ZL401合金的阻尼行为研究

对铸态ZL401合金进行了低温人工时效处理，利用低频内耗测试技术研究了合金的阻尼性能及实模量与应变振幅、频率和温度的关系，并与铸态合金进行了对比。发现合金阻尼与应变振幅及应变频率相关，随温度的提高而增大，且在低温和高温时合金阻尼与频率的关系出现了相反的变化。ZL401合金振动过程中实模量的亏损随频率的降低和温度的升高而增大。认为ZL401合金的阻尼行为是界面阻尼和位错阻尼二者效应叠加的结果，室温阻尼主要归功于位错阻尼，而高温阻尼主要归功于界面阻尼。     

Influence of impurities on damping properties of ZK60 magnesium alloy

The influence of impurities on damping capacities of ZK60 magnesium alloys in the as-cast, as-extruded and T4-treated states was investigated by dynamically mechanical analyzer at room temperature. Granato and Lucke dislocation pinning model was employed to explain damping properties of the alloys. It is found that reducing impurity content can decrease the amount of second-phase particles, increase grain size and improve damping capacity of the as-cast alloy slightly. The as-extruded alloy with lower impurity content is found to possess obviously higher damping capacity in the relatively high strain region than that with higher impurity concentration, which appears to originate mainly from different dislocation characteristics. The variation tendency of damping property with change of impurity content after solution-treatment is also similar to that in the as-extruded and as-cast states. Meanwhile, the purification of the alloy results in an evident improvement in tensile yield strength in the as-extruded state.     

Effect of small tensile deformation on damping capacities of Mg-1%Al alloy

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.     

镁合金的阻尼性能研究进展

介绍了镁合金的阻尼机理,在常温下其阻尼机制主要是位错机制,在高温条件下,由于晶界也参与滑移,所以除了位错阻尼外还有晶界阻尼的贡献。着重介绍了Mg-Al系、Mg-Zr系、Mg-Li系、Mg-RE系以及镁基复合材料的阻尼特性．讲述了热处理工艺对镁合金阻尼性能及其力学性能的影响。     

镁合金的阻尼性能研究进展

介绍了镁合金的阻尼机理。在常温下其阻尼机制主要是位错机制，在高温条件下，由于晶界也参与滑移．所以除了位错阻尼外还有晶界阻尼的贡献。着重介绍了Mg-Al系、Mg-Zr系、Mg-Li系、Mg-RE系以及镁基复合材料的阻尼特性．讲述了热处理工艺对镁合金阻尼性能及其力学性能的影响。     

高阻尼镁合金Mg-0.6%Zr和Mg-Ni中内耗峰分析

在高阻尼镁合金研究中,发现了与合金室温下高阻尼性能有关的宽的弛豫内耗峰,该峰为位错内耗峰;该峰是基面位错在热激活作用下运动与点缺陷（空位与溶质原子）相互作用产生。同时在高阻尼合金Mg-Ni和Mg-0.6%Zr中发现了晶界内耗峰。有必要指出的是合金的显微组织会影响晶界弛豫：随着Ni的质量分数增加,晶粒细化同时晶界内耗峰向低温处迁移;同Mg-0.6%Zr合金相比,加入少量的Y后,Mg-0.6%Zr-Y合金晶界弛豫峰向高温处推进。     

商业纯镁的低频阻尼性能

采用机械动态分析仪测试纯度为99.96%纯镁的阻尼性能随应变振幅和温度的变化。测试的纯镁包括具有不同晶体学取向的商业镁合金铸锭CPM1和CPM2以及重新熔炼的等轴晶纯镁CPM。商业纯镁柱状晶粒的织构显著影响纯镁的阻尼性能,而重新熔炼的纯镁获得等轴晶,从而避免铸造织构对其阻尼性能测试结果产生的影响。结果表明：在阻尼应变谱中,等轴晶纯镁的阻尼性能明显高于有柱状晶织构的纯镁。对于三种纯镁,阻尼温度谱在80和230°C分别存在两个阻尼峰P1和P2,这两个阻尼峰分别是由位错与点缺陷交互作用以及晶界运动引起的。     

镁及镁合金阻尼特性的研究进展

综述了镁及镁合金阻尼特性的研究进展及阻尼镁合金材料的研究现状,介绍了其阻尼性能的评价方法,阐明了其阻尼机制符合G-L位错钉扎模型、基面(0001)上的位错脱钉运动是造成镁合金在室温具有高应变振幅阻尼性能的主要原因,概述了应变振幅、温度、变形工艺、热处理、晶粒尺寸和取向以及合金元素对镁合金阻尼性能的影响.     

Effect of eutectic phase on damping and mechanical properties of as-cast Mg-Ni hypoeutectic alloys

Dynamic mechanical analysis (DMA) was applied to systematically investigate the low frequency damping properties of as-cast hypoeutectic Mg-Ni alloys. The results show that the as-cast hypoeutectic Mg-Ni alloys exhibit high damping capacities. The strain amplitude dependent damping curve has its own special characteristic, in which the damping is strongly related to the strain amplitude. The effect of the eutectic phase on damping and the mechanical properties of as-cast hypoeutectic Mg-Ni alloys were also discussed in detail.     

元素Y对Mg—Cu系合金的组织结构和显微硬度的影响

采用铜板空冷和铜辊甩带的方法，研究元素Y对Mg-Cu合金的组织结构和室温硬度的影响。研究表明：元素Y形成的化合物最终富集于枝晶网胞间。随着元素Y的添加，Mg-Cu二元合金试样的晶粒显著细化，显微硬度大幅提高。另外，在快速冷却条件下，Mg90 Cu5Y5试样的微观结构为微晶和非晶的夹杂，形成非晶的能力大大增强。     

元素Y对Mg-Cu系合金的组织结构和显微硬度的影响

采用铜板空冷和铜辊甩带的方法,研究元素Y对Mg-Cu合金的组织结构和室温硬度的影响。研究表明:元素Y形成的化合物最终富集于枝晶网胞间。随着元素Y的添加,Mg-Cu二元合金试样的晶粒显著细化,显微硬度大幅提高。另外,在快速冷却条件下,Mg90Cu5Y5试样的微观结构为微晶和非晶的夹杂,形成非晶的能力大大增强。     

预变形对Fe-Mn合金层错几率和阻尼性能的影响

探讨了Fe-Mn合金的高阻尼机制并采用G-L位错脱钉模型对其进行描述,同时通过测定层错几率,揭示了预变形(0-10%)对Re-Mn合金阻尼性能影响的本质.采用倒扭摆测试合金的阻尼性能,SEM和TEM观察显微组织,XRD测定物相体积分数和层错几率.结果表明,Fe-Mn合金的高阻尼性能来源于层错界面上Shockley不全位错的脱钉运动,实验结果很好地符合G-L位错脱钉模型;预变形量小于4%时,预变形处理虽然对合金的ε马氏体量没有太大影响,但明显增加了其层错几率,即Shockley不全位错的数量,合金的阻尼性能随变形量增加逐渐提高;预变形量大于4%时,由于ε马氏体和层错的相互交割,增大了Shockley不全位错的脱钉难度,所以合金的阻尼性能随变形量增加逐渐下降.     

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.     

热处理对Mg-6Zn-3Cu-0.6Zr合金阻尼性能的影响

采用扫描电镜(SEM)及能谱仪(EDS)、动态机械分析仪(DMA)研究了热处理温度和热处理时间对Mg-6Zn-3Cu-0.6Zr合金显微组织和阻尼性能的影响。结果表明:随着热处理温度升高,合金晶粒长大,晶界共晶体减少,合金阻尼性能提高;300℃热处理时,保温时间越长,晶界共晶体越少,晶内微小点状析出物越多,合金阻尼性能越好;当热处理工艺为400℃保温2 h时,合金阻尼性能最好,与铸态相比,其阻尼性能的提高超过一倍。不同热处理工艺对合金阻尼性能的影响规律可用G-L理论来解释。     

快速凝固-粉末冶金工艺制备高强阻尼铝合金的阻尼性能(英文)

采用快速凝固-粉末冶金(RS-PM)工艺制备两种不同类型的高强阻尼铝合金(LZ7),一种是直接挤压成型材,另一种是先挤压至棒材再轧制成板材。利用阻尼机械热分析仪(DMTA)在25~300°C下对其进行阻尼性能测试,利用光学显微镜(OM)、扫描电镜(SEM)、透射电镜(TEM)观察材料的微观组织。结果表明,随着温度的升高材料的阻尼性能提高,在300°C时板材的内耗值高达11.5×10-2,型材的内耗值达到6.0×10-2和7.5×10-2。轧制板材的内部析出相的颗粒形貌较挤压型材的析出相更规则,分布更均匀;板材中颗粒相与基体结合较疏松。基体与颗粒相结合情况的不同可以解释板材在高温阶段(120°C)阻尼性能优于型材阻尼性能的原因。     

Microstructure and hardness of binary Cr-Ta alloys

The dependances of the microstructure and hardness of the binary Cr-Ta alloys [ Cr-9.0, -9.2, -9.4, -9.6,-9.8, and -13.0 Ta] (mole fraction, %) were investigated. When Ta content of the alloy is less than 9.4%, there are primary dandrite grains of a Cr solid-solution phase existing in the matrix of Cr-Cr2Ta eutectic colonies in the alloy. Moreover, the regular polygon grains of the primary Cr2Ta Laves-phase are surrounded by the Cr-Cr2Ta eutectic colony in the hyper-euteetic Cr-9.4 96 Ta alloys. The scanning electron microphotograph shows that one of the Cr2Ta phase plates of an eutectic colony always connects with the primary Cr2Ta Laves-phase grain in a hyper-eutectic alloy. The eutectic colony size of Cr-Ta alloys decreases with increasing Ta. In addition, the macrohardness of Cr-Ta alloys is influanced by the chemical composition at room temperature. The binary eutectic Cr-Ta alloy presents the lowest hardness on a macrohardness scale.     

阻尼合金的研究发展现状

阻尼合金不仅拥有将机械振动能转化为热能并耗散掉的物理特性,而且具有较好的力学性能.如果将阻尼合金制造成零件应用到装备中将能有效控制设备运行时产生的振动和噪声,因此具有重要的工程价值.概述了复相型、位错型、孪晶型、铁磁型和Fe-Mn基阻尼合金的阻尼机制,归纳了影响上述合金阻尼性能的因素以及提高合金阻尼性能的途径.同时,对...     

EFFECT OF ANNEALING ON DAMPING CAPACITIES OF AS-CAST ZA27 ALLOY

1. Introduction Because ZA27 alloy possesses excellent mechanical properties and high damping capacities, it is widely used in industries. ZA27 alloy has good castability and can be easily cast into various castings by permanent mold casting. The solidification of ZA27 alloy in the permanent mold can be considered to be a nonequilibrium process, and thus the supersaturated aluminum-rich ! phase and unstable copper-rich phase may also be found in the solidified ingot. Those nonequilibrium pha…     

Precipitation and responding damping behavior of heat-treated AZ31 magnesium alloy

Microstructure observation and dynamic mechanical analysis were carried out to investigate the precipitation and responding damping behaviors of AZ31 magnesium alloy. All the strain amplitude-dependent damping curves of the aged alloys are located between the curves of solutionized and as-cast alloys, although they have different critical strain amplitudes. The G-L theory is employed to explain the damping mechanism involving the interaction between the dislocation and the precipitated phase. In addition, a damping peak is observed at temperatures close to 330 ℃ for AZ31 magnesium alloy, which is related to the β-Mg₁₇Al₁₂ phase dissolution.     

退火及置换元素对Fe-Cr-Al基合金阻尼性能及强度的影响

制备了Fe-13Cr-6Al（原子分数,%）及用2%的Mo、Mn和Nb分别置换Fe-13Cr-6Al中的Cr,用0.5%和1%的Cu分别置换Fe-13Cr-6Al中的Al共6种合金.测试了各合金的阻尼性能和强度,通过金相观察和内应力分析研究了退火温度、冷却方式及合金元素对这两种性能的影响.结果表明：随着退火温度的升高,Fe-Cr-Al基阻尼合金阻尼性能升高,强度降低;随炉缓冷合金的阻尼性能高于水淬合金的阻尼性能,而前者的强度低于后者;0.5%Cu置换Al降低了位错与溶质原子之间的交互作用,但是提高了合金原子与基体原子的弹性交互作用,使合金的阻尼性能和强度都得到了提高.