热处理对Mn-Cu合金微观组织和阻尼性能的影响

通过X射线衍射仪（XRD）、扫描电子显微镜（SEM）和动态机械热分析仪（DMA）的相结构、微观结构和阻尼性能的测试结果,研究了热处理工艺对轧制态CuMn50合金的微观组织和阻尼性能的影响。结果表明合金的阻尼性能随着应变振幅先缓慢增加而后迅速增加;随着冷速提高,Mn-Cu合金开始出现晶粒,阻尼性能降低,缓慢冷却有利于富锰区的产生,起到了时效的作用;炉冷时效后,阻尼性能进一步提高,时效时间对炉冷试样的微观结构和阻尼性能没有影响;水冷时效后,随着时效时间的增大,合金的晶粒先变得粗大随后析出第二相α-Mn,阻尼性能先增大到峰值随后略为减低,840℃固溶0.5h又420℃时效8h后,合金的阻尼性能达到最好。     

时效温度对Mn20Cu5Ni2FeCe合金组织性能的影响

MnCu合金通过合适的热处理,可以获得出色的阻尼性能,同时还具有优良的力学性能。本文采用真空熔炼制备了Mn20Cu5Ni2FeCe合金。采用XRD、TEM及DMA等分析测试手段,研究了时效温度对合金微观组织及阻尼性能的影响。结果表明,固溶态合金具有单相fcc面心立方结构,其阻尼能力tanδ值小于0.01,不具备明显的阻尼能力。时效后合金发生调幅分解,析出富Mn相,合金的阻尼能力显著提升。当时效温度为400℃时,合金的tanδ值达到0.045,呈现出高阻尼能力。不同温度条件下合金阻尼能力测试结果表明,在-50~80℃温度范围内,合金的阻尼能力随温度的降低明显升高,表明该阻尼合金在低温下具有重要的应用前景。     

稀土元素Ce对Mn-Cu合金阻尼性能的影响

对用稀土Ｃｅ 改性的高阻尼Ｍｎ Ｃｕ 合金的阻尼性能与微观组织进行了研究。结果表明,添加稀土元素Ｃｅ,不仅能显著提高Ｍｎ Ｃｕ 合金的阻尼性能,而且能缩短达到峰值阻尼性能的时效时间,同时还抑制了过时效时阻尼性能的下降。     

稀土对Fe-17.5Mn合金阻尼性能的影响

利用倒扭摆仪对比研究了Fe-17.5Mn二元合金和Fe-17.5Mn-0.3Mm(富铈混合稀土)合金的阻尼性能,并借用Olympus显微镜观察分析了合金的微观组织.研究结果表明,在1000℃保温1h后水淬状态下,Fe-17.5Mn-0.3Mm合金的阻尼性能明显优于Fe-17.5Mn二元合金.在微量稀土元素的作用下,Fe-17.5Mn-0.3Mm合金中相对于Fe-17.5Mn二元合金其马氏体数量较多、板条较细薄,板条变薄且单位体积内界面面积增加,使振动的微观阻尼源增多,导致阻尼性能提高.     

阻尼镁合金的研究现状与发展趋势

阐明了镁合金的阻尼机理及应变振幅、频率、温度对镁合金阻尼性能的影响.综述了当前改善镁合金阻尼性能的主要方法,如添加合金元素、控制变形工艺、热处理、控制晶粒尺寸和取向、添加增强相.指出通过添加新的增强相和合金元素,引入位错阻尼之外新的阻尼产生机制,解决阻尼性能与力学性能的矛盾,将是未来高性能阻尼镁合金材料研究的重要方向,而且,产品外形结构设计与阻尼性能的关系也是值得关注的一个新研究方向.     

铝-铜系铸造合金热强性的研究

Al-Cu系合金是现在使用的最主要的热强铸铝材料。关于各种合金化元素对Al-Cu系铸造合金热强性的影响,及合金在高温下的组织变化,国内外已进行了广泛的研究,并在这些研究工作的基础上创制了能在300℃以上工作的几种合金,如ZL-401,АЦР-1,АЛ33,RR350等。在有关文献中侧重研究了在高温下较短时间内的组织变化情况,对长时间热暴露条件下组织变化及其对性能的影响则研究得不够系统。我们在研制新型热强铸造铝合金的过程中,就某些元素对Al-Cu系铸造合金热强性的影响及其在长期热暴露过程中,显微组织及力学性能的变化作了一些探索工作。 一、试验方法和结果     

Si对AM50力学性能和高温蠕变性能的影响

在基体合金AM50中分别加入Si和Ca,研究了Si和Ca对AM50-xSi合金的微观组织、力学性能及蠕变性能的影响.结果表明:加入Si后,合金高温蠕变性能随Si量的增加而增加并超过了AS41的水平;在AM50-xSi中加入微量Ca以后,合金中的Mg2Si相得到细化,从汉字状转变成颗粒状,室温及150℃拉伸性能明显提高.     

均匀化及时效处理对Al-Zn共析阻尼合金组织及性能的影响

采用井式电阻炉熔炼及真空感应熔炼的方法制备名义成分为50Al-48.9Zn-1Ti-0.1Ce(原子百分数，at%)的合金，然后在380℃保温20 h进行均匀化处理，并于150℃下分别进行1 h、2 h、4 h、6 h, 10 h的时效处理，研究了均匀化及时效处理对Al-Zn共析阻尼合金组织和性能的影响。结果表明：均匀化处理消除了原铸态组织中的枝晶偏析，此时合金主要由α-Al分布在η-Zn基体上的共析组织所构成。然而经不同时间时效处理后的合金则主要由η-Zn分布在α-Al基体上的共析组织所构成。随着时效时间的增加，α-Al相含量逐渐增加(在均匀态下以及时效1 h、2 h、4 h、6 h、10 h后α-Al相的面积百分数分别约为16.1%、40.3%、47.2%、54.7%、60.1%、68.2%),共析组织不断粗化，且其形貌逐渐从不规则片层或颗粒状向近似等轴的颗粒状而转变。随着时效时间的延长，Al-Zn共析阻尼合金的阻尼性能不断上升(对于时效10 h后的合金试样，当应变振幅为8×10^-4时，其tanδ的值约为0.052)。与均匀态下的合金相比，短时时效处理后Al-...     

热处理对Fe-Cr-Mo合金阻尼性能的影响

通过DMA(动态热机械分析仪)测量Fe-Cr-Mo合金阻尼性能,研究了热处理工艺对Fe-Cr-Mo合金阻尼性能的影响;通过OM进行组织观察,并且分析了不同退火温度及冷却方式下合金微观组织对阻尼性能的影响。结果表明,合金在950~1150℃的退火温度范围内,随着退火温度升高,内耗增大;并且水冷后的合金内耗较小,炉冷后的合金内耗较大。分析认为,950℃热处理,内应力大,内耗较小,并且由于晶界多,磁畴壁移动困难,对应边敏感度小,而1150℃的热处理则内应力小,内耗较大,并且由于晶粒长大,晶界数量少,磁畴壁移动容易,对应边敏感度大。由于水冷冷速过快,造成成分不均,内应力较大,内耗小于炉冷的内耗。     

90°弯管磁过滤阴极弧沉积类金刚石膜的特性分析

利用动态机械热分析仪研究了四种镁硅合金的阻尼性能.研究表明：铸造镁硅合金具有良好的阻尼性能.并且体现出有别于纯镁的新阻尼特征,铸造镁硅合金具有较纯镁在更大应变振幅范围内的弛豫型内耗.由于Mg2Si对晶界的钉扎作用,界面阻尼峰出现在较纯镁更高的温度.少量钙的添加改善了Mg2Si析出的形态,但对阻尼性能的影响似乎不明显.     

Damping Capacity and Creep Resistance of Spray Deposited High Silicon Alloy ZA27

High Al zinc-based alloys are widely used in industry for their good ambient temperature mechanical properties and damping capacity. With the rise of service temperature its damping property increases but mechanical property decreases greatly Here two ways-alloying and spray deposition technique were adopted to improve the service temperature limitation of the alloy ZA27 in an effort to develop a new functional material with high damping capacity and good elevated temperature mechanical property. The effects of addition of 5 wt pct of Si Qn the damping behaviour and elevated temperature creep resistance of alloy ZA27 were investigated. The damping capacity, as well as the relative dynamic modulus, was measured at frequency of 1,4 Hz over the 303 to 573 K. No peak phenomenon was observed for the specimens tested in the temperature range of interest. Experimental results indicated that the damping capacity of the deposited material was 2.8 times higher than that of the cast one at 305 K. The ball hardness values were used to evaluate the creep property and the creep activation energy of the deposited material is 3.9~5.7 kJ per mol higher than that of the as-cast one. The creep rate formuIation was also derived. Finally, the operative damping and creep mechanisms were discussed in the light of the data obtained from its characterization of microstructure, damping capacity and creep reslstance     

Fe-Al合金内耗特征研究进展

原子缺陷对Fe-Al合金的力学和物理性能有重要影响,而内耗是对原子缺陷运动非常敏感的物理量.通过内耗特征的考查可以了解Fe-Al合金中原子缺陷的运动变化规律.对Fe-Al合金的内耗特征进行了分析,在总结与原子缺陷有关的3个内耗峰的主要特征和形成机理的基础上分析了以往研究中存在的争议和不足,并对今后的研究提出了建议.     

铸造镁硅合金组织和阻尼性能研究

利用动态机械热分析仪研究了四种镁硅合金的阻尼性能.研究表明:铸造镁硅合金具有良好的阻尼性能.并且体现出有别于纯镁的新阻尼特征,铸造镁硅合金具有较纯镁在更大应变振幅范围内的弛豫型内耗.由于Mg2 Si对晶界的钉扎作用,界面阻尼峰出现在较纯镁更高的温度.少量钙的添加改善了Mg2 Si析出的形态,但对阻尼性能的影响似乎不明显.     

Damping behaviour and mechanical properties of rapidly solidified Al–Fe–Mo–Si/Al alloys

In order to develop a new high damping aluminium alloy with strength and toughness for advanced aircraft structure application, rapidly solidified (RS) Al–Fe–Mo–Si/Al alloys were synthesized. The damping behaviour, mechanical properties and microstructures of the alloys were studied. Results showed that the damping capacities of RS Al–Fe–Mo–Si/10–15% Al alloys are stable between 7.0–10.0×10-3 at room temperature, which almost reach the high damping threshold, 10.0×10-3. At lower frequency (0.1–10 Hz) the damping capacity is decidely frequency and temperture dependent above 50°C, with lowest frequency and highest temperature resulting in the highest less factor. It was noted that mechanical properties of the Al–Fe–Mo–Si/10–15% Al alloys are both excellent at room temperature (b=536–564 MPa, =7.2–11.4%) and at elevated temperature (250°C: b=295–324 MPa). Analysis of microstructures reveal that the damping capacity arises from deformation of the pure Al areas, and strength at elevated temperature from the dispersion strengthening of intermetallic phase. © 1998 Chapman & Hall     

High damping properties of Mg–Si binary hypoeutectic alloys

The damping properties of as-cast Mg–Si hypoeutectic alloys with Si contents of 0.25, 0.5, 1 wt.% were investigated by Dynamic Mechanical Analysis (DMA), respectively. The results show that the Si content has an interesting influence on the damping properties due to the primary cyrstallized Mg₂Si. The damping capacities of high damping Mg–Si hypoeutectic alloys are strain amplitude strongly dependent while the strain amplitude weakly dependent part hardly appears due to very few Si dissolved in matrix. In addition, the damping measurement of Mg–0.5 wt.% Si alloy with increasing temperature was carried out and the grain boundary peak is detected.     

High damping in Fe-Ga-La alloys: Phenomenological model for magneto-mechanical hysteresis damping and experiment

Ferromagnetic high damping (FHA) alloys with a wide temperature range from-150 ℃ to 300 ℃ have unique application value in extreme environments.In the present work,the damping behaviors of Fe21Ga-xLa (x =0.12 wt.％,0.24 wt.％,0.47 wt.％,1.18 wt.％,and 2.33 wt.％La) alloys have been studied in detail,and a new phenomenoiogical model has been proposed.With the increase of La content,the Laves phase (LaGa2) in the matrix increases gradually,and the resistance opposing the domain movement increases as well.Combined with the results of synchrotron radiation X-ray diffraction,neutron diffraction,and magnetic domain observation,the resistance mainly comes from three parts: the average stress related to the lattice distortion of the matrix,the average stress related to the increasing area energy of domain walls (DWs),and the average stress related to the increasing demagnetization energy induced by the Laves phase.Different from the traditional method of reducing internal stress through annealing to improve the damping capacity,the proper internal stress barriers are necessary to Barkhausen jumps to dissipate energy.Therefore,proper doping to balance resistance and mobility of DWs is a reliable way to improve damping capacity.Meanwhile,for Fe-Al and Fe-Cr based Alloys,the new model also has a good fitting effect.This study provides a theoretical and experimental reference for improving the functional properties of ferromagnetic alloys.     

Physicomechanical properties of hardened copper-aluminum-zincβ-alloys with an intermediate structure

The hardenability for two hardening rates (water and air) and also the influence of diffusion transformation products on their damping capacity and mechanical properties are investigated in a broad concentration area of copper-aluminum-zinc system alloys. The general character of the change in microstructure and hardness with distance from the specimen surface is determined. The relationship of hardenability of alloys of the investigated system to their composition for two hardening rates is established. It is shown that with water hardening these alloys possess high and with air hardening insufficient hardenability. It is determined that formation in hardening in the structure of the alloys of products of diffusion decomposition of the matrix phase reduces their damping capacity and mechanical properties.Translated from Problemy Prochnosti, No. 11, pp. 66–70, November, 1992.     

High Damping Alloys and Their Application

Damping alloys show prospective applications in the elimination of unwanted vibrations and acoustic noise. The basic definitions and characterization methods of damping capacity are reviewed in this paper. Several physical mechanisms controlled by the alloy microstructure are responsible for the damping behavior in the damping alloys. Composite, dislocation, ferromagnetic and planar defect types are commonly classified for the alloys, which show the different damping behavior against temperature, frequency of vibration,amplitude of vibration and damping modes. Development of practically applicable damping alloys requires the higher mechanical properties and adequate workability, besides the high damping capacity. A new Mn-Cu damping alloy, named as M2052 alloy, is recently developed with possible industrial applications.     

铁基阻尼材料的发展现状和趋势

铁基阻尼材料是一种具有广阔应用前景的结构-功能一体材料,它具有优良的阻尼性能、综合力学性能和冷热加工性能。本文全面地介绍了铁磁型、孪晶型和复相型三类铁基阻尼材料的阻尼机制、研究和应用现状,并对铁基阻尼材料的发展趋势进行了展望。