本研究探討鋅含量與微觀組織對鋁鋅合金系統之機械性質、共振阻泥、共振破壞行為的影響。
將鑄造與擠形試料於室溫、初始應變速率8´10-4s-1條件下，進行拉伸試驗。根據拉伸試驗結果可知，鑄造與擠形試片之變形阻抗與鋅含量之間存在正相關性，且擠形試料之變形阻抗較同成分之鑄造試片高;鑄造試料之總延伸率與均勻延伸率與鋅含量之間存在負相關性，擠形試料以Al-11wt%Zn具有最佳總延伸與均勻延伸率，約為180%左右。拉伸破斷面特徵大多為延性破壞之酒窩狀組織，但Al-16wt%Zn之擠形試料卻以脆性沿晶破壞形式出現。
振動阻尼值的量測結果顯示，鑄造與擠形試片之對數衰減率隨鋅含量之增加而上升。
在共振過程中，試片末端偏移量的變化與振動次數具有相關性，並可畫成D-N曲線。D-N曲線可分成三區：在第一區試片具有加工硬化的現象，偏移量隨振動次數增加而上升;第二區偏移量維持一定，主裂縫在此區傳播;第三區振動台振動頻率以偏離試片之共振頻率，偏移量隨振動次數增加而下降。根據本實驗結果可將D-N曲線定義為三種型態：A型，以第二階段(偏移量平台區)、第三階段(偏移
量衰減區)為主 ; B型，包含第一階段(偏移量增幅區)、第二階段(偏移量平台區)及第三階段(偏移量衰減區) ; C型，主要由第一階段（偏移量增幅區）與第三階段（偏移量衰減區）所構成。
裂縫路徑觀察的結果顯示，鑄態試片裂縫主要以穿晶形式傳播;擠形試片裂縫沿晶界傳播之比率隨鋅含量增加而上升。共振壽命方面的研究顯示，Al-Zn合金之耐振動破壞阻抗主要受到裂紋傳播阻抗的影響，Al-16wt%Zn擠形試片具有最佳共振壽命。

The effects of Zn content and microstructure on the mechanical property, damping capacity, and resonant vibration fracture of Al-Zn alloys were investigated.

The tensile tests for the as-cast and extruded specimens were performed under initial strain rates 8´10-4s-1, and the tensile temperature was R.T. Experimental results indicated that the flow stress of as-cast and extruded specimens had a positive proportion to Zn content, and the flow stress of extruded specimens were higher than as-cast specimens which were the same Zn content. The total elongation and uniform elongation of as-cast specimens had a negative proportion to Zn content. In particular, Al-11wt%Zn alloy of extruded specimens had maximum total elongation and uniform elongation. Most of the tensile fracture surface of all specimens displayed typical dimple patterns, but it was a brittle inter-granular fracture in Al-16wt%Zn of extruded specimens.

Measurements of the logarithmic decrement d for the as-cast and extruded specimens were increased with increasing Zn content.

The deflection amplitude in resonance can be classified into three stages as a function of vibration cycle. In stage I, the deflection amplitude increases with the number of vibration cycles. The hardness of specimen also increases with vibration cycle during this stage. The test specimens possess a distinct plateau stage of maximum deflection amplitude in second stage. In stage III, the frequency of specimen diverges from the resonance condition. The deflection amplitude decreases with increasing vibration cycles. Experimental results indicate the D-N curves can be classified into three types. For A type, the curve is formed by stage II and stage III. For B type, the curve is formed by stage I、stage II and stage III.
For C type, the curve is formed by stage I and stage III.

In the observation of crack paths, for the as-cast specimens, the crack mainly propagates through grains. The proportion of crack which is propagates through grain boundary in extruded specimens was increases with increasing Zn content. In current study, the vibration resistance of Al-Zn alloy is mainly influenced by crack propagation resistance. The resonant vibration life of Al-16wt%Zn of extruded specimens was best.

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