【作者】 赵玉珍；

【导师】 高庆；

【作者基本信息】 西南交通大学 ， 固体力学， 2004， 博士

【摘要】 阻尼减振是以动力学和材料科学为基础的一门综合性技术，是工程结构或构件减振降噪的有效手段。为了更好地提高结构材料的阻尼减振能力，要在高阻尼结构材料的基础理论和制备工艺上实现新的突破。本文系统地介绍了Zn-27Al合金的铸造、变质和固溶时效处理工艺；详细分析了不同工艺下的微观组织结构的特点；在微观分析的基础上重点研究了Zn-27Al合金的阻尼机理；对Zn-27Al合金的力学性能和阻尼性能进行分析测定，在保证材料具有良好的综合力学性能的基础上，较大地提高合金的阻尼性能；对试验数据进行分析拟合导出反应金阻尼值与温度、频率的关系式；在研究微观机理的基础上，从微观层次首次给出定量计算合金阻尼值的近似表达式；对Zn-27Al高阻尼合金构件进行振动试验分析和有限元模态分析。本文的主要研究工作如下： 1．基于对力学性能和阻尼性能的综合考虑，自制了Zn-27Al铸态合金，通过控制凝固参数和铸造工艺，很好地控制了铸态合金的成分和组织。对合金的凝固过程进行了深入分析，对凝固组织进行了研究。 2．在Zn-27Al合金中加入微量钛和稀土元素进行变质处理，分析了变质后合金的微观组织结构发生的变化以及对合金的性能的影响，对各种微量元素的变质细化机理进行了研究。 3．Zn-27Al合金经过稀土和钛变质后，进一步进行了350℃保温1小时后水淬的固溶处理，并长时间室温时效。热处理能消除合金铸造产生的非平衡网状共晶体，消除成分偏析，使组织均匀化。水淬时，冷速大，单相固溶体保留至室温，在随后的自然时效过程中，析出细粒状的α和η相，且相界面为可动非共格界面。从而能够进一步提高合金的阻尼性能。 4．对铸态和变质固溶时效处理后的Zn-27Al合金的力学和阻尼性能进行比较，深入研究变质固溶时效后合金阻尼性能提高的微观组织影响因素。根据实验结果，研究了合金的阻尼性能对环境因素(温度、频率和振幅)的敏感性：Zn-27Al合金的阻尼性能随温度的升高而增大；随着频率的增大而减小；不随振幅的变化而变化，温度和频率对变质固溶时效后合金阻尼性能的影响更为突出。 5．对铸态和变质固溶时效后Zn-27Al合金的阻尼值进行拟合分析，给出合第日页西南交通大学博士研究生学位论文 金阻尼值随温度、频率变化的拟合公式，比较合金阻尼值拟合计算结果与 试验结果，表明所给出拟合公式是合理的。并由此公式可计算出材料在工 作温度范围内任一温度和频率下的阻尼值。6.Zn-27AI合金属于复相型阻尼合金，通过对Zn一27AI合金微观组织的分析 和对合金阻尼特性的研究，提出了变质固溶时效处理提高合金阻尼的微观 机理。zn一27AI合金的力学阻尼(内耗)是一种线性滞弹性弛豫的动滞后型 阻尼，其耗能机制是由于晶界和相界的粘滞性滑动，以及Q相的局部微塑 性变形。因而，合金的内耗值大小主要决定于界面的可动性及可动界面的 面积。上述微观机理充分揭示了变质固溶时效后的Zn一27AI合金由于组织 细化及非共格可动界面的增多，使合金阻尼大大提高的原因。7.采用透射电镜，在研究高阻尼Zn一27AI合金微观机理的基础上，从微观 层次首次给出定量计算材料内耗值的近似表达式，与实验结果的比较表明 了该表达式的适用性。8.论文进行了不同材料简单结构件的减振性能研究。把铸态、变质固溶时效 Zn一27AI合金以及常用普通A3钢加工成简单结构件，从有限元分析和试验测 试两个方面对比研究了三种材料结构件在实际振动条件下的减振性，对此分 析表明:(l)用Zn一27AI合金加工成结构件，其减振性能远远大于工程上常用 的普通A3钢。经过变质固溶时效处理后的Zn一27AI合金结构件，其结构件减 振性能更好。(2)用实验测试和有限元分析两种方法对不同材料结构件进行 减振分析，二者所得结构件的固有基频值与阻尼值基本是一致的。说明通过 计算模型对阻尼材料结构件进行减振分析是可行的。(3)通过对三种材料阻 尼值与相应材料结构件振动试验所测阻尼值比较，说明高阻尼材料的材料阻 尼性能在结构阻尼中占重要比例。因此采用高阻尼材料以及提高材料的阻尼 性能对提高结构减振性有重要意义。关键词:高阻尼Zn一27AI合金;铸造;变质;固溶时效;内耗;阻尼机理;结构件:模态分析更多还原

【Abstract】 Vibration damping which is an effective application in vibration and noise control is a field of comprehensive technology on the basis of dynamics and material science. In order to improve the capability of vibration damping of structure materials, innovation must be carried out from the aspect of basic theory and preparation techniques. The techniques of founding, modification, solution heat treatment and ageing are systematically introduced in this paper. Microstructures of Zn-27A1 alloy are analyzed. The damping mechanism of Zn-27A1 alloy was studied in detail. The mechanics and damping properties of Zn-27A1 alloys were mensurated, and the damping properties of Zn-27A1 alloys got a farthest advancement on the basis of having good mechanics properties. Based on the test-data, the linear fitting expression for the damping of alloy is obtained, which shows the relationship between the damping properties of alloy, the temperature and the frequency. On the basis of this study of the damping mechanism, the approximate expression of quantitatively calculating the damping has been derived for the first time. The vibration test and modal analysis method were used to analyze the structures made of Zn-27A1 damping alloy. The main work is as follows:1. By considering both compositive mechanical properties and damping properties, the foundry Zn-27A1 alloy was made, the component and microstructure of the foundry alloy were controlled by controlling the solidification parameters and casting techniques. The solidification process and microstructures were studied.2.The alloy was modified by adding trace Ti and rare earth(RE) elements, the microstructure and properties of Zn-27A1 alloy modified by Ti and RE were analyzed. The modification micromechanism was studied.3. The Zn-27A1 cast-alloy modified by Ti and Re was solution heat treated (350 X lh)and then aged naturally. The net structure after un-equilibrium solidification and component asymmetry can be eliminated by heat treatment. The microstructure of alloy was refined by solution treatment and natural ageing. The single-phase structure kept to room temperature for water quench and speediness cooling . Thesingle-phase structure would transit granular a and n phases, and their phase interface are incoherent. The above made the damping properties of Zn-27A1 alloy getting advancement.4. The mechanical and damping properties of the foundry Zn-27A1 alloys and the Zn-27A1 alloys after modificition, solution heat treatment and ageing were Compared. The effect of microstructure to the damping properties of alloy was studied. The damping properties of Zn-27A1 alloy under various working conditions such as temperature, amplitude and frequency were studied. The research results show that: the damping properties of alloy are increased with increasing temperature, increased with the reduced frequency, and was independent of amplitude. The effect of the temperature and frequency on the damping properties of Zn-27A1 alloys after modification, solution treatment and natural ageing was more prominent.5. By the linear fitting analysis for the damping properties of the foundry Zn-27A1 alloys and the Zn-27A1 alloys after modification, solution treatment and natural ageing, The fitting expression of the variation of the damping of Zn-27A1 alloy with the temperature and frequency was obtained. The comparison the results from experiment with the results from linear fitting showed that the expression was comparatively right. The equation can be used to predict the damping properties of alloy under any temperature within the scope of the working temperature and frequency.6. The Zn-27A1 alloy is a multi-phase alloy. The damping mechanism of high-damping Zn-27A1 alloy was studied by analyzing the micostructures and the damping properties. The damping(internal friction) of Zn-27A1 alloy is linear, reversible, anelastic and dynamic hysteresis mechanical damping. The energy dissipation results from the viscous sliding between grain boundaries or phase interfaces and micro-plastic deformation of a ph更多还原