| This study was conducted on the specific damping capacity(SDC) of rolled Zn-22Al alloy(Superplastic Zinc, SPZ). SDC is found to increase with increasing reduction ratio, because of the microstructure change from network to particle type. SDC is very sensitive to the change of frequency, so that the variation of frequency with reduction ratio was investigated. Frequency is almost constant with reduction ratio. But the frequency is decreased when the specimen is heat treated. SDC of both as-rolled and heat treated sheets are increased largely with increasing temperature. That is, SDC is about 11~14% at room temperature, but 50% at 130℃. This reason is considered as follows. Relaxation time τ subjects to thermal activation process and SDC becomes a maximum(has a peak) when ωτ is equals to 1 in SDC =△0ωτ/ (l +ω2τ2). |
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