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Distribution pattern of acoustic and streaming field during multi-source ultrasonic melt treatment process

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中国铸造:英文版 2023年第5期20卷 452-460页

作者： Xiao-gang Fang Qi Wei Tian-yang Zhang Ji-guang liu You-wen Yang shu-lin lü shu-sen Wu Yi-qing Chen School of Materials Science and Engineering Hefei University of TechnologyHefei 230009China Engineering Research Center of High-Performance Copper Alloy Materials and Processing Ministry of EducationHefei 230009China State Key laboratory of Material Processing and Die&Mould Technology Huazhong University of Science and TechnologyWuhan 430074China

The ultrasonic melt treatment(UMT)is widely used in the fields of casting and metallurgy.However,there are certain drawbacks associated with the conventional process of single-source ultrasonic(SSU)treatment,such as the fast attenuation of energy and limited range of effectiveness.In this study,the propagation models of SSU and four-source ultrasonic(FSU)in Al melt were respectively established,and the distribution patterns of acoustic and streaming field during the ultrasonic treatment process were investigated by numerical simulation and physical experiments.The simulated results show that the effective cavitation zone is mainly located in a small spherical region surrounding the end of ultrasonic horn during the SSU treatment process.When the FSU is applied,the effective cavitation zone is obviously expanded in the melt.It increases at first and then decreases with increasing the vibration-source spacing(lv)from 30 mm to 100 mm.Especially,when the lv is 80 mm,the area of effective cavitation zone reaches the largest,indicating the best effect of cavitation.Moreover,the acoustic streaming level and flow pattern in the melt also change with the increase of lv.When the lv is 80 mm,both the average flow rate and maximum flow rate of the melt reach the highest,and the flow structure is more stable and uniform,with the typical morphological characteristics of angular vortex,thus significantly expanding the range of acoustic streaming.The accuracy of the simulation results was verified by physical experiments of glycerol aqueous solution and tracer particles.

关键词： four-source ultrasound acoustic cavitation streaming field vibration-source spacing

Effects of high-pressure rheo-squeeze casting on the Fe-rich phases and mechanical properties of Al-17Si-(1,1.5)Fe alloys

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International Journal of Minerals,Metallurgy and Materials 2018年第9期25卷 1018-1026页

作者： Chong lin shu-sen Wu shu-lin lü Ping An He-bao Wu State Key laboratory of Materials Processing and Die & Mould Technology Huazhong University of Science and Technology Hubei Provincial Key laboratory of Chemical Equipment Intensification and Intrinsic Safety Wuhan Institute of Technology

The effects of high pressure rheo-squeeze casting(HPRC) on the Fe-rich phases(FRPs) and mechanical properties of Al-17 Si-(1,1.5)Fe alloys were investigated. The alloy melts were first treated by ultrasonic vibration(UV) and then formed by high-pressure squeeze casting(HPSC). The FRPs in the as-cast HPSC Al-17 Si-1 Fe alloys only contained a long, needle-shaped β-Al5 Fe Si phase at 0 MPa. In addition to the β-Al5 Fe Si phase, the HPSC Al-17 Si-1.5 Fe alloy also contained the plate-shaped δ-Al4 Fe Si2 phase. A fine, block-shaped δ-Al4 Fe Si2 phase was formed in the Al-17 Si-1 Fe alloy treated by UV. The size of FRPs decreased with increasing pressure. After UV treatment, solidification under pressure led to further refinement of the FRPs. Considering alloy samples of the same composition, the ultimate tensile strength(UTS) of the HPRC samples was higher than that of the HPSC samples, and the UTS increased with increasing pressure. The UTS of the Al-17 Si-1 Fe alloy formed by HPSC exceeded that of the Al-17 Si-1.5 Fe alloy formed in the same manner under the same pressure. Conversely, the UTS of the Al-17 Si-1 Fe alloy formed by HPRC decreased to a value lower than that of the Al-17 Si-1.5 Fe alloy formed in the same manner.

关键词： high pressure rheo-squeeze casting Al-17Si-(1,1.5)Fe alloys Fe-rich phases mechanical properties

Microstructure and mechanical properties of a cast heat-resistant rare-earth magnesium alloy

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China Foundry 2023年第4期20卷 289-298页

作者： Xiao-ping Zhu Jun-qing Yao Hai-long Wu Xin-wang liu Hua liu Zi-tian Fan shu-lin lü Kai Wang Zi-dong Wang School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China State Key laboratory of Materials Processing and Die&Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China Dekai Intelligent Casting Co. Ltd.Zhuozhou 072750HebeiChina China Iron and Steel Research Institute Group Beijing 100081China Guangdong Hongtu Wuhan Die-casting Co. Ltd.Wuhan 430207China

Microstructure,mechanical properties and phase transformation of a heat-resistant rare-earth(RE)Mg-16.1Gd-3.5Nd-0.38Zn-0.26Zr-0.15Y(wt.%)alloy were investigated.The as-cast alloy is composed of equiaxedα-Mg matrix,net-shaped Mg5RE and Zr-rich phases.According to aging hardening curves and tensile properties variation,the optimized condition of solution treatment at 520℃for 8 h and subsequent aging at 204℃for 12 h was selected.The continuous secondary Mg5RE phase predominantly formed at grain boundaries during solidification transforms to residual discontinuousβ-Mg5RE phase and fine cuboid REH2particles after heat treatment.The annealed alloy exhibits good comprehensive tensile property at 350℃,with ultimate tensile strength of 153 MPa and elongation to fracture of 6.9%.Segregation of RE elements and eventually RE-rich precipitation at grain boundaries are responsible for the high strength at elevated temperature.

关键词： heat-resistant magnesium alloy rare earth microstructure phase transformation tensile property strengthening

深冷循环热处理下锆基金属玻璃的回春行为调控

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Transactions of Nonferrous Metals Society of China 2024年第2期34卷 582-591页

作者：郭威余圣丁俊吕书林吴树森赵觅华中科技大学材料科学与工程学院材料成形与模具技术全国重点实验室武汉430074 深圳华中科技大学研究院深圳518057 西安交通大学金属材料强度国家重点实验室材料创新设计中心西安710049 华中科技大学航空航天学院武汉430074

研究Zr_(55)Cu_(30)Ni_(5)Al_(10)(摩尔分数,%)金属玻璃在深冷循环处理过程中的回春行为。实验发现,随着循环次数的增加,样品的回春程度更高,表现为更高的弛豫焓与更低的密度。回春程度经200次循环后逐渐饱和,这可能与非晶结构中有限的... 详细信息

研究Zr_(55)Cu_(30)Ni_(5)Al_(10)(摩尔分数,%)金属玻璃在深冷循环处理过程中的回春行为。实验发现,随着循环次数的增加,样品的回春程度更高,表现为更高的弛豫焓与更低的密度。回春程度经200次循环后逐渐饱和,这可能与非晶结构中有限的自由体积含量有关。同时,高循环次数下的样品硬度更低,塑性更好,这与其剪切转变区体积增大有关。此时,更低的剪切面形成能有利于多重剪切带的形成。此外,还发现自由体积含量与样品塑性应变及剪切转变区体积呈线性关系。分子动力学模拟结果还表明,在高冷速下回春程度高的样品会发生原子体积的饱和。

关键词：金属玻璃回春深冷循环热处理循环次数塑性

Effects of heat treatment on microstructure evolution and mechanical properties of Mg-6Zn-1.4Y-0.6Zr alloy

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China Foundry 2017年第3期14卷 199-204页

作者： Jing Wang Xiao-gang Fang shu-sen Wu shu-lin lü State Key lab of Materials Processing and Die & Mould Technology Huazhong University of Science and Technology Wuhan 430074 China

To investigate the effects of solution temperature and the decomposition of I-phase on the microstructure, phase composition and mechanical properties of as-cast Mg-6Zn-1.4Y-0.6Zr alloy, solution treatment at 440 oC, 460 oC and 480 oC and further aging treatment were conducted on the alloy. The results indicate that the net-like intermetallic compounds(mainly I-phase) dissolve into the α-Mg matrix gradually with the increase of solution temperature from 440 oC to 480 oC. Besides, the I-phase decomposes completely at 480 oC, with the formation of fine W-phase(thermal stable phase) and Mg_7Zn_3 phase. In addition, a great number of fine and dispersive Mg-Zn binary phases precipitate in the α-Mg matrix during the aging treatment. Due to the increase of solute atoms and the precipitation of strengthening phases, such as W-phase and Mg-Zn phases, the optimal strength is obtained after solution treatment at 460 oC for 8 h and aged at 200 oC for 16 h. The yield strength(YS), ultimate tensile strength(UTS) and elongation are 208 MPa, 257 MPa and 3.8%, respectively. Compared with the as-cast alloy, the increments of YS and UTS are 117% and 58%, respectively, while the decrement of elongation is 46%.

关键词：镁合金加热处理微观结构机械性质 TG146.22 A

Nano-SiC_P particles distribution and mechanical properties of Al-matrix composites prepared by stir casting and ultrasonic treatment

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China Foundry 2018年第3期15卷 203-209页

作者： shu-sen Wu Du Yuan shu-lin lü Kun Hu Ping An State Key lab of Materials Processing and Die & Mould Technology Huazhong University of Science and Technology

Nano-ceramic particles are generally difficult to add into molten metal because of poor wettability. Nano-SiC_Particles reinforced A356 aluminum alloy composites were prepared by a new complex process, i.e., a molten-metal process combined with high energy ball milling and ultrasonic vibration methods. The nano particles were β-SiC_P with an average diameter of 40 nm, and pre-oxidized at about 850 °C to form an oxide layer with a thickness of approximately 3 nm. The mm-sized composite granules containing nano-SiC_P were fi rstly produced by milling the mixture of oxidized nano-SiC_P and pure Al powders, and then were remelted in the matrix-metal melt with mechanical stirring and treated by ultrasonic vibration to prepare the composite. SEM analysis results show that the nano-SiC_P articles are distributed uniformly in the matrix and no serious agglomeration is observed. The tensile strength and elongation of the composite with 2 wt.% nano-SiC_P in as-cast state are 226 MPa and 5.5%, improved by 20% and 44%, respectively, compared with the A356 alloy.

关键词： metal matrix composites SiC nanopaticles A356 aluminum alloy solid-liquid mixed casting ultrasonic vibration

low-Brightness Object Recognition Based on Deep learning

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Computers, Materials & Continua 2024年第5期79卷 1757-1773页

作者： shu-Yin Chiang Ting-Yu lin Department of Information and Telecommunications Engineering Ming Chuan UniversityTaoyuan City333Taiwan

This research focuses on addressing the challenges associated with image detection in low-light environments,particularly by applying artificial intelligence techniques to machine vision and object recognition systems.The primary goal is to tackle issues related to recognizing objects with low brightness levels.In this study,the Intel RealSense lidar Camera l515 is used to simultaneously capture color information and 16-bit depth information images.The detection scenarios are categorized into normal brightness and low brightness situations.When the system determines a normal brightness environment,normal brightness images are recognized using deep learning methods.In low-brightness situations,three methods are proposed for recognition.The first method is the SegmentationwithDepth image(SD)methodwhich involves segmenting the depth image,creating amask from the segmented depth image,mapping the obtained mask onto the true color(RGB)image to obtain a backgroundreduced RGB image,and recognizing the segmented image.The second method is theHDVmethod(hue,depth,value)which combines RGB images converted to HSV images(hue,saturation,value)with depth images D to form HDV images for recognition.The third method is the HSD(hue,saturation,depth)method which similarly combines RGB images converted to HSV images with depth images D to form HSD images for recognition.In experimental results,in normal brightness environments,the average recognition rate obtained using image recognition methods is 91%.For low-brightness environments,using the SD method with original images for training and segmented images for recognition achieves an average recognition rate of over 82%.TheHDVmethod achieves an average recognition rate of over 70%,while the HSD method achieves an average recognition rate of over 84%.The HSD method allows for a quick and convenient low-light object recognition system.This research outcome can be applied to nighttime surveillance systems or nighttime road safety systems.

关键词： low-brightness depth image image segmentation image recognition HDV HSD

Phase-dependent lithium-alloying reactions for lithium-metal batteries

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Chinese Chemical letters 2024年第4期35卷 1-2页

作者： shu lin Kezhen Qi College of Pharmacy Dali UniversityDali 671000China

With the increasing demand for higher energy lithium-ion batteries (lIBs), it is imperative to develop high-capacity electrode materials [1–4]. Due to the unique electrochemical li-alloying reactions, li-alloys offer high theoretical capacity, especially lithiumrich phase alloys, which exceeds the theoretical capacity of graphite anodes [5–7]. Phase-transition, which significantly influences lithium alloy reactions, determines high voltage hysteresis,low Coulombic efficiency (CE), and short cycling life [8,9].

关键词： alloying alloys cycling

Groundwater Quality and Vulnerability Assessment in a Semiarid Karst Region of Northern China

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Journal of Earth Science 2024年第1期35卷 313-316页

作者： Ran An shu Wang Zongjun Gao Zhenyan Wang Wei li Qijun Deng lü lin Yuanqing liu Key laboratory of Water Cycle and Related land Surface Processes Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China Shandong University of Science and Technology Qingdao 266510China Center for Hydrogeology and Environmental Geology Survey China Geological SurveyBaoding 071051China

Groundwater plays a critical role in maintaining ecological balance and ensuring social operations,especially in arid and semiarid regions(Hu et al.,2023;Han et al.,2022;Ma et al.,2014).The over-exploitation of groundwater,coupled with the influx of pollutants from human activities into the soil,significantly degrades the environment in certain regions(Jia et al.,2019;Famiglietti,2014;Giordano,2009;Konikow and Kendy,2005;Bohlke,2002;Shah et al.,2000).

关键词： groundwater Groundwater Vul