Journal of Magnesium and Alloys最新文献

Synergistic optimization of efficiency-microstructure-performance in wire-arc additive manufacturing of AZ31 magnesium alloy AZ31镁合金线弧增材制造效率-组织-性能协同优化

IF 17.6 1区材料科学

Journal of Magnesium and Alloys Pub Date : 2025-05-28 DOI: 10.1016/j.jma.2025.04.026

Zihao Jiang, Caiyou Zeng, Zijin Chang, Ziqi Li, Yuan Zhao, Baoqiang Cong

{"title":"Synergistic optimization of efficiency-microstructure-performance in wire-arc additive manufacturing of AZ31 magnesium alloy","authors":"Zihao Jiang, Caiyou Zeng, Zijin Chang, Ziqi Li, Yuan Zhao, Baoqiang Cong","doi":"10.1016/j.jma.2025.04.026","DOIUrl":"https://doi.org/10.1016/j.jma.2025.04.026","url":null,"abstract":"In wire arc additive manufacturing (WAAM), a trade-off exists among deposition efficiency, microstructure, and mechanical properties. Addressing this challenge, this work proposes an innovative multi-objective optimization framework tailored for WAAM of AZ31 magnesium alloy components, which integrates deposition efficiency and microstructure as coupled objectives and is resolved through the NSGA-II algorithm. The proposed framework employs quadratic regression to correlate process parameters with deposition efficiency through geometric morphology mediation, while addressing uncertainties in WAAM by integrating theoretical insights with data-driven stacked ensemble learning for grain size prediction, establishing the hybrid physics-informed data method for WAAM microstructure prediction. The optimized process achieved a deposition rate of 6257 mm³/min, with effective width and average layer height maintained at 10.1 mm and 4.13 mm, respectively. Microstructural optimization produced a fine, uniform, fully equiaxed grain structure with an average grain size of 38 μm. These findings underscore the significant industrial potential of intelligent optimization strategies in WAAM for manufacturing lightweight, high-performance components in aerospace and transportation sectors.","PeriodicalId":16214,"journal":{"name":"Journal of Magnesium and Alloys","volume":"9 1","pages":""},"PeriodicalIF":17.6,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144153373","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}

引用次数: 0

Comparative study of dynamic recrystallization behavior, microstructural characteristics, and mechanical properties of high-speed-extruded AZ31 and BA56 magnesium alloys 高速挤压AZ31与BA56镁合金动态再结晶行为、显微组织特征及力学性能的对比研究

IF 17.6 1区材料科学

Journal of Magnesium and Alloys Pub Date : 2025-05-28 DOI: 10.1016/j.jma.2025.04.020

Gun Woong An, Sang-Cheol Jin, Taekyung Lee, Sumi Jo, Sung Hyuk Park

{"title":"Comparative study of dynamic recrystallization behavior, microstructural characteristics, and mechanical properties of high-speed-extruded AZ31 and BA56 magnesium alloys","authors":"Gun Woong An, Sang-Cheol Jin, Taekyung Lee, Sumi Jo, Sung Hyuk Park","doi":"10.1016/j.jma.2025.04.020","DOIUrl":"https://doi.org/10.1016/j.jma.2025.04.020","url":null,"abstract":"This study compares the microstructural evolution, dynamic recrystallization (DRX) behavior, tensile properties, and age-hardenability between the newly developed high-speed-extrudable BA56 alloy and those of the widely recognized AZ31 alloy in industry. Unlike the AZ31 alloy, which retains partially unrecrystallized grains, the high-speed-extruded BA56 alloy demonstrates a coarser but entirely recrystallized and more homogeneous microstructure. The fine-grained structure and abundant Mg3Bi2 particles in the BA56 extrusion billet significantly enhance its DRX behavior, thus enabling rapid and complete recrystallization during extrusion. The BA56 alloy contains band-like fragmented Mg₃Bi₂ particles and numerous fine Mg₃Bi₂ particles distributed throughout the material, in contrast to the sparse Al₈Mn₅ particles in the AZ31 alloy. These features contribute to superior mechanical properties of the BA56 alloy, which achieves tensile yield and ultimate tensile strengths of 205 and 292 MPa, respectively, compared to 196 and 270 MPa for the AZ31 alloy. The superior strength of the BA56 alloy, even with its coarser grain size, can be explained by its elevated Hall-Petch constant and the strengthening contribution from the fine Mg₃Bi₂ particles. Additionally, the BA56 alloy demonstrates significant age-hardenability, achieving a 22% enhancement in hardness following T5 aging, attributed to the precipitation of nanoscale Mg₃Bi₂ and Mg₁₇Al₁₂ phases. By contrast, the AZ31 alloy shows minimal hardening due to the absence of precipitate formation during aging. These findings suggest that the BA56 alloy is a promising candidate for the production of extruded Mg components requiring a combination of high productivity, superior mechanical performance, and wide-ranging process adaptability.","PeriodicalId":16214,"journal":{"name":"Journal of Magnesium and Alloys","volume":"83 1","pages":""},"PeriodicalIF":17.6,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144153374","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}

引用次数: 0

The interfacial reactions of Mg battery anodes 镁电池阳极的界面反应

IF 17.6 1区材料科学

Journal of Magnesium and Alloys Pub Date : 2025-05-26 DOI: 10.1016/j.jma.2025.04.031

Xuehong Luo, Ao Shen, Bo Liu, Junjie Wu, Mengbiao Fan, Na Yang, Gaopeng Zhang, Xi Chen, Qingwei Dai

引用次数: 0

Effective catalytic effects of Mo2C MXene on the hydrogen storage in magnesium hydride Mo2C MXene对氢化镁储氢的有效催化作用

IF 17.6 1区材料科学

Journal of Magnesium and Alloys Pub Date : 2025-05-22 DOI: 10.1016/j.jma.2025.04.029

Xiaojiao Wang, Zhenluo Yuan, Yang Shi, Shangsheng Li, Guofa Mi, Qiuming Peng, Shumin Han, Yanping Fan, Baozhong Liu

{"title":"Effective catalytic effects of Mo2C MXene on the hydrogen storage in magnesium hydride","authors":"Xiaojiao Wang, Zhenluo Yuan, Yang Shi, Shangsheng Li, Guofa Mi, Qiuming Peng, Shumin Han, Yanping Fan, Baozhong Liu","doi":"10.1016/j.jma.2025.04.029","DOIUrl":"https://doi.org/10.1016/j.jma.2025.04.029","url":null,"abstract":"Magnesium hydride (MgH2) has received widespread attention because of its high hydrogen capacity and low cost, but the sluggish kinetics limited its practical application. Herein, the two-dimensional Mo2C MXene was constructed to motivate the efficient hydrogen storage in MgH2 for the first time. After doping 10 wt% Mo2C MXene, the starting dehydriding temperature was lowered to 225 °C, presenting a 117 °C reduction compared with that of as-received MgH2. The 10 wt% Mo2C-containing MgH2 sample could rapidly release 6.7 wt% H2 in 13 min at 300 °C, and the product after hydrogen release could absorb 6.0 wt% H2 in 12 min at 200 °C, showing superior hydriding and dehydriding kinetics. Moreover, the activation energy (Ea) of MgH2–10 wt% Mo2C (107.58 ± 1.57 kJ/mol) was obviously lower than that of pure MgH2 (130.45 ± 1.97 kJ/mol), and the reduced activation energy explained the reduced dehydrogenation temperature and enhanced kinetics. Microstructure characterization revealed that Mo-species (Mo0 and Mo2+) formed during ball milling served as active species accelerated the hydriding/dehydriding reactions, and the uniformly distributed active species and the interaction between Mo and O jointly promoted the hydrogen storage properties of MgH2.","PeriodicalId":16214,"journal":{"name":"Journal of Magnesium and Alloys","volume":"91 1","pages":""},"PeriodicalIF":17.6,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144113351","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}

引用次数: 0

A novel flame retardant strategy for molten magnesium alloys: The effect of the new protective gas C3H2F6 on EV33 alloy 一种新型的熔融镁合金阻燃策略：新型保护气体C3H2F6对EV33合金的影响

IF 17.6 1区材料科学

Journal of Magnesium and Alloys Pub Date : 2025-05-22 DOI: 10.1016/j.jma.2025.04.021

Longbiao Feng, Lunyong Zhang, Hongxian Shen, Chaojun Zhang, Zhi Song, Jiaming Cao, Fuyang Cao, Zhiliang Ning, Yongjiang Huang, Jianfei Sun

{"title":"A novel flame retardant strategy for molten magnesium alloys: The effect of the new protective gas C3H2F6 on EV33 alloy","authors":"Longbiao Feng, Lunyong Zhang, Hongxian Shen, Chaojun Zhang, Zhi Song, Jiaming Cao, Fuyang Cao, Zhiliang Ning, Yongjiang Huang, Jianfei Sun","doi":"10.1016/j.jma.2025.04.021","DOIUrl":"https://doi.org/10.1016/j.jma.2025.04.021","url":null,"abstract":"Resolving the ignition issue of magnesium alloys is essential for broadening their application scope. This research investigates the EV33 magnesium alloy, delving into an innovative flame-retardant strategy, with a specific focus on the impact of the novel protective gas C3H2F6 on the flame-retardant properties of the alloy. This paper unveils the morphological characteristics of the EV33 magnesium alloy surface in the absence of protective gas, while employing thermodynamic principles to establish the preferential reaction stages of the alloy, computing the residual stress of MgF2, and assessing the flame-retardant and antioxidative properties of C3H2F6. The study finds that under conditions without protective gas, the oxide film on the EV33 alloy surface is prone to cracking, which accelerates the ignition process of the alloy. Conversely, in an environment enriched with C3H2F6, the formation of a dense oxide film on the alloy surface significantly enhances its thermal stability and flame-retardant properties. This mechanism encompasses the formation of a secondary oxide film, where C3H2F6 accelerates the rapid development of this film, effectively repairing damage to the primary oxide film and inhibiting further diffusion of the oxidation reaction. Furthermore, this study elucidates the origin of oxide film rupture, showing that under conditions without protective gas, the precipitated phases and grain boundaries on the surface of the alloy induce the rupture of the oxide film, attributed to stress concentration phenomena occurring around the grain boundaries.","PeriodicalId":16214,"journal":{"name":"Journal of Magnesium and Alloys","volume":"135 1","pages":""},"PeriodicalIF":17.6,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144113724","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}

引用次数: 0

Wire-based friction stir additive manufacturing of AZ31B magnesium alloy: Precipitate behavior and mechanical properties AZ31B镁合金丝基搅拌摩擦添加剂制备：析出行为及力学性能

IF 17.6 1区材料科学

Journal of Magnesium and Alloys Pub Date : 2025-05-22 DOI: 10.1016/j.jma.2025.04.025

Xiuwen Sun, Yuming Xie, Xiangchen Meng, Zeyu Zhang, Huijia Tian, Wenjiang Dong, Jianing Dong, Xiaotian Ma, Naijie Wang, Yongxian Huang

{"title":"Wire-based friction stir additive manufacturing of AZ31B magnesium alloy: Precipitate behavior and mechanical properties","authors":"Xiuwen Sun, Yuming Xie, Xiangchen Meng, Zeyu Zhang, Huijia Tian, Wenjiang Dong, Jianing Dong, Xiaotian Ma, Naijie Wang, Yongxian Huang","doi":"10.1016/j.jma.2025.04.025","DOIUrl":"https://doi.org/10.1016/j.jma.2025.04.025","url":null,"abstract":"Simultaneous achievement of defect-free formation and high mechanical performance in additive manufactured Mg alloys remains challenging, bottlenecked by flammability, porosities, and oxidation risks within the melting-solidifying process. Here, wire-based friction stir additive manufacturing (W-FSAM), sparked by continuous wire feeding, severe plastic deformation transport, and solid-state deposition, was exploited to achieve sound Mg components. Greatly refined grains were obtained by severe plastic deformation, with an average grain size of 3.79 µm. Al8Mn5 precipitates underwent refinement and redistribution, while Mg17Al12 precipitates experienced solid solution and precipitation behaviors. Lattice mismatch was 4.92 % when Mg17Al12 precipitated on Al8Mn5. The strong flow-induced effect of the pin structure weakened the basal texture along the building direction, which was formed by the intense forging effect of W-FSAM tools. Alternating texture features coordinated the plastic deformation of slip and twinning, enabling superior ductility. Additionally, in-situ electron backscattered diffraction results revealed grain boundary sliding accommodated by grain rotation within the fine-grained structure. These unique microstructural features and precipitate behavior enhanced the overall mechanical properties, with an ultimate tensile strength of 257.3 ± 3.5 MPa and an elongation of 12.4 ± 0.3 % in building direction, and an ultimate tensile strength of 250.7 ± 2.0 MPa and an elongation of 12.2 ± 0.5 % in the traveling direction.","PeriodicalId":16214,"journal":{"name":"Journal of Magnesium and Alloys","volume":"1 1","pages":""},"PeriodicalIF":17.6,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144122432","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}

引用次数: 0

Abnormal grain growth mechanism and inhibiting strategy by a tailored two-step solution treatment of ZK60 Mg alloy ZK60镁合金两步固溶处理的异常晶粒生长机理及抑制策略

IF 17.6 1区材料科学

Journal of Magnesium and Alloys Pub Date : 2025-05-22 DOI: 10.1016/j.jma.2025.04.024

Guanghan Dang, Liang Chen, Jianwei Tang, Yuhui Zhao, Cunsheng Zhang, Xiangshan Kong

{"title":"Abnormal grain growth mechanism and inhibiting strategy by a tailored two-step solution treatment of ZK60 Mg alloy","authors":"Guanghan Dang, Liang Chen, Jianwei Tang, Yuhui Zhao, Cunsheng Zhang, Xiangshan Kong","doi":"10.1016/j.jma.2025.04.024","DOIUrl":"https://doi.org/10.1016/j.jma.2025.04.024","url":null,"abstract":"Mg profiles extruded through porthole die inherently contain longitudinal welds, which can readily induce the abnormal grain growth (AGG) in solution treatment at elevated temperature. Here, a strategy of two-step (primary and secondary) solution is tailored to inhibit AGG. The results indicate that AGG during primary solution can only be suppressed when the temperature drops below 300 °C, while these samples experienced AGG during secondary solution. It is interesting that the width of abnormal grain after secondary solution significantly decreases from 1,473 to 71 µm with increasing the holding time of primary solution from 3 to 84 h. This inhibiting effect results in notable enhancements in mechanical properties, where the elongation, initial fracture points, and maximum bending force are improved by 88.58 %, 32.63 %, and 128.50 %, respectively. The dislocation density and types of the precipitated phases after primary solution are the main factors for inhibiting AGG. First, the dislocation density decreases with increasing the time of primary solution, reducing the stored energy in grain interior. Second, as the primary solution time is extended, MgZn2 phases greatly become coarsening, accompanied by a transition in their relationship with α-Mg from coherent to semi-coherent. Moreover, the quantities of Mg4Zn7 (non-coherent with α-Mg) and Mg2Zn3 (semi-coherent with α-Mg) undergo a substantial increase, contributing to a high interfacial energy that effectively inhibits the grain boundary migration during secondary solution.","PeriodicalId":16214,"journal":{"name":"Journal of Magnesium and Alloys","volume":"127 1","pages":""},"PeriodicalIF":17.6,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144113675","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}

引用次数: 0

Microstructure evolution of laser directed energy deposition process prepared CNTs/WE43 composites during solution and aging treatment 激光定向能沉积工艺制备的CNTs/WE43复合材料在固溶和时效过程中的组织演变

IF 17.6 1区材料科学

Journal of Magnesium and Alloys Pub Date : 2025-05-22 DOI: 10.1016/j.jma.2025.04.015

引用次数: 0

Optimizing the fluidity in thin-section investment casting for vacuum induction molten AZ91D-1 %wt. CaO az91d - 1% wt真空感应熔液薄壁熔模铸造流动性的优化。曹

IF 17.6 1区材料科学

Journal of Magnesium and Alloys Pub Date : 2025-05-22 DOI: 10.1016/j.jma.2025.04.028

V.H. Carneiro, V. Lopes, I. Duarte, H. Puga

{"title":"Optimizing the fluidity in thin-section investment casting for vacuum induction molten AZ91D-1 %wt. CaO","authors":"V.H. Carneiro, V. Lopes, I. Duarte, H. Puga","doi":"10.1016/j.jma.2025.04.028","DOIUrl":"https://doi.org/10.1016/j.jma.2025.04.028","url":null,"abstract":"This paper discusses an experimental investigation into the fluidity of AZ91D-1 %wt. CaO magnesium melt via induction for thin-section investment casting. Plaster molds with thin spiral cavities (0.5 to 1.5 mm square sections) were designed and manufactured to assess the impact of casting conditions on filling length, as magnesium alloys cause severe melting and melt-mold exothermic reactions, making investment casting challenging. Combinations of traditional Mg-mold reaction mitigation techniques, such as applying a protective mold coating (Yttria) and vacuum, were examined to determine their role in the filling process. The results suggest that when induction is employed to melt reactive alloys, these methods are not always beneficial, as initially thought. Particularly at higher melt temperatures, the combination of Yttria-coated molds with low-pressure vacuum induction significantly reduce fluidity: vacuum induced melt levitation which promotes oxidation with the residual atmosphere; and Yttria-coating cracking due to thermal stress during the mold fabrication slows filling and promotes significant melt-mold reaction. This study shows that best results to investment cast thin-sections are obtained by avoiding both vacuum and protective coatings, providing a viable route for the precision manufacturing of stent biomedical devices.","PeriodicalId":16214,"journal":{"name":"Journal of Magnesium and Alloys","volume":"15 1","pages":""},"PeriodicalIF":17.6,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144113725","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}

引用次数: 0

Synergization of yield strength and ductility for a dilute Mg-Zn-Nd-Ca alloy through pinned twin boundary and Guinier–Preston zone 通过钉住孪晶界和Guinier-Preston区，稀Mg-Zn-Nd-Ca合金屈服强度和塑性的协同作用

IF 17.6 1区材料科学

Journal of Magnesium and Alloys Pub Date : 2025-05-21 DOI: 10.1016/j.jma.2025.04.027

Xin Wan, Maolin Yin, Chao Zeng, Weilin Liu, Peng Peng, Linsong Zhang, Bi Jia, Jianyue Zhang, Qingshan Yang, Qingwei Dai

{"title":"Synergization of yield strength and ductility for a dilute Mg-Zn-Nd-Ca alloy through pinned twin boundary and Guinier–Preston zone","authors":"Xin Wan, Maolin Yin, Chao Zeng, Weilin Liu, Peng Peng, Linsong Zhang, Bi Jia, Jianyue Zhang, Qingshan Yang, Qingwei Dai","doi":"10.1016/j.jma.2025.04.027","DOIUrl":"https://doi.org/10.1016/j.jma.2025.04.027","url":null,"abstract":"Mg-Zn-RE alloys typically exhibit non-basal texture, weak dispersion hardening, and low yield strength. In this study, we designed a dilute quaternary Mg-0.6Zn-0.4Nd-0.2Ca (wt.%) alloy. Then, applied pre-strain and heat treatment to investigate the balance of yield strength and ductility via solute atom segregation at twin boundaries and nanophase modifications. The results indicated that Zn and Nd elements tend to co-segregate at the twin boundary, while Ca element segregates alone and presents a discontinuous distribution. Nanoscale precipitates of (Mg, Zn)3Nd and Mg2Ca with the size of 5∼20 nm underwent significant preferential precipitation at the twin boundary. Moreover, compared with Ca atoms, Zn atoms tend to combine with Nd atoms more preferentially towards the stacking faults, thereby forming a high-density monolayer Guinier-Preston (G.P.) zone. The segregation and precipitation of solute atoms at the twin boundary and the stacking faults increased the friction stress of twinning dislocations and lattice dislocations, thus improving the strength. Pinned twin boundaries facilitate the transition from basal 〈a〉 slip to pyramidal 〈c + a〉 slip due to the small geometrical compatibility factor (m′) value as well as the Schmid factor (SF) incompatibility. As a result, the pre-strained and heat-treated specimen's yield strength exhibits a 141 % increase relative to the initial state specimen, accompanied by a modest improvement in ductility. The mechanism of multi-element segregation and precipitation at twin boundaries, and G.P. zone formation was discussed in detail.","PeriodicalId":16214,"journal":{"name":"Journal of Magnesium and Alloys","volume":"63 1","pages":""},"PeriodicalIF":17.6,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144104180","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}

引用次数: 0