Materials Science and Engineering: A最新文献

{"title":"Combined impact of creep aging and helium ion irradiation on P91 steel: Experiments and FE modelling","authors":"Tao Wei,&nbsp;Alan Xu,&nbsp;Hanliang Zhu,&nbsp;Michael Drew,&nbsp;Tim Nicholls,&nbsp;Ondrej Muránsky","doi":"10.1016/j.msea.2025.148219","DOIUrl":"10.1016/j.msea.2025.148219","url":null,"abstract":"<div><div>Understanding radiation damage resistance in Grade 91 steel (P91) is essential for the development of materials for future nuclear components. This study explores the combined effects of creep aging and helium ion irradiation on the microstructure and mechanical properties of P91 steel. Creep aging was conducted under a stress of 110 MPa at 625 °C for 475 h, followed by irradiation with 5 MeV helium ions to a fluence of 5.6 × 10¹⁷ ions/cm², creating a uniform radiation-affected zone with an average damage level of 0.6 dpa. Microstructural changes and mechanical responses were assessed through detailed microstructural observations and nanoindentation, supported by finite element modelling. The results show that creep aging led to a slight reduction in hardness from 2.66 GPa to 2.45 GPa, primarily due to carbide coarsening. Significant irradiation hardening was observed, with hardness increasing by 87 % in the as-received condition and by 99 % in the creep-aged condition. A three-dimensional finite element model was developed to reverse-engineer stress-strain relationship from nanoindentation load-displacement data. This study underscores the significant impact of combined creep aging and irradiation on P91 steel, with important implications for its use in nuclear applications.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"931 ","pages":"Article 148219"},"PeriodicalIF":6.1,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143683493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Promoting grain boundary migration in CuAlMnCo alloy via nanoprecipitate-enhanced dislocation engineering","authors":"Xinghao Li,&nbsp;Ye Cui,&nbsp;Guangda Zhao,&nbsp;Weiguo Jiang,&nbsp;Lixin Sun,&nbsp;Yang Zhang,&nbsp;Zhongwu Zhang","doi":"10.1016/j.msea.2025.148215","DOIUrl":"10.1016/j.msea.2025.148215","url":null,"abstract":"<div><div>The superelastic properties of shape memory alloys (SMAs) depend strongly on their large-sized grains. Improving grain boundary (GB) migration velocity is a key to obtain large-sized grains. In this study, a multiplicative increase in GB migration velocity was achieved through tuning dislocation configuration and density by nanoprecipitates in a polycrystalline CuAlMnCo alloy. Owing to the pinning effect of the B2 nanoprecipitates, the dislocation density increased slightly, and the dislocation configuration changed from straight-like to bowed-out and tangled-like. This special dislocation configuration contributed to the formation of fine subgrains (26.0 μm) with a high misorientation (0.48°), which strongly promoted GB migration. As a result, a GB migration velocity of up to 7.1 × 10⁻⁶ m s⁻¹ was observed in the polycrystalline CuAlMnCo alloy with B2 nanoprecipitates^. An average grain size of 1.2 cm was obtained in the polycrystalline CuAlMnCo alloy containing B2 nanoprecipitates, approximately three times larger than that of the counterpart without nanoprecipitates. An excellent superelastic strain of 8.4 % was achieved in polycrystalline CuAlMnCo alloy by introducing B2 nanoprecipitates.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"931 ","pages":"Article 148215"},"PeriodicalIF":6.1,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143643534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 annealing temperature on tensile and impact properties of S31803 duplex stainless steel","authors":"Dong Young Kwon ,&nbsp;Hye-Sung Na ,&nbsp;Jae-Young Choi ,&nbsp;Jee-Hyun Kang","doi":"10.1016/j.msea.2025.148222","DOIUrl":"10.1016/j.msea.2025.148222","url":null,"abstract":"<div><div>Duplex stainless steels (DSSs) are characterized by a two-phase microstructure of ferrite and austenite, the fractions and compositions of which are known to control mechanical properties and corrosion resistance. This study investigated the tensile behavior and impact toughness of a standard DSS S31803 by analyzing microstructure and evaluating strengthening mechanisms in each phase as well as the stacking fault energy (<em>SFE</em>) of austenite. Annealing temperature changed the volume fractions and compositions of ferrite and austenite, and significantly affected both tensile and impact properties. As the annealing temperature increased, ferrite fractions and nitrogen contents in both phases rose, which improved yield strength dominantly by solid solution strengthening. Moreover, the hardness difference between the two phases became more pronounced, which intensified strain partitioning. The <em>SFE</em> of austenite ranged 21–48 mJ m⁻², and mechanical twinning was activated; however, the influence of <em>SFE</em> on tensile properties was not as significant as in lean DSSs cases in which strain-induced martensitic transformation occurred. To improve impact toughness, secondary phases should be absent and a high fraction of austenite should be present. Consequently, 1000°C, the lowest annealing temperature that could avoid detrimental secondary phases, achieved good strength-ductility combination as well as superior impact properties.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"931 ","pages":"Article 148222"},"PeriodicalIF":6.1,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143683033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 role of loading orientation on the dynamic mechanical behavior of ZK60 magnesium alloy","authors":"Chunhui Wang ,&nbsp;Jiajia Du ,&nbsp;Lingyun Qian ,&nbsp;Chaoyang Sun","doi":"10.1016/j.msea.2025.148228","DOIUrl":"10.1016/j.msea.2025.148228","url":null,"abstract":"<div><div>Magnesium alloy is a high-quality lightweight material but the poor plasticity at ambient temperature restricts its application potential. The combined effect of dynamic condition and loading orientation is believed to extend the ductility of magnesium alloy, while the mechanism underlying orientation-dependent dynamic deformation is still poorly understood. The dynamic mechanical behaviors as well as microstructure evolutions were evaluated on ZK60 Mg alloy via dynamic tension in both extrusion direction (ED) and transverse direction (TD) with strain rates of 2000 s⁻¹, 3200 s⁻¹ and 4300 s⁻¹ using the split Hopkinson tensile bar (SHTB), and quasi-static tension with 0.001 s⁻¹ strain rate. Subsequent electron back-scattered diffraction (EBSD) observation and scanning electron micrograph (SEM) of fracture surfaces, employing an interrupt strain test method, was conducted to elucidate the loading orientation correlations for dynamic deformation. The dynamic deformation mechanisms in the initial stage, are primarily governed by non-basal slip in ED and extension twinning in TD, as indicated by Schmid factor (SF) calculations and confirmed by misorientation angle distributions. This renders positive strain rate sensitivity (SRS) for the former, whereas rate-insensitive behavior for the latter. The non-basal slip allows rapid dislocation multiplication in the ED, while the phenomenon is delayed in the TD until about 0.05 strain, at which the SRS is highlighted. More intense interaction between first-formed twins and later-activated dislocations contributes to higher strain hardening and elongation due to the dynamic loading in TD. In the later stages of dynamic strain, the adiabatic temperature of ∼80 °C in TD is also regarded as the source of the decreasing strain hardening and increasing elongation, evidenced by the fracture mode transitions from quasi-brittle to ductile compared to quasi-static tension.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"931 ","pages":"Article 148228"},"PeriodicalIF":6.1,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143683498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modeling of temperature-sensitive anisotropic behavior of AZ31B magnesium alloy sheets: Integration of polycrystal plasticity and yield function calibration","authors":"Jiali Pang ,&nbsp;Sumio Sugiyama ,&nbsp;Jun Yanagimoto","doi":"10.1016/j.msea.2025.148227","DOIUrl":"10.1016/j.msea.2025.148227","url":null,"abstract":"<div><div>Accurate modeling of the temperature-sensitive in-plane anisotropic behavior of Mg alloys using finite element method simulations is crucial for the widespread application of this environmentally friendly material. This study evaluates the applicability and accuracy of using a polycrystalline plasticity model to calibrate phenomenological models for AZ31B magnesium alloy sheets across multiple temperature scales. Mechanical tests including uniaxial tension tests, and layer and disk compression tests were conducted at various temperatures (25–250 °C) to obtain anisotropic data. A part of the experimental data was utilized to identify the viscoplastic self-consistent polycrystal plasticity (VPSC) model based on the texture information of the material. Subsequently, virtual experiments were conducted within the VPSC model to simulate the anisotropic parameters of the alloy under various temperature conditions. These parameters were next employed to calibrate three yield functions and compared with corresponding results calibrated based on the experimental data. The approach demonstrated an exceptional capability in fitting the experimental results in most cases, although the interference from grain activities influences the accuracy of VPSC model in predicting the R-values at higher temperatures. Overall, this approach is practical for enhancing the accuracy of anisotropy modeling across temperature scales with a few conveniently obtainable tests. Moreover, among the yield functions, Yld 2004-18p provided the most accurate modeling of the anisotropic behavior of the Mg alloy sheet.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"931 ","pages":"Article 148227"},"PeriodicalIF":6.1,"publicationDate":"2025-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143683037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Achieving superior strength and ductility in TiAl/Ti2AlNb dissimilar brazed joints by controlling the brittle Zr(Ni,Cu)3 intermetallic compound","authors":"Tian Hao ,&nbsp;Jie Xiong ,&nbsp;Lei Zhao ,&nbsp;Jun Mei ,&nbsp;Yan Qi ,&nbsp;Jian-chao He ,&nbsp;Tong-Yi Zhang","doi":"10.1016/j.msea.2025.148225","DOIUrl":"10.1016/j.msea.2025.148225","url":null,"abstract":"<div><div>By optimizing the composition of filler metals, this research maximized the solid-solution strengthening effect of Zr while suppressing the precipitation of brittle Zr(Ni,Cu)₃ intermetallic compound, thereby achieving the robust brazing bonding of Ti-48Al-2Cr-2Nb (at.%) (Ti4822) and Ti-22Al-25Nb (at.%) (Ti₂AlNb) with an optimal balance of strength and toughness. The microstructure of Ti4822/Ti₂AlNb brazed joints was characterized and analyzed with Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), Transmission Electron Microscopy (TEM), and Electron Backscatter Diffraction (EBSD) techniques. Additionally, the micro-hardness of the existing phases and the tensile properties of the brazed joints under room-temperature were evaluated. The results reveal that the presence of α₂-Ti₃Al, B2, Ti(Zr)(Ni,Cu)₃ phases in Ti4822/Ti₂AlNb joints. The solid-solution strengthening effect of Zr element on the joint microstructure and its promotion of the formation of ductile B2 phase were confirmed. When the Zr content in the filler metal reached 15 wt%, the precipitation conditions for the continuous Zr(Ni,Cu)₃ at the center of the joint were satisfied. The incoherent interface formed between it and the α₂-Ti₃Al, was identified as the primary cause of the fracture failure. The tensile tests at room temperature on the Ti4822/Ti_57.5Zr_12.5Cu₁₅Ni₁₅/Ti₂AlNb joint, obtained by holding at 980 °C for 60 min, exhibits the highest tensile strength of 522.12 ± 18.8 MPa and the elongation of 1.34 ± 0.07 %. The strength and ductility of this brazed joint surpass previously reported results. Basing on that, a novel Ti-Zr-Cu-Ni amorphous filler metal suitable for the brazing of Ti4822 and Ti₂AlNb intermetallic compound alloys has been developed.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"931 ","pages":"Article 148225"},"PeriodicalIF":6.1,"publicationDate":"2025-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143683492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of hierarchical microstructure on mechanical properties in sintered CoCrFeMnNi high-entropy alloy fabricated by ultrasonic nanocrystalline surface modification","authors":"Do Won Lee ,&nbsp;Rae Eon Kim ,&nbsp;Hyojeong Ha ,&nbsp;Auezhan Amanov ,&nbsp;Hyeong Seop Kim","doi":"10.1016/j.msea.2025.148218","DOIUrl":"10.1016/j.msea.2025.148218","url":null,"abstract":"<div><div>Ultrasonic nanocrystal surface modification adopted in as-sintered porous CoCrFeMnNi high-entropy alloys reduces residual porosity and enhances mechanical properties. This treatment forms a gradient structure with a hardened surface and ductile core, achieving approximately reduced surface porosity by 75–78 %, increased yield strength by 106–119 %, and ultimate tensile strength by 15–22 %, respectively.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"931 ","pages":"Article 148218"},"PeriodicalIF":6.1,"publicationDate":"2025-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143683497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 niobium addition on the microstructure, transformation temperatures, and shape memory effect of Cu-Al-Ni-Ti shape memory alloys","authors":"Arya Mohammadzadeh,&nbsp;Shahram Raygan","doi":"10.1016/j.msea.2025.148181","DOIUrl":"10.1016/j.msea.2025.148181","url":null,"abstract":"<div><div>This research aims to study the effect of adding Nb element on the microstructure, transformation temperatures, mechanical properties, and shape memory effect of Cu-Al-Ni-Ti alloys prepared by the vacuum arc remelting method. Various analyses, such as optical microscopy, scanning electron microscopy, and transmission electron microscopy, were used to investigate the microstructure, the differential scanning calorimetry test to study the transformation temperatures, and X-ray diffraction to study the existing phases. The obtained results showed that by adding 0.5 (wt.%) Nb element to Cu-13Al-4Ni-0.7Ti (wt.%) alloy with martensitic structure at room temperature, the grain size decreased from 260 to 188 μm, and the failure stress and strain increased from 361 MPa and 6.4 % to 506 MPa and 7.9 %, respectively. Microscopic studies indicated the formation of Nb-rich second-phase particles next to Ti-rich phases in the alloy microstructure. The Cu-13Al-4Ni-0.7Ti-0.5Nb alloy (wt.%) exhibited transformation temperatures <span><math><mrow><msub><mi>M</mi><mi>s</mi></msub></mrow></math></span>, <span><math><mrow><msub><mi>M</mi><mi>f</mi></msub></mrow></math></span>, <span><math><mrow><msub><mi>A</mi><mi>s</mi></msub></mrow></math></span>, and <span><math><mrow><msub><mi>A</mi><mi>f</mi></msub></mrow></math></span> equal 110, 86, 131, and 163 °C, respectively. This alloy possesses a high potential for practical applications due to its 100 % recoverability with a pre-strain of 2 %.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"931 ","pages":"Article 148181"},"PeriodicalIF":6.1,"publicationDate":"2025-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143682991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microstructure and mechanical properties of AlMo0.5NbTa0.5TiZr refractory high-entropy alloys fabricated by laser melting deposition","authors":"Xinzhou Zhang ,&nbsp;Zhiyuan Zheng ,&nbsp;Bingbing Sun ,&nbsp;Hui Han ,&nbsp;Xiaoming Chen ,&nbsp;Lan Chen","doi":"10.1016/j.msea.2025.148213","DOIUrl":"10.1016/j.msea.2025.148213","url":null,"abstract":"<div><div>The low-density refractory high-entropy alloy AlMo_0.5NbTa_0.5TiZr exhibits excellent high-temperature strength, high-temperature creep resistance, and high-temperature corrosion resistance, making it an ideal material for high-temperature structural applications. AlMo_0.5NbTa_0.5TiZr was formed using electromagnetic induction heating-assisted laser melting deposition (LMD). The influence of laser process parameters on the dendritic morphology of AlMo_0.5NbTa_0.5TiZr was analyzed for the first time, especially the effect of laser power on the diffusion behavior of elements. The mechanism of how elemental diffusion affects the microstructure and mechanical properties was also revealed. The results indicated that at higher laser power, coarse dendritic arms developed within the AlMo_0.5NbTa_0.5TiZr specimens. The dendritic region was enriched with the high melting point Mo-Nb-Ta BCC-1 phase, while the inter-dendritic region was primarily enriched with the low melting point Al-Zr-Ti BCC-2 phase. The increase in laser power led to a significant rise in the Al-Zr enriched Al₃Zr₄ phase. Compared to traditional vacuum arc melting method, AlMo_0.5NbTa_0.5TiZr formed by LMD exhibited a finer grain structure and superior mechanical properties. At a laser power of 1600 W, the average hardness and ultimate compressive strength of the LMD-formed AlMo_0.5NbTa_00.5TiZr specimens reached their maximum values, with the highest average hardness of 660 HV and the ultimate compressive strength of 2012 MPa. This study offers valuable insights into the application of LMD technology for processing novel low-density refractory high-entropy alloys, fostering the future development and application of innovative RHEAs in high-performance fields such as aerospace and energy.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"931 ","pages":"Article 148213"},"PeriodicalIF":6.1,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143683098","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heterogeneous microstructures of martensite and pearlite achieving excellent mechanical properties in high carbon chromium steel by multi-cycle flash heating treatment","authors":"Changqing Shu ,&nbsp;Shasha Zhang ,&nbsp;Mengxin Yao ,&nbsp;Peiheng Ding ,&nbsp;Jicong Zhang ,&nbsp;Xuewei Tao ,&nbsp;Xiaolin Zhu ,&nbsp;Shuaipeng Yu ,&nbsp;Qiuhao Gu ,&nbsp;Liukai Hua ,&nbsp;Zhengjun Yao","doi":"10.1016/j.msea.2025.148214","DOIUrl":"10.1016/j.msea.2025.148214","url":null,"abstract":"<div><div>Traditional homogeneous microstructures such as martensite, bainite, and pearlite struggle to balance strength and ductility in high carbon chromium steels. This study introduces a novel approach to achieving strength-ductility synergy by developing heterogeneous microstructures of martensite and pearlite during the continuous cooling transformation of supercooled austenite. By applying flash heating treatment, we achieved austenite chemical heterogenization and retained some undissolved carbides. We controlled the heating rate and the number of cycles to allow the pearlite volume fraction to vary between 24.8 % and 59.7 %. The samples subjected to multi-cycle flash heating exhibited fine grain sizes (1.08 μm) and higher dislocation densities, attaining a yield strength of 1294 MPa, an ultimate tensile strength of 1605 MPa and an elongation of 9.8 %. The enhanced mechanical properties were primarily attributed to dislocation hardening, grain refinement, and hetero-deformation-induced stress resulting from the coexistence of martensite and pearlite phases. This study provides a new strategy for optimizing the mechanical properties of high carbon chromium steels and provides valuable insights for advancing the development of other materials with excellent mechanical properties.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"931 ","pages":"Article 148214"},"PeriodicalIF":6.1,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143637129","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}