熱處理型鋁合金的機械性質與熱的關係相當密切，討論溫度對於鋁合金機械強度的研究已經非常完整，但對於電流與機械性質的關係則沒有太多的討論。本研究以高強度的7075-T7351鋁合金，施以電流密度為1000A/cm2之直流通電實驗，探討其機械性質以及微觀組織與通電之間的關係。
實驗結果顯示，通電後的7075-T7351鋁合金拉伸變形行為的變化與銅原子及鋁原子的電遷移有關。通電過後的試片負極端硬度明顯下降，拉伸降伏強度也大幅下降；以電子微探儀(EPMA)分析通電後試片顯示通電負極端鋁原子密度小於正極端，可確認經過通電試驗後，鋁原子發生電遷移之情形。由於單純溫度的影響不會造成試片兩端的差異，可說明高強度7075鋁合金塊材確實會在通電過程中，發生電遷移現象。
通電後試片的拉伸曲線呈現鋸齒狀抖動，而通電前則沒有這種現象，若是對通電後的試片進行人工時效處理再進行拉伸，則鋸齒狀抖動消失。在7075鋁合金中，固溶在基地的合金元素在足夠的濃度下，會在變形時與差排發生交互作用，而在拉伸曲線上表現出鋸齒狀抖動，此即為動態應變時效。由通電後試片拉伸曲線上出現的鋸齒狀抖動可知，通電會造成原本析出的合金元素重新固溶回基地中，而施以人工時效處理後，又會再度析出，造成固溶在基地裡的合金元素濃度不足，拉伸曲線的鋸齒狀抖動現象又消失。
微觀組織的觀察中，通電後正極觀察到含銅量非常高(>80wt％)的顆粒。在負極的觀察中則沒有類似的顆粒存在。因此可知通電的過程中銅原子由負極往正極電遷移，如此會造成析出強化相分解，而使材料強度下降，且析出物分解後合金元素會重新固溶回基地，即為通電後試片拉伸時所表現出動態應變時效行為之原因。

There are few studies on the relationship between current load and strength of heat treatable aluminum alloys, while the great influence of heat on the performance of these high strength alloys is well known. The DC’s effect of on the mechanical property and microstructure of the high strength Al-Zn-Mg-Cu (7075-T7351) alloy is investigated in this research.
The decreases in the hardness and yield strength are notable, after a 1000A/cm2 DC loading for 5 and 300 minutes. The electromigration of metal atoms during the current loading is considered the major cause, which is observed by EPMA (Electron Probe Mapping Analysis). The difference in the drops of hardness between the cathode end and the anode end of the 7075 specimens after the DC loading is definitely caused by the electric current but not only by the heat.
The similar serration phenomena observed in the DC loaded and the solution treated specimens show that the solute atoms solves back into matrix during the current loading. The serrated flow, again, disappears in the specimens which undergo artificial aging after DC loading. As expected, the 7075-T7351 specimen shows no serrated flow in tensile stress-strain curve. The occurrence of serrated flow indicates that dynamics strain aging takes place in tensile deformation.
The particles containing about 80 wt% Cu can be observed only near the anode end of DC loaded specimens. The Cu atoms migrate to anode end due to the current load, and therefore the precipitates are dissolved. The dissolve of the precipitates will cause a decrease in the strength of 7075-T7351. It also makes solute atoms solve back into matrix as dynamics strain aging occurs in current loaded specimens.

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