Research On Damping Property And Damping Micromechanism Of High Damping Zn-27Al Alloy

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...