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Prediction of Damping Capacity Demand in Seismic Base Isolators via Machine Learning
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作者 Ayla Ocak Umit Isıkdag +3 位作者 Gebrail Bekdas Sinan Melih Nigdeli Sanghun Kim ZongWoo Geem 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第3期2899-2924,共26页
Base isolators used in buildings provide both a good acceleration reduction and structural vibration control structures.The base isolators may lose their damping capacity over time due to environmental or dynamic effe... Base isolators used in buildings provide both a good acceleration reduction and structural vibration control structures.The base isolators may lose their damping capacity over time due to environmental or dynamic effects.This deterioration of them requires the determination of the maintenance and repair needs and is important for the long-termisolator life.In this study,an artificial intelligence prediction model has been developed to determine the damage and maintenance-repair requirements of isolators as a result of environmental effects and dynamic factors over time.With the developed model,the required damping capacity of the isolator structure was estimated and compared with the previously placed isolator capacity,and the decrease in the damping property was tried to be determined.For this purpose,a data set was created by collecting the behavior of structures with single degrees of freedom(SDOF),different stiffness,damping ratio and natural period isolated from the foundation under far fault earthquakes.The data is divided into 5 different damping classes varying between 10%and 50%.Machine learning model was trained in damping classes with the data on the structure’s response to random seismic vibrations.As a result of the isolator behavior under randomly selected earthquakes,the recorded motion and structural acceleration of the structure against any seismic vibration were examined,and the decrease in the damping capacity was estimated on a class basis.The performance loss of the isolators,which are separated according to their damping properties,has been tried to be determined,and the reductions in the amounts to be taken into account have been determined by class.In the developed prediction model,using various supervised machine learning classification algorithms,the classification algorithm providing the highest precision for the model has been decided.When the results are examined,it has been determined that the damping of the isolator structure with the machine learning method is predicted successfully at a level exceeding 96%,and it is an effective method in deciding whether there is a decrease in the damping capacity. 展开更多
关键词 Vibration control base isolation machine learning damping capacity
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Damping capacity of high strength-damping aluminum alloys prepared by rapid solidification and powder metallurgy process 被引量:6
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作者 李国丛 马岳 +2 位作者 何晓磊 李伟 李沛勇 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第5期1112-1117,共6页
Two kinds of high strength-damping aluminum alloys (LZ7) were fabricated by rapid solidification and powder metallurgy (RS-PM) process. One material was extruded to profile aluminum directly and the other was extr... Two kinds of high strength-damping aluminum alloys (LZ7) were fabricated by rapid solidification and powder metallurgy (RS-PM) process. One material was extruded to profile aluminum directly and the other was extruded to bar and then rolled to sheet. The damping capacity over a temperature range of 25-300 ℃was studied with damping mechanical thermal analyzer (DMTA) and the microstructures were investigated by optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The experimental results show that the damping capacity increases with the test temperature elevating. Internal friction value of rolled sheet aluminum is up to 11.5×10^-2 and that of profile aluminum is as high as 6.0×10^-2 and 7.5×10^-2 at 300 ℃, respectively. Microstructure analysis shows the shape of precipitation phase of rolled alloy is more regular and the distribution is more homogeneous than that of profile alloy. Meanwhile, the interface between particulate and matrix of rolled sheet alloy is looser than that of profile alloy. Maybe the differences at interface can explain why damping capacity of rolled sheet alloy is higher than that of profile alloys at high temperature (above 120 ℃). 展开更多
关键词 damping capacity rapid solidification and powder metallurgy process composite materials damping mechanism
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Design optimization of cast Cu-Al-Be-B alloys for high damping capacity 被引量:8
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作者 S.Lu W.H.Miao +1 位作者 J.Chen P.H.Lin 《China Foundry》 SCIE CAS 2004年第S1期32-37,共6页
This paper investigated high-damping Cu-Al-Be-B cast alloys using metallographic analysis, X-ray diffraction (XRD) and electrical resistance measurements for transformation temperatures. The results showed that beryll... This paper investigated high-damping Cu-Al-Be-B cast alloys using metallographic analysis, X-ray diffraction (XRD) and electrical resistance measurements for transformation temperatures. The results showed that beryllium can stabilize β phase, resulting in a thermo-elastic martensite microstructure leading to high-damping capacity in cast Cu-Al-Be-B alloys. Trace additions of boron to Cu-Al-Be alloys can significantly refine the grains, providing high strength and ductility to the alloys. A factorial design of experiment method was used to optimize the composition and properties of cast Cu-Al-Be-B alloys. The optimal microstructure for thermo-elastic martensite can be obtained by adjusting the amounts of aluminum and beryllium to eutectoid or pseudo-eutectoid compositions. An optimized cast Cu-Al-Be-B alloy was developed to provide excellent mechanical properties, tensile strength σ_b=767MPa, elongation δ=7.62%, and damping capacity S. D. C=18.70%. 展开更多
关键词 Cu-Al-Be-B alloys damping capacity mechanical property thermo-elastic martensite grain refining shape memory alloys(SMA)
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Effects of Y and Zn on mechanical properties and damping capacity of Mg-Cu-Mn alloy 被引量:6
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作者 王敬丰 魏文文 +2 位作者 李龙 梁浩 潘复生 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第10期1846-1850,共5页
Optical microscope,X-ray diffractometer,scanning electron microscope,tensile tester and dynamic mechanical analyzer(DMA) were applied to investigate the effects of Y and Zn additions on microstructure,mechanical prope... Optical microscope,X-ray diffractometer,scanning electron microscope,tensile tester and dynamic mechanical analyzer(DMA) were applied to investigate the effects of Y and Zn additions on microstructure,mechanical properties and damping capacity of Mg-3Cu-1Mn(CM31) alloy.The results show that with the increase of Y and Zn contents,the secondary dendrite arm spacing of alloys is reduced;meanwhile,the yield strength is increased.In low strain amplitude,the damping capacity of alloys with Y and Zn addition is lower than that of CM31 alloy.However,in strain amplitude over 5×10-3,the damping capacity of alloy with a trace of Y and Zn addition(1%Y and 2%Zn,mass fraction) increases abnormally with the increase of strain amplitude and is near to that of pure Mg,probably due to the increase of dislocation density caused by the precipitation of secondary phase.The temperature dependence of damping capacity of above alloy was also tested and discussed. 展开更多
关键词 Mg-Cu-Mn alloy Y ZN magnesium alloys damping capacity Granato-Lucke theory
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Effects of Y content and temperature on the damping capacity of extruded Mg-Y sheets 被引量:9
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作者 Y.T.Tang C.Zhang +5 位作者 L.B.Ren W.Yang D.D.Yin G.H.Huang H.Zhou Y.B.Zhang 《Journal of Magnesium and Alloys》 SCIE 2019年第3期522-528,共7页
The damping behavior of extruded Mg-xY(x=0.5,1.0,3.0 wt.%)sheets were investigated in detail concerning the effects of Y addition and temperature,and the relationship between damping capacity and yield strength was di... The damping behavior of extruded Mg-xY(x=0.5,1.0,3.0 wt.%)sheets were investigated in detail concerning the effects of Y addition and temperature,and the relationship between damping capacity and yield strength was discussed.At room temperature(RT),with Y content increasing from 0.5%to 3.0%,the damping capacity(Q-1)significantly decreased from 0.037 to 0.015.For all the studied sheets,the relationship between strain amplitude and Q-1 fitted well with the Granato and Liicke(G-L)dislocation damping model.With temperature increased,the G-L plots deviated from linearity indicating that the dislocation damping was not the only dominate mechanism,and the grain boundary sliding(GBS)could contribute to damping capacity.Consequently,the Q-1 increased remarkably above the critical temperature,and the critical temperature increased significantly from 50℃ to 290℃ with increasing Y contents from 0 to 3.0wt.%.This result implied that the segregation of Y solutes at grain boundary could depress the GBS,which was consistent with the recent finding of segregation tendency for rare-earth solutes.The extruded Mg-IY sheet exhibited slightly higher yield strength(Rp0.2)and Q-1 comparing with high-damping Mg-0.6Zr at RT.At an elevated temperature of 325℃,the Mg-IY sheet had similar Q-1 but over 3 times larger Rp0.2 than that of the pure Mg.The present study indicated that the extruded Mg-Y based alloys exhibited promising potential for developing high-performance damping alloys,especially for the elevated-temperature application. 展开更多
关键词 Extruded sheets Mg-Y alloys damping capacity Granato and Lücke model Elevated temperature
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Solid solution strengthening and damping capacity of Mg-Ga binary alloys 被引量:4
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作者 Wen-sen HUANG Ji-hua CHEN +4 位作者 Hong-ge YAN Qiang LI Wei-jun XIA Bin SU Wei-jun ZHU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2022年第9期2852-2865,共14页
The mechanical behaviors and damping capacities of the binary Mg−Ga alloys with the Ga content ranging from 1 to 5 wt.%were investigated by means of optical microscope(OM),scanning electron microscope(SEM),X-ray diffr... The mechanical behaviors and damping capacities of the binary Mg−Ga alloys with the Ga content ranging from 1 to 5 wt.%were investigated by means of optical microscope(OM),scanning electron microscope(SEM),X-ray diffraction(XRD),hardness test,tensile test and dynamic mechanical analyzer(DMA).The hardness(HV_(0.5))increases with the increase of Ga content,which can be described as HV_(0.5)=41.61+10.35c,and the solid solution strengthening effect∆σ_(s)of the alloy has a linear relationship with c^(n),where c is the molar fraction of solute atoms and n=1/2 or 2/3.Ga exhibits a stronger solid solution strengthening effect than Al,Zn or Sn due to the large atomic radius difference and the modulus mismatch between Ga and Mg atoms.The addition of Ga makes the Mg−Ga alloys have better damping capacity,and this phenomenon can be explained by the Granato−Lücke dislocation model.The lattice distortion and the modulus mismatch generated because of the addition of Ga increase the resistance to motion of the dislocation in the process of swinging or moving,and thus the better damping capacity is acquired. 展开更多
关键词 Mg-Ga alloys solid solution strengthening damping capacity Granato-Lücke model
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Influence of RE Content on Damping Capacity of Alloy ZA27 被引量:3
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作者 Zhang, Zhongming Wang, Jincheng +3 位作者 Xu, Donghui Lu, Yili Yang, Gencang Zhou, Yaohe 《Journal of Rare Earths》 SCIE EI CAS CSCD 1999年第2期43-46,共4页
The modification mechanism and damping capacity(Q-1) of conventional ascast ZA27 alloy modified by Al10%RE were investigated. Cantilever beam technique was used to measure the damping capacity. The experimental result... The modification mechanism and damping capacity(Q-1) of conventional ascast ZA27 alloy modified by Al10%RE were investigated. Cantilever beam technique was used to measure the damping capacity. The experimental results show that the addition of RE to the ZA27 alloy can refine microstructure and improve the damping capacity, the best modification effect and the highest damping capacity can be obtained at 03%RE content. It is believed that the damping mechanism of ZA27 alloy is associated with the viscous sliding or slipping of grain boundaries and interfaces, and the more the grain boundaries and interfaces, the higher the damping capacity of ZA27 alloy can be obtained. 展开更多
关键词 Rare Earths ZnAl alloy MODIFICATION damping capacity damping mechanism
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A Novel TiNi/AlSi Composite with High Strength and High Damping Capacity 被引量:3
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作者 Shuwei LIU Xiuyan LI Desheng YAN Haichang JIANG Lijian RONG 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2008年第6期903-906,共4页
A novel TiNi/AlSi composite with high compressive strength and high damping capacity was obtained by infiltrating Al-12%Si alloy into porous TiNi alloy.It had been found that the high compressive strength (440 MPa) of... A novel TiNi/AlSi composite with high compressive strength and high damping capacity was obtained by infiltrating Al-12%Si alloy into porous TiNi alloy.It had been found that the high compressive strength (440 MPa) of TiNi/AlSi composite is due to the increase of effective carrying area after infiltrating Al-12%Si alloy,while the high damping capacity is contributed to TiNi carcass,Al-12%Si filling material and micro- slipping at the interface. 展开更多
关键词 damping capacity Internal friction TiNi/AlSi composite Compressive strength
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Effects of Y on mechanical properties and damping capacity of ZK60 magnesium alloys 被引量:2
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作者 王敬丰 高珊 +3 位作者 赵亮 梁浩 胡耀波 潘复生 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第B07期366-370,共5页
The microstructure,mechanical properties and damping capacity of ZK60-xY(x=0,1.5%,2.5%,4.0%,mass fraction) magnesium alloys were investigated by using the optical microscope(OM),X-ray diffractometer(XRD),universal ten... The microstructure,mechanical properties and damping capacity of ZK60-xY(x=0,1.5%,2.5%,4.0%,mass fraction) magnesium alloys were investigated by using the optical microscope(OM),X-ray diffractometer(XRD),universal tensile testing machine and dynamic mechanical analyzer(DMA).The mechanisms for damping capacity of referred alloys were discussed by Granato-Lücke theory.The results show that Y additions remarkably reduce grain size(the average grain size is 21.6,13.0,8.6 and 4.0μm,respectively),and the tensile properties are enhanced with grain refining(the yield tensile strength increases to 292 MPa from 210 MPa and ultimate tensile strength increases to 330 MPa from 315 MPa).For the ZK60-xY(x=0,1.5%,4.0%)alloys,the damping capacity decreases with the increase of Y content.However,for the ZK60-xY(x=2.5%)alloy,the damping capacity improves abnormally,which is possibly related to the formation of Mg3Y2Zn3(W)FCC phase in this alloy. 展开更多
关键词 magnesium alloys MICROSTRUCTURE mechanical property damping capacity Granato-Lücke Theory
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Optimization on microstructure,mechanical properties and damping capacities of duplex structured Mg–8Li–4Zn–1Mn alloys 被引量:2
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作者 Tongtong Cao Yong Zhu +7 位作者 Yuyang Gao Yan Yang Gang Zhou Xiaofei Cui Chen Wen Bin Jiang Xiaodong Peng Fusheng Pan 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2023年第5期949-958,共10页
Optimizing the mechanical properties and damping capacity of the duplex-structured Mg–Li–Zn–Mn alloy by tailoring the microstructure via hot extrusion was investigated.The results show that the Mg–8Li–4Zn–1Mn al... Optimizing the mechanical properties and damping capacity of the duplex-structured Mg–Li–Zn–Mn alloy by tailoring the microstructure via hot extrusion was investigated.The results show that the Mg–8Li–4Zn–1Mn alloy is mainly composed ofα-Mg,β-Li,Mg–Li–Zn and Mn phases.The microstructure of the test alloy is refined owing to dynamic recrystallization(DRX)during hot extrusion.After hot extrusion,the crushed precipitates are uniformly distributed in the test alloy.The yield strength(YS),ultimate tensile strength(UTS),and elongation(EL)of as-extruded alloy reach 156 MPa,208 MPa,and 32.3%,respectively,which are much better than that of as-cast alloy.Furthermore,the as-extruded and as-cast alloys both exhibit superior damping capacities,with the damping capacity(Q^(-1))of 0.030 and 0.033 at the strain amplitude of 2×10^(-3),respectively.The mechanical properties of the test alloy can be significantly improved by hot extrusion,whereas the damping capacities have no noticeable change,which indicates that the duplex-structured Mg–Li alloys with appropriate mechanical properties and damping properties can be obtained by alloying and hot extrusion. 展开更多
关键词 magnesium–lithium alloys hot extrusion MICROSTRUCTURE mechanical properties damping capacity
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INFLUENCE OF ZIRCONIUM ON MICROSTRUCTURE AND DAMPING CAPACITY OF ZA27 ALLOY
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作者 J.C.Wang Z.M.Zhang +2 位作者 Y.L.Lu G.S.Song G.C.Yang 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1998年第3期230-234,共5页
To improve the damping capacities of metals and alloys, the microstructures and damping capacities of ZA27 alloy modified by Zr were studied, and the damping capacities at room tempemture were measured by using cantil... To improve the damping capacities of metals and alloys, the microstructures and damping capacities of ZA27 alloy modified by Zr were studied, and the damping capacities at room tempemture were measured by using cantilever beam techniques. The experiment results show that Zr can refine the Al-rich primary phase and improve the damping Capacities saliently. Compared with the un-modified one, the damping capacity of ZA27 alloy modified by 0.3wt%Zr received 90 percent increment. The high damping capacities are attributed primarily to grain ablement and the increasing of phase interfaces. 展开更多
关键词 ZA27 alloy damping capacity MODIFICATION MICROSTRUCTURE
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DAMPING CAPACITY OF HIGH SILICON ALLOY ZA27 PREPAREDBY SPRM DEPOSITION
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作者 L.S. Yang Y.C Liu G.C Yang and Y.H Zhou(State Key Lab. of Solidification Processing, Northwestern Polytechnical University Xi’an 710072, China) 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1997年第1期46-50,共5页
The damping capacities (Q-1) of high silicon (6wt%) Zinc-27wt% Aluminia alloy prepared by spray deposition and conventional casting process were investigated. Three methods, free-decay, half-power band width and phase... The damping capacities (Q-1) of high silicon (6wt%) Zinc-27wt% Aluminia alloy prepared by spray deposition and conventional casting process were investigated. Three methods, free-decay, half-power band width and phase angles difference, have been ased to measure the damping capacities of the experimental materiale. The experimental results indicate that the damping capacity of spray deposited material is 3.7times larger than that of the conventional casting alloy ZA27 The machanism for its improvement was aiso investigated from a microstructvre viempoint. 展开更多
关键词 high damping alloy damping capacity spray deposition MICROSTRUCTURE
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Damping capacity of amorphous carbon fiber/aluminum matrix composites at room temperature
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作者 LI Aibin,WANG Hongmei,LI Shasha,and ZHENG Peiqi School of Materials Science and Engineering,Harbin Institute of Technology,Harbin 150001,China 《Rare Metals》 SCIE EI CAS CSCD 2007年第S1期115-119,共5页
The influence of volume fraction on damping capacities at room temperature for amorphous carbon fiber reinforced aluminum matrix composites was investigated.At room temperature,the dislocation damping is the primary d... The influence of volume fraction on damping capacities at room temperature for amorphous carbon fiber reinforced aluminum matrix composites was investigated.At room temperature,the dislocation damping is the primary damping mechanism.Meanwhile,the dislocation damping exhibits dynamic hysteresis at low strain amplitudes and static hysteresis at high strain amplitudes.Moreover,the damping capacity is rather sensitive to the volume fraction.Compared to unreinforced aluminum alloy,the additions of amorphous carbon fibers into the aluminum matrix can improve damping capacity below the volume fraction of 30%,whereas worsen above the volume fraction of 40%. 展开更多
关键词 carbon fiber aluminum matrix composite damping capacity volume fraction
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Low frequency damping capacities of commercial pure magnesium
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作者 胡小石 王晓军 +2 位作者 赫晓东 吴昆 郑明毅 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第8期1907-1911,共5页
The amplitude-dependent and temperature-dependent low frequency damping capacities of magnesium with 99.96% purity were studied by a dynamic mechanical analyzer. The pure magnesium alloys include CPM1 and CPM2 casting... The amplitude-dependent and temperature-dependent low frequency damping capacities of magnesium with 99.96% purity were studied by a dynamic mechanical analyzer. The pure magnesium alloys include CPM1 and CPM2 castings having textures of columnar grains which extraordinarily influence the damping behaviours. The commercial pure magnesium alloy CPM was re-melted to obtain equiaxed grains, which could remove the effect of texture orientation on the damping behaviours of these pure magnesium alloys. The results of strain amplitude-dependent damping spectrums of these pure magnesium alloys show that the pure magnesium with equiaxed grains possesses the highest damping capacity. In temperature-dependent damping plot for all these three pure magnesium alloys, there are two damping peaks P1 and P2 located at 80 and 230 °C, respectively. These two damping peaks are considered to be caused by the interaction between dislocation and point defects, and the movement of grain boundaries, respectively. 展开更多
关键词 commercial pure magnesium crystal orientation damping capacity casting texture AGING crystal defects
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The transformation of LPSO type in Mg-4Y-2Er-2Zn-0.6Zr and its response to the mechanical properties and damping capacities 被引量:18
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作者 Dan Wang Huajie Wu +6 位作者 Ruizhi Wu Yang Wang Jinghuai Zhang Sergey Betsofen Boris Krit Legan Hou Turahodjayev Nodir 《Journal of Magnesium and Alloys》 SCIE EI CAS 2020年第3期793-798,共6页
The transformation of LPSO type in Mg-4Y-2Er-2Zn-0.6Zr during heat treatment and its influence on damping and mechanical properties are reported in this work.Prior to heat treatment,the alloy consisted of a-Mg matrix ... The transformation of LPSO type in Mg-4Y-2Er-2Zn-0.6Zr during heat treatment and its influence on damping and mechanical properties are reported in this work.Prior to heat treatment,the alloy consisted of a-Mg matrix and lamellar 14H LPSO phases.After 510℃heat treatment,lamellae shortened,and their content decreased.Upon 8h heat treatment,block 18R LPSO phases formed at the grain boundaries while 14H LPSO lamellae disappeared.Presence of block 18R LPSO phases improved mechanical and damping properties of the alloy.The corresponding mechanisms of the influence of LPSO type and morphology on mechanical and damping capacities are discussed. 展开更多
关键词 Heat treatment LPSO phases Mechanical properties damping capacities
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Optimization of mechanical and damping properties of Mg-0.6Zr alloy by different extrusion processing 被引量:6
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作者 Jingfeng Wang Zhongshan Wu +4 位作者 Shan Gao Ruopeng Lu Dezhao Qin Wenxiang Yang Fusheng Pan 《Journal of Magnesium and Alloys》 SCIE EI CAS 2015年第1期79-85,共7页
In this study,the optimization of mechanical and damping capacities of Mg-0.6 wt.%Zr alloys by controlling the recrystallized(DRXed)grain size under varying extrusion processing parameters including extrusion temperat... In this study,the optimization of mechanical and damping capacities of Mg-0.6 wt.%Zr alloys by controlling the recrystallized(DRXed)grain size under varying extrusion processing parameters including extrusion temperature T and strain rate was investigated.The relationship between the DRXed grain size and damping properties of the studied alloy was also discussed.The DRXed grain size of the as-extruded Mg-Zr alloys decreased as the extrusion temperature T decreased and the strain rateεincreased.As the DRXed grain size decreased,the strength and elongation of the as-extruded alloys exhibited improved performance through the grain refinement mechanism,while the damping properties deteriorated.The extrusion temperature of the Mg-Zr alloy had relatively greater effects on the mechanical and damping properties than the strain rate.The results of the present work indicate that alloys with appropriate mechanical and damping properties may be obtained from controlling the DRXed grain size by careful tailoring of the extrusion process parameters. 展开更多
关键词 Mg-Zr alloy Mechanical properties damping capacities EXTRUSION OPTIMIZATION
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Influence of B4C particle size on microstructure and damping capacities of(B_(4)C+Ti)/Mg composites 被引量:5
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作者 YAO Yan-tao CHEN Li-qing WANG Wen-guang 《Journal of Central South University》 SCIE EI CAS CSCD 2021年第3期648-656,共9页
To study the influence of B4C particle size on the microstructure and damping capacities of(B_(4)C+Ti)/Mg composites,in situ reactive infiltration technique was utilized to prepare Mg-matrix composites.The microstruct... To study the influence of B4C particle size on the microstructure and damping capacities of(B_(4)C+Ti)/Mg composites,in situ reactive infiltration technique was utilized to prepare Mg-matrix composites.The microstructure,produced phases and damping capacities of the composites prepared with different particle size of B4C were characterized and analyzed.The results show that the reaction between B4C and Ti tends to be more complete when finer B_(4)C particle was used to prepare the composites.But the microstructure of the as-prepared composites is more homogenous when B4C and Ti have similar particle size.The strain-dependent damping capacities of(B_(4)C+Ti)/Mg composites improve gradually with the increase of strain amplitude,and composites prepared with coarser B4C particles tend to have higher damping capacities.The temperature-dependent damping capacities improve with increasing the measuring temperatures,and the kind of damping capacities of the composites prepared with 5mm B4C are inferior to those of coarser particles.The dominant damping mechanism for the strain-damping capacity is dislocation damping and plastic zone damping,while that for the temperature-damping capacity is interface damping or grain boundary damping. 展开更多
关键词 Mg-matrix composites in situ reactive infiltration particle size MICROSTRUCTURE damping capacity mechanism
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EFFECT OF ANNEALING ON DAMPING CAPACITIES OF AS-CAST ZA27 ALLOY 被引量:3
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作者 Z.M. Zhang J. C. Wang +1 位作者 H.Z. Liu X.F. Guo 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2006年第5期379-384,共6页
ZA27 alloy was prepared by casting with permanent mold and then annealed at 250℃ for 1-4h. The damping capaciG of the alloy was measured using a testing apparatus based on the cantilever beam technique. It was found ... ZA27 alloy was prepared by casting with permanent mold and then annealed at 250℃ for 1-4h. The damping capaciG of the alloy was measured using a testing apparatus based on the cantilever beam technique. It was found that the as-cast ZA27 alloy possesses high damping capacity with the value of 1.3 × 10^4 at 320Hz. After annealed at 250℃ for lh, the damping capacity decreases to 1.1 × 10^-3 and then remains constant even when the annealing time is increased to 4h. The microstructure of the as-cast ZA27 alloy consists of large dendrites of Al-rich PrimaG (x-phases, eutectoid (α + η) and nonequilibrium eutectic phases (α + η + ε). After annealing at 250℃ for lh, the e phase disappears due to dissolution into the matrix, and the spacing between the flakes of eutectoid increases. The further increase in the annealing time has little effect on the spacing. The damping mechanism of the alloy was discussed considering the thermoelastic damping and defect damping. The value of thermoelastic damping accounts only for 7%-8% in the overall damping in cantilever beam damping measurements and the damping capacity of the ZA27 alloy came mainly from defect damping. 展开更多
关键词 damping capacity ZA27 alloy ANNEALING
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Effect of small tensile deformation on damping capacities of Mg-1%Al alloy 被引量:2
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作者 胡小石 赫晓东 +1 位作者 郑明毅 吴昆 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第B07期444-447,共4页
Tensile tests with small deformation amounts of 0.5%,1%,3%and 5%were performed at room temperature on as cast Mg-1%Al alloy.Microstructures of the Mg-1%Al alloys before and after deformation were observed by optical m... Tensile tests with small deformation amounts of 0.5%,1%,3%and 5%were performed at room temperature on as cast Mg-1%Al alloy.Microstructures of the Mg-1%Al alloys before and after deformation were observed by optical microscopy(OM) and transmission electron microscopy(TEM).The strain amplitude dependent and temperature dependent damping capacities of the as-cast and deformed Mg-1%Al alloys were investigated by dynamic mechanical analysis(DMA).The mechanism of deformation on damping capacity of Mg-1%Al alloy was discussed.The results show that the as-cast Mg-1%Al alloy has high damping value at high strain.When the tensile elongation is higher than 3%,the damping values of this alloy in high strain region are significantly decreased at room temperature.But the large amount of dislocations produced by tensile deformation are activated by heat,and then increase the damping value at high temperature. 展开更多
关键词 Mg-1%Al alloy tensile deformation damping capacity dislocations TEMPERATURE
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DAMPING BEHAVIOR OF ULTRAFINE-GRAINED PURE ALUMINUM L2 AND THE DAMPING MECHANISM 被引量:1
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作者 Z.M. Zhang C.J. Xu +1 位作者 J.C. Wang H.Z. Liu 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2006年第3期223-227,共5页
Ultrafine-grained pure aluminum L2 with a mean grain size of 1.01μm was produced by equal channel angular pressing (ECAP) and annealing at 150℃ for 2h. Damping behavior of the alloy was measured using a dynamic me... Ultrafine-grained pure aluminum L2 with a mean grain size of 1.01μm was produced by equal channel angular pressing (ECAP) and annealing at 150℃ for 2h. Damping behavior of the alloy was measured using a dynamic mechanical thermal analyzer. The alloy had an excellent damping capacity Q^-1 with the ambient value being 9.8×10^-3 at 1.0Hz when the strain amplitude was 2.0×10^-5. The damping behavior of the alloy showed a non-linear damping variation tendency, that is, with an increase in temperature and a decrease of frequency, the damping capacity of the alloy increased. The damping capacity increased with the strain amplitude when the strain amplitude was less than 4.6×10^-5. When the strain amplitude was higher than 4.6×10^-5, the damping capacity became a constant and independent of strain amplitude. The high damping capacity was attributed to dislocation unpinning and a drag of dislocation on pinning points. 展开更多
关键词 ECAP ultrafine grain damping capacity aluminum alloy
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