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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,Mechanical Properties and Die-Filling Behavior of High-Performance Die-Cast Al-Mg-Si-Mn Alloy

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Acta Metallurgica Sinica(English Letters) 2015年第11期28卷 1344-1353页

作者： Zu-Qi Hu Xin-Jian Zhang shu-sen wu Institute of Materials China Academy of Engineering Physics State Key Lab of Materials Processing and Die & Mould Technology Huazhong University of Science and Technology

This work aims to reveal the relationships between the microstructure, mechanical properties and flow behavior of die-casting AlMg5Si2Mn alloy. Results indicated that the microstructure of the die-cast AlMgsSi2Mn consists of α1-Al grains, fine-size α2-Al grains and （Al ＋ Mg2Si） eutectic. The surface layer observed has the thickness in a range of 120-135 μm, while an ellipse-like surface layer edge is observed in the corner of the plateqike sample. Tensile strength and elongation （3） of the specimens are slightly decreased along the die-filling direction due to the backflow of melt. Pure （Al ＋ Mg2Si） eutectic layer and ultra-fine-size α2-Al grains observed are around the overflow channels. Mass feeding is predominantly responsible for the superior mechanical properties of the round bars as compared to those of plate-like samples.

关键词： High-pressure die casting Aluminum alloy Microstructure segregations Mechanicalproperties Die-filling behavior Numerical simulation

Progress in preparation of AlN-reinforced magnesium matrix composites:A review

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China Foundry 2024年第1期21卷 1-10页

作者： Lu Chen shu-lin Lü Di-jia Zhao Wei Guo Jian-yu Li shu-sen wu State Key Lab of Materials Processing and Die&Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China

As a ceramic material,AlN has very good thermophysical and mechanical *** addition,AlN is an effective refining agent for Mg alloys because it has a lattice constant similar to that of ***,AlN is an ideal reinforcement for magnesium matrix composites(MMCs),and is attracting increasing *** review addresses the development of preparation technologies for AlN-reinforced Mg matrix *** mainstream preparation techniques include stir casting,melt infiltration,powder metallurgy,and in-situ *** addition,the advantages and disadvantages of these techniques are analyzed in depth,and it is pointed out that the next direction for the preparation of high-performance AlN-reinforced MMCs is less aluminization and multiple technologies integration.

关键词： AlN MMCs preparation thermophysical property mechanical property

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： magnesium alloy heat treatment microstructure mechanical properties

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-SiCp with an average diameter of 40 nm, and pre-oxidized at about 850 ℃ to form an oxide layer with a thickness of approximately 3 nm. The mm-sized composite granules containing nano-SiCp were firstly produced by milling the mixture of oxidized nano-SiCp 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 particles are distributed uniformly in the matrix and no serious agglomeration is observed. The tensile strength and elongation of the composite with 2wt.% nano-SiCp 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

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

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China Foundry 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 ***,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 *** 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 *** 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 *** the FSU is applied,the effective cavitation zone is obviously expanded in the *** increases at first and then decreases with increasing the vibration-source spacing(Lv)from 30 mm to 100 ***,when the Lv is 80 mm,the area of effective cavitation zone reaches the largest,indicating the best effect of ***,the acoustic streaming level and flow pattern in the melt also change with the increase of *** 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 *** 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

Semisolid slurry of 7A04 aluminum alloy prepared by electromagnetic stirring and Sc, Zr additions

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China Foundry 2017年第3期14卷 188-193页

作者： Jun-wen Zhao An Guo Hu Li Xu Zhang Jing Han shu-sen wu Key Lab of Advanced Technologies of Materials (Ministry of Education) School of Materials Science and Engineering Southwest Jiaotong University Chengdu 610031 China School of Mechanics and Engineering Southwest Jiaotong University Chengdu 610031 China State Key Lab of Materials Processing and Die & Mould Technology Huazhong University of Science and Technology Wuhan 430074 China

Slurry preparation is one of the most critical steps for semisolid casting, and its primary goal is to prepare slurry with uniformly distributed fine globules. In this work, electromagnetic stirring(EMS) and the addition of Sc and Zr elements were used to prepare semisolid slurry of 7A04 aluminum alloy in a large diameter slurry maker. The effects of different treatments on the microstructure, composition and their radial homogeneity were investigated. The results show that, compared to the slurry without any treatment, large volume slurry with finer and more uniform microstructure can be obtained when treated by EMS, Sc, or Zr additions individually. EMS is more competent in the microstructural and chemical homogenization of the slurry while Sc and Zr additions are more excellent in its microstructural refinement. The combined treatment of EMS, Sc and Zr produces premium 7A04 aluminum alloy slurry with uniformly distributed fine α-Al globules and composition. The interaction mechanism between EMS and Sc and Zr additions was also discussed.

关键词： aluminum alloy Zr and Sc additions semisolid slurry electromagnetic stirring(EMS) homogeneity

A new fast heat treatment process for cast A356 alloy motorcycle wheel hubs

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China Foundry 2018年第1期15卷 11-16页

作者： Shi-ping Lu Rui Du Jian-ping Liu Lin-can Chen shu-sen wu Zhejiang Wanfeng Motorcycle Wheel Co. Ltd. Xinchang 312500. Zhejiang. China State Key Lab of Materials Processing and Die &Mould Technology Huazhong University of Science and Technology Wuhan 430074 China

The normal T6 heat treatment process for cast A356 alloy generally requires about 15 h. This longperiod procedure increases greatly the manufacturing cost and decreases the productivity in practical production. In this study, a new short-time heat treatment process with only 30 min solution time at 540℃ was developed for the production of motorcycle wheel hubs in order to reduce heat treatment time. Comparisons on microstructure evaluation and mechanical properties, such as tensile strength and ductility, were made between this new fast process and the conventional T6 heat treatment. The results revealed that this new heat treatment process enabled the spheroidization of the eutectic silicon thoroughly, while minimizing the growth of eutectic silicon. The A356 alloy after this new short-time heat treatment shows nearly equal mechanical properties compared with the same alloy heat treated in a normal T6 heat treatment. This investigation makes it possible to significantly improve the efficiency of heat treatment on A356 alloy and, at the same time, improve the mechanical properties of the alloy.

关键词： A356 alloy short-time heat treatment microstructure evaluation mechanical properties

Microstructure evolution and mechanical properties of Mg-12Zn-2Y alloy containing quasicrystal phase fabricated by different casting processes

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China Foundry 2021年第2期18卷 147-154页

作者： Ji-guang Liu Bu-ke Dong Xiao-gang Fang Bin Li You-wen Yang Tian-yu wu Rui-dong Ren shu-sen wu School of Materials Science and Engineering Hefei University of TechnologyHefei 230009China State Key Lab of Materials Processing ami Die&Mould Technology Huazhong University of Science and TechnologyWuhan 430074China

Although icosahedral quasicrystal phase(denoted as I-phase)has been verified as an outstanding reinforcing phase,the mechanical properties of quasicrystal-reinforced Mg-Zn-Y alloys fabricated by traditional casting processes are still unsatisfactory due to the serious segregation of intermetallic *** this study,the microstructure and mechanical properties of Mg-12Zn-2Y alloy fabricated by different casting processes,including permanent mold casting,squeeze casting and rheo-squeeze casting with ultrasonic vibration,were systematically investigated and *** results show that massive,large-sized I-phase and Mg7Zn3 phase gather together in the permanent mold cast sample,while the squeeze casting process leads to the transformation of I-phase into fine lamellar morphology and the amount of Mg7Zn3 *** to the rheo-squeeze casting process,when the ultrasonic vibration is exerted with power from 800 W to 1,600 W,theα-Mg grains are refined and spheroidized to a large extent,and the lamellar spacing of the eutectic structure is significantly reduced,accompanied by some tiny granular I-phase scattering in theα-Mg ***,when the ultrasonic power continuously increases to 2,400 W,the eutectic structure becomes *** best mechanical properties of the rheo-squeeze cast alloy are obtained when the ultrasonic power is 1,600 *** microhardness,yield strength,ultimate tensile strength and elongation are 79.9 HV,140 MPa,236 MPa,and 3.25%,which are 44.1%,26.1%,25.5%,132.1%respectively higher than the corresponding values of the squeeze casting sample,and are 47.6%,44.3%,69.8%,and 253.3%respectively higher than the corresponding values of the permanent mold casting sample.

关键词： Mg-Zn-Y alloy quasicrystal rheo-squeeze casting ultrasonic vibration treatment

Effects of nano-SiC_p content on microstructure and mechanical properties of SiC_p/A356 composites assisted with ultrasonic treatment

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Transactions of Nonferrous Metals Society of China 2018年第11期28卷 2174-2181页

作者： Kun HU Du YUAN shu-lin Lü shu-sen wu State Key Laboratory of Materials Processing and Die ＆ Mould Technology Huazhong University of Science and TechnologyWuhan 430074China

nano-SiCp/A356 composites with different nano-SiCp contents were prepared by squeeze casting after ultrasonic treatment（UT）. The effects of SiCp content on the microstructure and mechanical properties of the nanocomposites were investigated. Theresults show that with the addition of nano-SiCp, the microstructure of nanocomposites is obviously refined, the morphology of theα（Al） grains transforms from coarse dendrites to rosette crystals, and long acicular eutectic Si phases are shortened and rounded. Themechanical properties of 0.5%, 1% and 2% （mass fraction） SiCp/A356 nanocomposites are improved continuously with the increaseof nano-SiCp content. Especially, when the SiCp content is 2%, the tensile strength, yield strength and elongation are 259 MPa,144 MPa and 5.3%, which are increased by 19%, 69% and 15%, respectively, compared with those of the matrix alloy. Theimprovement of strength is attributed to mechanisms of Hall？Petch strengthening and Orowan strengthening.

关键词： nano-SiCp aluminum matrix composites ultrasonic treatment microstructure mechanical properties