可调阻尼减振器ADS阀阻尼特性测试平台设计与试验研究

可调阻尼减振器依靠旁置的阻尼控制阀(以下简称ADS阀)来实现阻尼力的变化。ADS阀性能优劣的评判标准是阻尼特性,而该标准的测试需要将ADS阀与减振器主筒连接在一起进行试验分析,为此设计了专用的可调阻尼减振器ADS阀阻尼特性测试平台。借助此测试平台可以分别对可调阻尼减振器整机和ADS阀的阻尼特性进行试验研究。试验表明:该测试平台能够获得ADS阀各个挡位下的阻尼特性图和可调阻尼减振器在各种工况下的示功图,为可调阻尼汽车减振器的性能分析提供了有效手段。     

蠕变时效后Al-Mg-Si-Cu合金的阻尼性能

采用RDL50电子蠕变试验机和MFP-1000阻尼测试机,对蠕变时效后Al-Mg-Si-Cu合金进行阻尼测试,研究了不同工艺参数对蠕变时效后Al-Mg-Si-Cu合金阻尼性能的影响;同时也研究了人工时效后Al-Mg-Si-Cu合金的阻尼性能。研究结果表明:人工时效改善了Al-Mg-Si-Cu合金的阻尼性能;时效温度对Al-Mg-Si-Cu合金蠕变时效后的阻尼性能的影响最大; Al-Mg-Si-Cu合金的阻尼值在时效温度170℃,时效时间3 h,应力200 MPa下达到最大,为0. 181。     

水平连铸灰铁HT250型材的阻尼行为

选用直径为55mm的水平连铸灰铁HT250棒材,利用动态热机械分析仪测试型材的阻尼性能随振幅、频率和温度的变化关系,探讨灰铸铁型材的阻尼机制。研究表明,灰铸铁型材的阻尼性能随振幅和频率的提高而增加。在40℃附近出现斯诺克温度内耗峰。斯诺克峰的出现,使型材的阻尼性能随温度的变化在高低温时表现出完全不同的趋势。存在一临界应变振幅范围,大应变振幅下的阻尼性能远高于小应变振幅下的阻尼性能。灰铸铁型材的阻尼温度效应主要来源于点缺陷阻尼。位错阻尼在阻尼频率效应和阻尼振幅效应中起了主导作用,决定了型材的阻尼-频率行为和阻尼振幅行为。     

Mn-Cu阻尼合金减振性能的研究

利用倒扭摆和振动测试装置,研究了Mn-Cu阻尼合金的阻尼性能与其构件的减振性能.结果表明:Mn-Cu阻尼合金具有良好的力学性能,同18-8不锈钢相比,该合金具有显著的高阻尼性能；Mn-Cu合金的阻尼效果随应变振幅的增加而迅速增加,在应变振幅2×10-4左右出现平台；在自由振动条件下和受迫振动条件下,与18-8不锈圆桶相比,Mn-Cu合金圆桶构件表现出优良的减振性能.     

振动环境中镁/珍珠岩复合材料的阻尼性能研究

利用真空浸渗法制备了镁合金/珍珠岩复合材料,并利用DTM-Ⅱ-X型动态弹性模量阻尼内耗分析仪在共振条件下测试了其杨氏模量及阻尼内耗值,分析了其阻尼机理。试验结果表明,镁合金/珍珠岩金属基复合材料的阻尼性能要大大优于基体金属的。     

电弧离子镀沉积NiCrAlY涂层的阻尼性能

本文采用电弧离子镀沉积NiCrAlY涂层,探讨NiCrAlY涂层作为阻尼涂层的可行性并研究涂层的阻尼测试方法和阻尼特性。本文采用X射线衍射和扫描电镜等手段分别对涂层的物相结构、表面形貌以及化学成分进行了测试表征。而涂层阻尼的测试则采用动态机械分析仪和正弦扫频的方法进行,实验结果表明NiCrAlY涂层能明显提高样品的阻尼性能。     

时效温度对Fe-19Mn合金阻尼性能的影响

从Fe-Mn合金的阻尼机制出发,研究了不同时效温度对Fe-19Mn合金阻尼性能的影响.采用倒扭摆测试合金的阻尼性能,光学显微镜观察合金的微观组织,XRD分析合金的相组成,DSC测试相变点.结果表明,当时效温度在奥氏体开始转变温度As以下时,ε马氏体形态保持不变,由于淬火空位的浓度降低,阻尼性能提高;当时效温度高于As,ε马氏体先变粗,减少了阻尼源的数量,后随时效温度的增加而明显细化,使得阻尼源长度变短并阻碍了阻尼源的运动,阻尼性能降低.     

电弧离子镀沉积NiCrAlY涂层的阻尼性能（英文）

采用电弧离子镀沉积NiCrAlY涂层,探讨NiCrAlY涂层作为阻尼涂层的可行性并研究涂层的阻尼测试方法和阻尼特性。采用X射线衍射和扫描电镜等手段分别对涂层的物相结构、表面形貌以及化学成分进行了测试表征。而涂层阻尼的测试则采用动态机械分析仪和正弦扫频的方法进行,实验结果表明NiCrAlY涂层能明显提高样品的阻尼性能。     

振动环境中锌铝/珍珠岩多孔复合材料的阻尼性能研究

讨论了振动环境中锌铝/珍珠岩多孔复合材料的阻尼性能.实验利用真空浸渗法制备了锌铝合金/珍珠岩复合材料,并利用DTM-Ⅱ-X型动态弹性模量阻尼内耗分析仪在共振条件下测试其杨氏模量及材料阻尼内耗值,分析了其阻尼机理.试验结果表明锌铝合金/珍珠岩金属基复合材料的阻尼性能要大大优于基体金属.     

微合金化对镁合金阻尼性能的影响分析

在镁合金中复合添加了合金元素V和Sc,并进行了显微组织、物相组成和阻尼性能的测试与分析。结果表明:与未添加合金元素V和Sc的镁合金相比,合金元素V和Sc的添加可提高合金的阻尼性能;在0.6Hz相同频率下,20℃时阻尼性能增加149.52%,在20℃的相同温度下,0.2 Hz时的阻尼性能增加66.27%,1Hz时的阻尼性能增加了673.53%。     

Dehydrogenation of Hydrogenated Ti-6Al-4V Alloy

对未置氢及置氢Ti-6Al-4V合金进行了TG/DSC试验,研究了置氢钛合金的除氢行为。结果表明,当温度超过600℃时,置氢钛合金的失重规律与未置氢钛合金具有较大的差别。当加热温度在600~900℃之间时,置氢钛合金的失重随着氢含量的增加而增加。这是由于置氢合金中的亚稳相发生了分解。不考虑合金氧化的影响,置氢钛合金的最大失重与合金中的氢含量一致。置氢钛合金的最佳除氢温度为750℃。对于不同氢含量的置氢钛合金,其除氢工艺是相同的。     

Superelastic damping of TiNi alloy wire under heavy mechanical shock in structural engineering

Based on superelastic damping application in structural engineering, the damping characteristics of commercial Ti-50.8Ni(mole fraction, %) alloy have been systematically studied by adjusting frequency of mechanical shock, temperature, stress, strain and number of cycling. The results show that at extremely low frequency mechanical shock at room temperature, the superelastic damping capacity increases with controlled strain, and such capacity of each cycle is greater than 50%. When the frequency of mechanical shock is 0.1 -0.3 Hz, the superelastic damping capacity above room temperature is relatively large at high strain; when the temperature approaches to Md,the damping begins at low stress. For specimen cycled under 0.5 Hz, above 6 % strain mechanical shock at relatively high temperature, further large-strain cycling exhibits more than 35 % damping capacity. The superelastic damping of trained specimen is relatively stable at 20 - 50℃ and 0.1 - 0.5 Hz frequency mechanical shock.     

High-Temperature Oxidation Behavior of Ti-22Al-27(Nb, Zr) Alloys

研究了Ti2Al Nb基合金Ti-22Al-(27-x)Nb-x Zr(x=0,1,6,at%)在650~800℃的氧化行为。采用XRD和SEM等测试技术对此温度区间形成的氧化层特征进行了分析。结果表明,相比Ti-22Al-27Nb,含锆合金具有较好的抗氧化性能。Ti-22Al-(27-x)Nb-x Zr合金在650℃氧化100 h,主要氧化产物为Ti O2,而在800℃氧化100 h,Ti O2,Al2O3和Al Nb O4为主要产物,但是在Ti-22Al-21Nb-6Zr合金中还有Zr O2生成。Ti-22Al-26Nb-1Zr合金具有优异抗氧化性能,归因于氧化产物细化形成了致密的氧化层,而Ti-22Al-21Nb-6Zr合金,虽然在800℃也形成了较多Al2O3,但是氧化层中的Zr O2为氧的快速扩散提供通道,进而导致该合金氧化增重明显。     

Ti-6Al-4V合金的温轧织构演变

本研究采用取向分布函数(ODF)详细分析了具有等轴组织的Ti-6Al-4V热轧退火板在450、600和750℃下经过约45%的温轧压下量后沿层厚的宏观织构演变。结果表明采用多道次温轧的方法成功获得可改善Ti-6Al-4V合金力学性能各向异性的纤维织构ND//hkil和基面织构(0001)[2110]或(0001)[1210]。而且,轧板通体上均形成了ND//hkil纤维织构,中心层的横向织构(1210)[1010]随轧制温度而变化,表层的基面织构通过位错滑移累积剪切应变而产生,且基面织构的形成路径依赖于初始取向。     

铸态Ti-46Al-6(Cr, Nb, Si, B)合金的高温流变行为及其组织演变

以3次真空自耗熔炼的Ti-46Al-6(Cr,Nb,Si,B)(at%)(以下简称G4合金)合金为对象,采用恒温等应变速率热模拟压缩试验研究G4合金在1050～1250℃及0.001～1s-1应变速率下的高温流变行为和组织演变。结果表明,在高温变形过程中,G4合金呈现先硬化后软化的流变行为特征,组织由粗大的铸态γ+γ/α2近片层组织演变为细小的近等轴γ+α2组织;造成G4合金流变软化和组织演变的主要原因是动态再结晶(DRX)。变形温度和应变速率是影响G4合金高温流变和组织演变的2个主要因素。铸态G4合金在高温下的变形机制以γ/α2层片晶团的扭折、弯曲、球化和DRX以及γ晶粒的拉长、破碎和DRX为主,孪生变形也起到了一定的辅助作用。其最佳高温塑性变形温度为1150℃,应变速率应不大于0.1s-1。     

DAMPING BEHAVIOR OF ULTRAFINE-GRAINED PURE ALUMINUM L2 AND THE DAMPING MECHANISM

Ultrafine-grained pure aluminum L2 with a mean grain size of 1.0μm 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 2.0×10-3. 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.     

基于有限元理论分析切削振动对CBN刀具磨损的影响

研究用CBN刀具切削钛合金Ti-6Al-4V材料时，切削振动对刀具磨损的影响情况。用有限元分析技术，设计正交试验，分析不同方向切削振动幅度和振动频率对刀具表面应力、刀具温度的影响，研究切削振动条件下的刀具磨损情况。有限元仿真结果表明:X方向振动对刀具表面应力和温度影响较小，且规律性影响不明显，因此X方向振动并未加重刀具磨损；Y方向振动对刀具表面应力和温度影响较大，刀具表面应力和温度随着Y方向振动幅度和频率增加而增大和升高，刀具磨损加重；当X方向和Y方向均存在振动时，刀具表面应力和温度也随着振动幅度和频率增加而增大和升高，刀具磨损严重。利用实际切削试验对有限元分析结果进行验证，发现振动对刀具磨损影响较大，与有限元分析结果基本一致。      

Improvement of viscoelastic damping in nickel aluminum bronze by indium-tin

Reduction of the vibration noise from submarine propellers is of interest in naval operations. Such an objective can be achieved via the use of materials with the ability to dissipate energy of vibration by means of heat, i.e. high damping materials. An additional problem is that the extreme hydrostatic pressure environment of a submarine requires the chosen material to exhibit considerably high stiffness. Most materials demonstrate a compromise between the two properties, i.e. stiffness and damping. This paper aims to discuss research into high stiffness and high damping materials conducted using a dynamic mechanical analyzer (DMA) under variations of testing temperature, frequency, and strain amplitude. Alloys of nickel aluminum bronze and indium tin are the subjects of this study. Defect damping represents a large portion of the overall damping properties of the nickel aluminum bronze while increasing indium content is shown to boost the damping properties of the indium tin alloy. The study then continues with the development of a new material that combines both indium alloying and defects introduction into the nickel aluminum bronze alloy. The new alloy is observed to have high damping, as measured in its high tan δ, with minimum reduction of the stiffness |E*|.     

Thermomechanicai coupling simulation and experimental study in the isothermal ECAP processing of Ti-6Al-4V alloy

The thermomechanical coupling simulation of the isothermal equal channel angular pressing(ECAP)of Ti-6Al-4V alloy was conducted.The effect of processing parameters,ECAP pass number and the residual billet on the effective strain,stress and temperature distribution was investigated.Based on the coupling simulation results,it is found that the shear factor,ram speed,deformation temperature,channel intersection angle and residual billet significantly affect the ECAP deformation behaviors.Meanwhile,the experimental study of the isothermal ECAP process of Ti-6Al-4V alloy using route C,in which the repeated rotation angle around the longitudinal billet axis before reinsertion in channel intersection angle of 120°.Furthermore,a large amount of recrystallization occurs and some prior α phase grains grow in the post-ECAP process of Ti-6Al-4V alloy.The yield strength of post-ECAP Ti-6Al-4V alloy increases compared with that of as-received Ti-6Al-4V alloy.     

Ti600合金的高温变形本构关系

采用GW-1200A型控制器配合高温加热炉在WDW-300电子万能试验机上通过等温压缩实验研究了Ti600合金在温度为25?800℃、应变速率为10-4和10-3 s-1条件下的热变形行为,获得了该合金在变形过程中的真应力-真应变曲线,建立了该合金的高温本构关系。结果表明:Ti600合金在较高的温度(600和800℃)下流变应力随应变速率增大而增大,在较低温度(25和300℃)时变化不太明显。在一定的应变率条件下,随着温度升高流变应力降低。考虑到Ti600合金在不同温度下的真应力-真应变曲线随温度变化的发展趋势,建立了修正的井上胜郎高温本构关系,与实验结果对比验证了模型是可靠的。通过扫描电镜(SEM)观察发现,在室温准静态压缩条件下Ti600合金的断裂形式以脆性断裂为主,同时在局部区域出现韧性断裂特征。