength modeling from biaxial compression to biaxial tension","authors":"Lihuang Zheng ,&nbsp;Jeong Whan Yoon","doi":"10.1016/j.ijplas.2024.104113","DOIUrl":"10.1016/j.ijplas.2024.104113","url":null,"abstract":"<div><p>Accurate strength modeling from equi-biaxial tension (EBT) to equi-biaxial compression (EBC) is critical for the plastic behavior prediction covering the wide-range of stress triaxiality encountered in sheet metal forming. To date, however, few yield criteria are available that can precisely model the initial yield and hardening behavior under six typical stress states between EBC and EBT, simultaneously. Furthermore, there is still a lack of a unified yield criterion for accurate strength modeling across various stress state ranges. To address the issues, a theoretical framework for constructing yield criteria dependent on stress states is provided and a new analytically described isotropic yield criterion is presented in this study. The flexibility in terms of the yield locus and application range is thoroughly explored to make the new yield criterion general. Subsequently, the isotropic yield criterion is extended into an analytically described anisotropic-asymmetric yield criterion. Furthermore, the extended yield criterion is applied to capture the initial yield behavior of DP980, AA5754-O, and AZ31 sheets, and the strain hardening behavior of QP1180 sheets at various stress states ranging from EBC to EBT along different loading directions. The predicted results from the extended criterion agree well with the corresponding experimental findings. The applications demonstrate that the proposed anisotropic-asymmetric yield criterion can effectively model the initial yield and hardening behavior of HCP, BCC, and FCC metal sheets under EBT, EBC, uniaxial tension (UT), plane strain tension (PST), shear (SH), and uniaxial compression (UC) in an analytical way.</p></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"182 ","pages":"Article 104113"},"PeriodicalIF":9.4,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142235111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}