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Multi-physical fields distribution in billet during helical electromagnetic stirring:A numerical simulation research
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作者 Dong Pan Qing-tao Guo +3 位作者 Kai-lun Zhang Fu-zhi Yu Yu-ying Li Yu-bao Xiao 《China Foundry》 SCIE EI CAS CSCD 2024年第1期51-59,共9页
Electromagnetic stirring is one of the widely applied techniques to modify the quality of casting billets.Different from conventional rotate stirring,the helical stirring is more professional in assisting multi-dimens... Electromagnetic stirring is one of the widely applied techniques to modify the quality of casting billets.Different from conventional rotate stirring,the helical stirring is more professional in assisting multi-dimensional flow of molten metal and eliminating solidification defects.In this study,the single-winding helical stirring(SWHS)was introduced,offering advantages such as smaller volume and lower electromagnetic shielding compared to traditional helical stirring methods.Following a comprehensive numerical simulation,the stirring parameters of SWHS were adjusted to yoke inclination angle of 43°and frequency of 12 Hz.The higher electromagnetic force and flow velocity in drawing direction,as well as the lower temperature gradient induced by the SWHS,are positive factors for homogeneous solidification of billet.The experimental results on Al-8%Si alloy and 0.4%C-1.1%Mn steel demonstrate that compared to rotate stirring,the SWHS process can induce better billet quality and is more effective in accelerating the equiaxed expansion and reducing element segregation.The SWHS process can enhance the equiaxed ratio of the billet by 58.3%and reduce segregation degree of carbon element by 10.97%.Consequently,SWHS holds great promise as a potential approach for improving the quality of continuous casting billets. 展开更多
关键词 BILLET electromagnetic stirring HELICAL SOLIDIFICATION element segregation numerical simulation
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Degradation of acid fuchsine by a modified electro-Fenton system with magnetic stirring as oxygen supplying 被引量:2
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作者 Yiping Sheng,Limin Zhen,Xiuli Wang,Ning Li,Qi Tong College of Environmental and Chemical Engineering,Yanshan University,Qinhuangdao,Hebei 066004,China. 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2010年第4期547-554,共8页
The current modified electro-Fenton system was designed to develop a more convenient and efficient undivided system for practical wastewater treatment. The system adopted a cathode portion that employed magnetic stirr... The current modified electro-Fenton system was designed to develop a more convenient and efficient undivided system for practical wastewater treatment. The system adopted a cathode portion that employed magnetic stirring instead of common oxygen gas diffusion or gas sparging to supply oxygen gas for the electrolyte solution. Key factors influencing the cathode fabrication and activit) were investigated. The degradation of acid fuchsine with a self-made graphite-polytetrafluorethylene cathode was studied using spectrophotometer. It was found that the cathode generated hydrogen peroxide with high current efficiency and the hydrogen peroxide yield of the cathode did not decay after 10 times reuse. With the Pt anode at a ferrous ion concentration of 0.5 mmol/L, a pH of 3, and using magnetic stirring, dye decolorization could be rapidly accomplished but the destruction of benzene rings and intermediates was fairly difficult. With a Fe anode, dye degradation was more complete. 展开更多
关键词 electro-Fenton system oxygen gas magnetic stirring acid fuchsine DEGRADATION
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Mechanical properties and microstructural evolution of rheocast A356 semi-solid slurry prepared by annular electromagnetic stirring 被引量:1
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作者 Mohammad Taghi Asadi Khanouki 《China Foundry》 SCIE CAS CSCD 2023年第4期315-328,共14页
Nowadays,having an effective technique in preparing semi-solid slurries for rheocasting process seems to be an essential requirement.In this study,semi-solid slurry of A356 aluminum alloy was prepared by three-phase a... Nowadays,having an effective technique in preparing semi-solid slurries for rheocasting process seems to be an essential requirement.In this study,semi-solid slurry of A356 aluminum alloy was prepared by three-phase annular electromagnetic stirring(A-EMS)technique under different conditions.The effects of stirring current,pouring temperature and stirring time on microstructural evolution,mean particle size,shape factor and solid fraction were investigated.The rheocasting process was carried out by using a drop weight setup and to inject the prepared semi-solid slurry in optimal conditions into the step-die cavity.The filling behavior and mechanical properties of parts were studied.Microstructural evolution showed that the best semi-solid slurry which had fine spherical particles with the average size of~27μm and a shape factor of~0.8 was achieved at the stirring current of 70 A,melt pouring temperature of 670℃,and stirring time of 30 s.Under these conditions,the step-die cavity was completely filled at die preheating temperature of 470℃.The hardness increases by decreasing step thickness as well as die preheating temperature.Moreover,the tensile properties are improved at lower die preheating temperatures.The fracture surface,which consists of a complex topography,indicates a typical ductile fracture. 展开更多
关键词 semi-solid slurry annular electromagnetic stirring rheocast A356 aluminum alloy microstructural evolution mechanical properties magnetic flux density
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Microstructure characteristics and thermodynamic properties of A357-SiCp/A357 layered composites prepared by semi-solid vacuum stirring suction casting
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作者 Zhen-lin Zhang Ying Xiao +3 位作者 Jun Xu Feng-liang Tan Li Wang Min He 《China Foundry》 SCIE CAS CSCD 2023年第2期108-114,共7页
A357-SiCp/A357 layered composites were prepared using a semi-solid vacuum stirring suction casting method.The microstructures,mechanical properties,and thermal conductivities of the composites fabricated under differe... A357-SiCp/A357 layered composites were prepared using a semi-solid vacuum stirring suction casting method.The microstructures,mechanical properties,and thermal conductivities of the composites fabricated under different suction casting processes were compared.Additionally,the microstructural evolution characteristics and performance enhancement mechanism of the A357-SiCp/A357 layered composites were discussed.The results demonstrate that suction casting at 610°C with a low solid phase ratio can significantly enhance the material density and reduce the agglomeration of SiCp.The A357-SiC_(p)/A357 interface is clear and straight with good bonding.With an increase in the suction casting temperature,the bending resistance and thermal conductivity of the A357-SiC_(p)/A357 layered composites exhibit a trend of significantly increase at first and then slowly decrease owing to casting defects,interface bonding,and SiCp distribution.Compared with SiCp/A357 composites,the bending strength,deflection,and thermal conductivity of the A357-SiCp/A357 layered composites increase from 257 MPa,1.07 mm,and 155.72 W·(m·K)^(-1) to 298 MPa,2.1 mm,and 169.86 W·(m·K)^(-1),respectively.This study provides a reference for improving the rheological casting of aluminum matrix layered composites. 展开更多
关键词 SEMI-SOLID vacuum stirring suction casting SiCp/A357 layered composites thermodynamic properties rheological casting
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Development and Research of Non⁃Stirring Conveying Device for Waste Resin in Nuclear Power Plant
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作者 Jianfa Li Yongzhen Hua +2 位作者 Mingmei Liu Rui Zhang Taishan Lou 《Journal of Harbin Institute of Technology(New Series)》 CAS 2023年第3期45-59,共15页
Blockage in the storage and transportation of waste resin is a difficult problem in the radioactive waste treatment process of nuclear power plants.In this study,in order to solve the problems of unstable resin transp... Blockage in the storage and transportation of waste resin is a difficult problem in the radioactive waste treatment process of nuclear power plants.In this study,in order to solve the problems of unstable resin transport concentration and easy blockage of conveying equipment and pipelines in nuclear power plants in China,a set of non⁃stirring conveying devices is developed,and theoretical calculations,simulation analysis and experimental verification are carried out.By transporting resin using the no stirring conveying device developed in this paper,it is not only to eliminate the risk of blockage and ensure the safety of transportation,but also to adjust the concentration of conveying resin to change the transport efficiency according to the operating conditions.The effective bearing rate of waste resin storage tank can be improved,so that the comprehensive performance of waste resin storage and transportation in nuclear power plants can be greatly improved. 展开更多
关键词 nuclear power plant ion exchange resin TRANSPORTATION no stirring device no blockage
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3D MERGE与3D SPACE STIR序列在腰椎间盘突出症检查中的应用比较 被引量:1
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作者 李兰 殷小丹 +2 位作者 李旭雪 吴海燕 张滔 《中国医学物理学杂志》 CSCD 2024年第1期27-31,共5页
目的:对比三维多回波恢复梯度回波(3D MERGE)、三维可变反转角快速自旋回波(3D SPACE STIR)序列在腰椎间盘突出症(LDH)检查中的应用效果。方法:选择2020年1月~2022年11月收治的135例LDH患者,回顾性分析患者临床和磁共振成像(MRI)资料,... 目的:对比三维多回波恢复梯度回波(3D MERGE)、三维可变反转角快速自旋回波(3D SPACE STIR)序列在腰椎间盘突出症(LDH)检查中的应用效果。方法:选择2020年1月~2022年11月收治的135例LDH患者,回顾性分析患者临床和磁共振成像(MRI)资料,所有患者均接受常规MRI扫描及3D MERGE、3D SPACE STIR序列扫描,对比3D MERGE、3D SPACE STIR序列测量神经根直径的一致性,评价两种序列的图像质量参数[信噪比(SNR)、对比噪声比(CNR)]、图像清晰度评分。结果:3D MERGE和3D SPACE STIR序列测量的L3~S1神经根直径比较差异无统计学意义(P>0.05),且两组序列测量的L3、L4、L5和S1直径均显示出较高相关性(r=0.957,0.986,0.975,0.972,P<0.05);3D MERGE序列的SNR及CNR均高于3D SPACE STIR序列,神经根显示分级、图像清晰度评分优于3D SPACE STIR序列,差异有统计学意义(P<0.05)。结论:3D MERGE、3D SPACE STIR序列在LDH神经根直径测量中具有极高一致性,3D MERGE序列较3D SPACE STIR序列能够更清晰显示神经跟的解剖形态,图像质量更好。 展开更多
关键词 腰椎间盘突出症 3D MERGE 3D SPACE STIR 神经根直径 图像质量
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Mechanism of microarc oxidation on AZ91D Mg alloy induced byβ-Mg_(17)Al_(12) phase 被引量:1
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作者 Dajun Zhai Xiaoping Li Jun Shen 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第4期712-724,共13页
This work proposed a strategy of indirectly inducing uniform microarc discharge by controlling the content and distribution ofβ-Mg_(17)Al_(12)phase in AZ91D Mg alloy.Two kinds of nano-particles(ZrO_(2)and TiO_(2))wer... This work proposed a strategy of indirectly inducing uniform microarc discharge by controlling the content and distribution ofβ-Mg_(17)Al_(12)phase in AZ91D Mg alloy.Two kinds of nano-particles(ZrO_(2)and TiO_(2))were designed to be added into the substrate of Mg alloy by friction stir processing(FSP).Then,Mg alloy sample designed with different precipitated morphology ofβ-Mg_(17)Al_(12)phase was treated by microarc oxidation(MAO)in Na_(3)PO_(4)/Na2SiO3electrolyte.The characteristics and performance of the MAO coating was analyzed using scanning electron microscopy(SEM),energy dispersive spectrometer(EDS),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),contact angle meter,and potentiodynamic polarization.It was found that the coarseα-Mg grains in extruded AZ91D Mg alloy were refined by FSP,and theβ-Mg_(17)Al_(12)phase with reticular structure was broken and dispersed.The nano-ZrO_(2)particles were pinned at the grain boundary by FSP,which refined theα-Mg grain and promoted the precipitation ofβ-Mg_(17)Al_(12)phase in grains.It effectively inhibited the“cascade”phenomenon of microarcs,which induced the uniform distribution of discharge pores.The MAO coating on Zr-FSP sample had good wettability and corrosion resistance.However,TiO_(2)particles were hardly detected in the coating on TiFSP sample. 展开更多
关键词 AZ91D Mg alloy microarc oxidation friction stir processing ZrO_(2) TiO_(2) β-Mg_(17)Al_(12)
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Effect of aspect ratio of elliptical stirred vessel on mixing time and flow field characteristics in the absence of baffles
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作者 Yuan Yao Peiqiao Liu +5 位作者 Qian Zhang Zequan Li Benjun Xi Changyuan Tao Yundong Wang Zuohua Liu 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第1期63-74,共12页
Elliptical tanks were used as an alternative to circular tanks in order to improve mixing efficiency and reduce mixing time in unbaffled stirred tanks(USTs). Five different aspect ratios of elliptical vessels were des... Elliptical tanks were used as an alternative to circular tanks in order to improve mixing efficiency and reduce mixing time in unbaffled stirred tanks(USTs). Five different aspect ratios of elliptical vessels were designed to compare their mixing time and flow field. Computational fluid dynamics(CFD) simulations were performed using the k–ε model to calculate the mixing time and simulate turbulent flow field features, such as streamline shape, velocity distribution, vortex core region distribution, and turbulent kinetic energy(TKE) transfer. Visualization was also carried out to track the tinctorial evolution of the liquid phase. Results reveal that elliptical stirred tanks can significantly improve mixing performance in USTs. Specifically, the mixing time at an aspect ratio of 2.00 is only 45.3% of the one of a circular stirred tank. Furthermore, the secondary flow is strengthened and the vortex core region increases with the increase of aspect ratio. The axial velocity is more sensitive to the aspect ratio than the circumferential and radial velocity. Additionally, the TKE transfer in elliptical vessels is altered. These findings suggest that elliptical vessels offer a promising alternative to circular vessels for enhancing mixing performance in USTs. 展开更多
关键词 Mixing time CFD Stirred tank Secondary flow Mixing performance
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Improvement of Microstructure and Mechanical Properties of Rapid Cooling Friction Stir-welded A1050 Pure Aluminum
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作者 许楠 LIU Lutao +2 位作者 SONG Qining ZHAO Jianhua BAO Yefeng 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第1期134-141,共8页
Two-mm thick A1050 pure aluminum plates were successfully joined by conventional and rapid cooling friction stir welding(FSW), respectively. The microstructure and mechanical properties of the welded joints were inves... Two-mm thick A1050 pure aluminum plates were successfully joined by conventional and rapid cooling friction stir welding(FSW), respectively. The microstructure and mechanical properties of the welded joints were investigated by electron backscatter diffraction characterization, Vickers hardness measurements, and tensile testing. The results showed that liquid CO_(2) coolant significantly reduced the peak temperature and increased the cooling rate, so the rapidly cooled FSW joint exhibited fine grains with a large number of dislocations. The grain refinement mechanism of the FSW A1050 pure aluminum joint was primarily attributed to the combined effects of continuous dynamic recrystallization, grain subdivision, and geometric dynamic recrystallization. Compared with conventional FSW, the yield strength, ultimate tensile strength, and fracture elongation of rapidly cooled FSW joint were significantly enhanced, and the welding efficiency was increased from 80% to 93%. The enhanced mechanical properties and improved synergy of strength and ductility were obtained due to the increased dislocation density and remarkable grain refinement. The wear of the tool can produce several WC particles retained in the joint, and the contribution of second phase strengthening to the enhanced strength should not be ignored. 展开更多
关键词 aluminum alloy friction stir welding RECRYSTALLIZATION microstructure mechanical properties
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Effects of friction stir processing and nano-hydroxyapatite on the microstructure,hardness,degradation rate and in-vitro bioactivity of WE43 alloy for biomedical applications
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作者 Bo Wu Farazila Yusof +5 位作者 Fuguo Li Huan Miao A.R.Bushroa Mohd Ridha Bin Muhamad Irfan Anjum Badruddin Mahmoud Z.Ibrahim 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第1期209-224,共16页
Nowadays,magnesium alloys are emerging in biomedical implants for their similar properties to natural bones.However,the rapid degradation of magnesium alloys in biological media hinders successful implantation.Refinem... Nowadays,magnesium alloys are emerging in biomedical implants for their similar properties to natural bones.However,the rapid degradation of magnesium alloys in biological media hinders successful implantation.Refinement of microstructure,as well as reinforcement particles can significantly improve the degradation rate.In this work,multi-pass friction stir processing(FSP)was proposed to synthesize WE43/nano-hydroxyapatite(n HA)surface composite,the microstructure,reinforced particle distribution,micro-hardness,corrosion behavior and in-vitro bioactivity were studied.The subsequent FSP passes of WE43 alloy and WE43/n HA composite refined the grain size which was reduced by 94.29%and 95.92%(2.63 and 1.88μm,respectively)compared to base metal after three passes.This resulted in increasing the microhardness by 120%(90.86 HV0.1)and 135%(105.59 HV0.1)for the WE43 and WE43-n HA,respectively.It is found that increasing FSP passes improved the uniform distribution of n HA particles within the composite matrix which led to improved corrosion resistance and less degradation rate.The corrosion rate of the FSPed WE43/n HA composite after three passes was reduced by 38.2%(4.13 mm/year)and the degradation rate was reduced by 69.7%(2.87 mm/y).This is attributed to secondary phase(Mg24Y5and Mg41Nd5)particle fragmentation and redistribution,as well as a homogeneous distribution of n HA.Additionally,the growing Ca-P and Mg(OH)2layer formed on the surface represented a protective layer that reduced the degradation rate.The wettability test revealed a relatively hydrophilic surface with water contact angle of 49.1±2.2°compared to 71.2±2.1°for base metal.Also,biomineralization test showed that apatite layer grew after immersion 7d in simulated body fluid with atomic ratio of Ca/P 1.60 approaching the stoichiometric ratio(1.67)indicating superior bioactivity of FSPed WE43/n HA composite after three passes.These results raise that the grain refinement by FSP and introduction of n HA particles significantly improved the degradation rate and in-vitro bioactivity of WE43 alloy for biomedical applications. 展开更多
关键词 Friction stir processing Magnesium-based composite NANO-HYDROXYAPATITE Corrosion behavior In-vitro bioactivity
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Exploring a balance between strength and ductility of hexagonal BN nanoplatelet reinforced ZK61 magnesium composite
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作者 Kewei Zhang Xiaolong Lu +2 位作者 Yufeng Sun Shaokang Guan Yao Chen 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第5期1899-1910,共12页
The practical applications of magnesium(Mg)alloys are usually beset by their relatively low strength and limited ductility.Herein we attempt to fabricate hexagonal BN nanoplatelet(BNNP)reinforced ZK61 magnesium compos... The practical applications of magnesium(Mg)alloys are usually beset by their relatively low strength and limited ductility.Herein we attempt to fabricate hexagonal BN nanoplatelet(BNNP)reinforced ZK61 magnesium composites using a combination of spark plasma sintering and friction stir processing.The resulting composites exhibit microstructural characteristics of homogeneous dispersion of BNNP in Mg matrix with refined equiaxed grains and(0002)basal texture roughly surrounding the pin column surface.Transmission electron microscopy observation illustrates that trace amounts of Mg_(3)N_(2)and MgB_(2)form at BNNP-Mg interface,in which Mg_(3)N_(2)locates at the basal plane of a BNNP and MgB_(2)grows at its open edge.The spatial distribution of Mg_(3)N_(2)and MgB_(2)facilitates interfacial wetting and stronger BNNP-Mg interface in such a way that interfacial products act as anchors bonding between them.In comparison with monolithic ZK61 alloy,the BNNP/ZK61 composites display simultaneous improvements in yield strength,hardness and ductility,achieving good strength-ductility balance.This research is expected to shed some light on BNNP potentials for designing and producing magnesium composites with high strength and good ductility. 展开更多
关键词 BN nanoplatelet Magnesium composite STRENGTH DUCTILITY Spark plasma sintering Friction stir processing
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Application of the CatBoost Model for Stirred Reactor State Monitoring Based on Vibration Signals
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作者 Xukai Ren Huanwei Yu +3 位作者 Xianfeng Chen Yantong Tang Guobiao Wang Xiyong Du 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第7期647-663,共17页
Stirred reactors are key equipment in production,and unpredictable failures will result in significant economic losses and safety issues.Therefore,it is necessary to monitor its health state.To achieve this goal,in th... Stirred reactors are key equipment in production,and unpredictable failures will result in significant economic losses and safety issues.Therefore,it is necessary to monitor its health state.To achieve this goal,in this study,five states of the stirred reactor were firstly preset:normal,shaft bending,blade eccentricity,bearing wear,and bolt looseness.Vibration signals along x,y and z axes were collected and analyzed in both the time domain and frequency domain.Secondly,93 statistical features were extracted and evaluated by ReliefF,Maximal Information Coefficient(MIC)and XGBoost.The above evaluation results were then fused by D-S evidence theory to extract the final 16 features that are most relevant to the state of the stirred reactor.Finally,the CatBoost algorithm was introduced to establish the stirred reactor health monitoring model.The validation results showed that the model achieves 100%accuracy in detecting the fault/normal state of the stirred reactor and 98%accuracy in diagnosing the type of fault. 展开更多
关键词 Stirred reactor fault diagnosis vibration signal CatBoost
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Research progress in friction stir processing of magnesium alloys and their metal matrix surface composites: Evolution in the 21^(st )century
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作者 Roshan Vijay Marode Tamiru Alemu Lemma +3 位作者 Nabihah Sallih Srinivasa Rao Pedapati Mokhtar Awang Adeel Hassan 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第6期2091-2146,共56页
Rising concerns about climate change drive the demand for lightweight components.Magnesium(Mg)alloys are highly valued for their low weight,making them increasingly important in various industries.Researchers focusing... Rising concerns about climate change drive the demand for lightweight components.Magnesium(Mg)alloys are highly valued for their low weight,making them increasingly important in various industries.Researchers focusing on enhancing the characteristics of Mg alloys and developing their Metal Matrix Composites(MMCs)have gained significant attention worldwide over the past decade,driven by the global shift towards lightweight materials.Friction Stir Processing(FSP)has emerged as a promising technique to enhance the properties of Mg alloys and produce Mg-MMCs.Initially,FSP adapted to refine grain size from the micro to the nano level and accelerated the development of MMCs due to its solid-state nature and the synergistic effects of microstructure refinement and reinforcement,improving strength,hardness,ductility,wear resistance,corrosion resistance,and fatigue strength.However,producing defect-free and sound FSPed Mg and Mg-MMCs requires addressing several variables and their interdependencies,which opens up a broad range of practical applications.Despite existing reviews on individual FSP of Mg,its alloys,and MMCs,an attempt has been made to analyze the latest research on these three aspects collectively to enhance the understanding,application,and effectiveness of FSP for Mg and its derivatives.This review article discusses the literature,classifies the importance of Mg alloys,provides a historical background,and explores developments and potential applications of FSPed Mg alloys.It focuses on novel fabrication methods,reinforcement strategies,machine and tool design parameters,material characterization,and integration with other methods for enhanced properties.The influence of process parameters and the emergence of defects are examined,along with specific applications in mono and hybrid composites and their microstructure evolution.The study identifies promising reinforcement materials and highlights research gaps in FSP for Mg alloys and MMCs production.It concludes with significant recommendations for further exploration,reflecting ongoing advancements in this field. 展开更多
关键词 Magnesium alloys Friction stir processing Metal matrix composites LIGHTWEIGHT Surface modification
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Preheating-assisted solid-state friction stir repair of Al-Mg-Si alloy plate at different rotational speeds
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作者 Hui Wang Yidi Li +3 位作者 Ming Zhang Wei Gong Ruilin Lai Yunping Li 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第4期725-736,共12页
Additive friction stir deposition(AFSD)is a novel structural repair and manufacturing technology has become a research hotspot at home and abroad in the past five years.In this work,the microstructural evolution and m... Additive friction stir deposition(AFSD)is a novel structural repair and manufacturing technology has become a research hotspot at home and abroad in the past five years.In this work,the microstructural evolution and mechanical performance of the Al-Mg-Si alloy plate repaired by the preheating-assisted AFSD process were investigated.To evaluate the tool rotation speed and substrate preheating for repair quality,the AFSD technique was used to additively repair 5 mm depth blind holes on 6061 aluminum alloy substrates.The results showed that preheat-assisted AFSD repair significantly improved joint bonding and joint strength compared to the control non-preheat substrate condition.Moreover,increasing rotation speed was also beneficial to improve the metallurgical bonding of the interface and avoid volume defects.Under preheating conditions,the UTS and elongation were positively correlated with rotation speed.Under the process parameters of preheated substrate and tool rotation speed of 1000 r/min,defect-free specimens could be obtained accompanied by tensile fracture occurring in the substrate rather than the repaired zone.The UTS and elongation reached the maximum values of 164.2MPa and 13.4%,which are equivalent to 99.4%and 140%of the heated substrate,respectively. 展开更多
关键词 additive friction stir deposition structural repair tool rotation speed Al alloy
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Tailoring the microstructure of Mg-Al-Sn-RE alloy via friction stir processing and the impact on its electrochemical discharge behaviour as the anode for Mg-air battery
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作者 Jingjing Liu Hao Hu +4 位作者 Tianqi Wu Jinpeng Chen Xusheng Yang Naiguang Wang Zhicong Shi 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第4期1554-1565,共12页
Constructing the magnesium alloy with fine grains,low density of dislocations,and weak crystal orientation is of crucial importance to enhance its comprehensive performance as the anode for Mg-air battery.However,this... Constructing the magnesium alloy with fine grains,low density of dislocations,and weak crystal orientation is of crucial importance to enhance its comprehensive performance as the anode for Mg-air battery.However,this unique microstructure can hardly be achieved with conventional plastic deformation such as rolling or extrusion.Herein,we tailor the microstructure of Mg-Al-Sn-RE alloy by using the friction stir processing,which obviously refines the grains without increasing dislocation density or strengthening crystal orientation.The Mg-air battery with the processed Mg-Al-Sn-RE alloy as the anode exhibits higher discharge voltages and capacities than that employing the untreated anode.Furthermore,the impact of friction stir processing on the electrochemical discharge behaviour of Mg-Al-Sn-RE anode and the corresponding mechanism are also analysed according to microstructure characterization and electrochemical response. 展开更多
关键词 Magnesium anode Electrochemical discharge behaviour Mg-air battery Friction stir processing
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Prediction of corrosion rate for friction stir processed WE43 alloy by combining PSO-based virtual sample generation and machine learning
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作者 Annayath Maqbool Abdul Khalad Noor Zaman Khan 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第4期1518-1528,共11页
The corrosion rate is a crucial factor that impacts the longevity of materials in different applications.After undergoing friction stir processing(FSP),the refined grain structure leads to a notable decrease in corros... The corrosion rate is a crucial factor that impacts the longevity of materials in different applications.After undergoing friction stir processing(FSP),the refined grain structure leads to a notable decrease in corrosion rate.However,a better understanding of the correlation between the FSP process parameters and the corrosion rate is still lacking.The current study used machine learning to establish the relationship between the corrosion rate and FSP process parameters(rotational speed,traverse speed,and shoulder diameter)for WE43 alloy.The Taguchi L27 design of experiments was used for the experimental analysis.In addition,synthetic data was generated using particle swarm optimization for virtual sample generation(VSG).The application of VSG has led to an increase in the prediction accuracy of machine learning models.A sensitivity analysis was performed using Shapley Additive Explanations to determine the key factors affecting the corrosion rate.The shoulder diameter had a significant impact in comparison to the traverse speed.A graphical user interface(GUI)has been created to predict the corrosion rate using the identified factors.This study focuses on the WE43 alloy,but its findings can also be used to predict the corrosion rate of other magnesium alloys. 展开更多
关键词 Corrosion rate Friction stir processing Virtual sample generation Particle swarm optimization Machine learning Graphical user interface
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Effect of thermo-mechanical conditions during constrained friction processing on the particle refinement of AM50 Mg-alloy phases
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作者 Camila Caroline de Castro AndréMartins Neves Benjamin Klusemann 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第6期2298-2311,共14页
Constrained Friction Processing(CFP)is a novel solid-state processing technique suitable for lightweight materials,such Mg-and Al-alloys.The technique enables grain size refinement to fine or even ultrafine scale.In t... Constrained Friction Processing(CFP)is a novel solid-state processing technique suitable for lightweight materials,such Mg-and Al-alloys.The technique enables grain size refinement to fine or even ultrafine scale.In this study,the effect of CFP on the microstructural refinement of AM50 rods is investigated in terms of particle size and morphology of the eutectic and secondary phases originally present in the base material,in particular the eutecticβ-Mg_(17)Al_(12)and Al-Mn phases.For that purpose,as-cast and solution heat-treated base material and processed samples were analyzed.The Al8Mn5 intermetallic phase was identified as the main secondary phase present in all samples before and after the processing.A notorious refinement of these particles was observed,starting from particles with an average equivalent length of a few micrometers to around 560 nm after the processing.The refinement of the secondary phase refinement is attributed to a mechanism analogous to the attrition comminution,where the combination of temperature increase and shearing of the material enables the continuous breaking of the brittle intermetallic particles into smaller pieces.As for the eutectic phase,the results indicate the presence of the partially divorcedβ-Mg_(17)Al_(12)particles exclusively in the as-cast base material,indicating that no further phase transformations regarding the eutectic phase,such as dynamic precipitation,occurred after the CFP.In the case of the processed as-cast material analyzed after the CFP,the thermal energy generated during the processing led to temperature values above the solvus limit of the eutectic phase,which associated with the mechanical breakage of the particles,enabled the complete dissolution of this phase.Therefore,CFP was successfully demonstrated to promote an extensive microstructure refinement in multiple aspects,in terms of grain sizes of theα-Mg phase and presence and morphology of the Al-Mn and eutecticβ-Mg_(17)Al_(12). 展开更多
关键词 Constrained friction processing AM50 Refill friction stir spot welding Extrusion β-Mg_(17)Al_(12) Al-Mn phases
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Effect of Butternut Squash (Cucurbita moschata) Seed Powder on the Chemical and Rheological Properties of Stirred Cultured Camel Milk and Yoghurt
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作者 Collins K. Kangogo Patrick S. Muliro Joseph O. Anyango 《Food and Nutrition Sciences》 CAS 2024年第7期576-593,共18页
Research shows that producing fermented camel milk is hard because of the milk’s inability to form a firm coagulum, attributed to low levels of κ-casein and ꞵ-lactoglobulin and the large casein micelle size, leading... Research shows that producing fermented camel milk is hard because of the milk’s inability to form a firm coagulum, attributed to low levels of κ-casein and ꞵ-lactoglobulin and the large casein micelle size, leading to a weak network of casein formation. In an effort to address this issue, researchers turned to corn starch as a thickening agent, discovering that a concentration of 2.0% effectively improved the viscosity and significantly reduced syneresis in stirred camel milk yoghurt and cultured camel milk. This study explores alternatives to corn starch, focusing on butternut squash seeds as a promising substitute due to their hydrocolloid composition. By incorporating butternut squash (Cucurbita moschata) seed powder (BSSP) as a thickening agent, this study aimed at enhancing the chemical and rheological properties of stirred camel milk yoghurt and cultured camel milk. Fermented camel milk was prepared using 4 litres of camel milk, 2% starter cultures (thermophilic culture for yoghurt and mesophilic aromatic culture for stirred cultured camel milk) and BSSP 0.0% (negative control), 0.4%, 0.8%, 1.2%, 1.6%, 2.0% mixed with 0.4% gelatin. 2.0% corn starch mixed with 0.4% gelatin was used as a standard for comparison. Results showed that increasing the BSSP level significantly (p < 0.05) decreased the moisture content while increasing the total solid content of stirred fermented camel milk products. There was an increase in ash content with an increase in BSSP levels. There was a significant (p < 0.05) reduction in the pH, with an increase in BSSP levels in stirred fermented camel milk samples. Increasing the concentration of BSSP from 0.4% to 2.0% resulted in a significant (p < 0.05) increase in viscosity and a reduction in syneresis of stirred camel milk yoghurt and stirred cultured camel milk samples. This study demonstrated that BSSP effectively enhances the viscosity, reduces syneresis and increases acidity in stirred fermented camel milk products during storage. 展开更多
关键词 Corn Starch Butternut Squash Seed Powder GELATIN Stirred Camel Milk Yoghurt Stirred Cultured Camel Milk
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Microstructure and mechanical properties of stationary shoulder friction stir welding joint of 2A14-T62 aluminum alloy
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作者 邓建峰 王博 +3 位作者 王生希 郭伟强 黄智恒 费文潘 《China Welding》 CAS 2024年第2期31-38,共8页
2A14-T62 butt joint was successfully welded by stationary shoulder friction stir welding(SSFSW)method.The results showed that using a pin with small shoulder could broaden the process window,and under a rotation speed... 2A14-T62 butt joint was successfully welded by stationary shoulder friction stir welding(SSFSW)method.The results showed that using a pin with small shoulder could broaden the process window,and under a rotation speed of 2000 r/min and welding speed of 30 mm/min,joint with smooth surface,small reduction in thickness and little inner defects was obtained.The weld nugget zone was approx-imately circular,which was a unique morphology for SSFSW.The heat-affected zone(HAZ)and thermo-mechanically affected zone(TMAZ)were both quite narrow due to the lower heat input and slight mechanical action of the stationary shoulder.The fraction of high angle grain boundaries(HAGBs)exhibited a“W”shape along horizontal direction(from advancing side to retreating side),and the minim-um value located at HAZ.The average ultimate tensile strength and elongation of the joint were 325 MPa and 4.5%,respectively,with the joint efficiency of 68.3%.The joint was ductile fractured and the fracture surface contained two types of dimples morphology in different re-gions of the joint.Microhardness distribution in the joint exhibited a“W”shape,and the difference along the thickness direction was negli-gible.The joint had strong stress corrosion cracking susceptibility,and the slow stain rate tensile strength was 139 MPa.Microcrack and Al2O3 particulates were observed at the fracture surface. 展开更多
关键词 2A14-T62 aluminum alloy stationary shoulder friction stir welding microstructure mechanical property stress corrosion cracking
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TUNING INTO UYGUR TRADITION Xinjiang Muqam melodies resonate through the corridors of time
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作者 Li Fangfang Wang Zhiwei 《China Report ASEAN》 2024年第4期54-55,共2页
As dawn breaks over the ancient Silk Road lands of China’s Xinjiang Uygur Autonomous Region,Dilixiati Parhati is gearing up for yet another busy day.He juggles multiple roles:musician,scholar,leader of a Muqam art tr... As dawn breaks over the ancient Silk Road lands of China’s Xinjiang Uygur Autonomous Region,Dilixiati Parhati is gearing up for yet another busy day.He juggles multiple roles:musician,scholar,leader of a Muqam art troupe and,most recently,a voice in China’s National People’s Congress(NPC)-the country’s top legislature.In all these roles,safeguarding the soul-stirring music of Uygur Muqam,often dubbed“the mother of Uygur music,”for future generations is his mission. 展开更多
关键词 mother XINJIANG stirring
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