本研究探討通電對於1050鋁合金內部的顯微結構及機械性質之影響。實驗將1050鋁合金薄試片施加2~10 kA/cm2之電流密度，通以直流電時間0~6小時。實驗結果顯示於8 kA/cm2電流密度下，隨通電時間增加，試片的最大抗拉強度(UTS)具有先下降而後上升的現象，由電子背向散射衍射分析(EBSD)微結構，可見通電2小時內晶粒尺寸上升並持平，晶粒取向逐漸轉為<111>。以HRTEM分析試片內部差排密度(Dislocation density)，計算之差排密度由初始的1016 m-2於通電2小時內下降至1015 m-2並於通電2~4小時升接近1017 m-2，對應了機械性質的變化。推論通電對試片造成之影響牽涉兩種機制：其一為通電使促進差排移動、結合，並產生回復現象，降低差排密度以致機械強度下降；其二為電子風力(electron wind)破壞晶格結構，製造大量缺陷與差排，將使差排密度上升，機械強度增加。當差排累積大量後，因再結晶驅動力(driving force)增加，又驅使差排相互結合與消除，使機械強度再度下降。

This study investigated the effect of electric current on the microstructure and mechanical properties of 1050 aluminum alloy. The strip specimens were subjected to 2~10 kA/cm2 D.C. for 1~6 hours. The specimens were rapidly quenched with liquid nitrogen after current stressing to freeze the microstructure for investigation. The results show that under 8000 A/cm2 D.C. current, the UTS would decrease and then increase with the increasing current time. EBSD analysis indicated that the orientation turned to <111> direction after current stressing. HRTEM images were applied to investigate the appearance of dislocations and to calculate the dislocation density. The dislocation density change from 1016 m-2 to 1015 m-2 in the initial 2 hours and then increase to 1017 m-2 during 2~4 hours. This trend was correspondent with the strength change after D.C. current stressing. In this study, the electrical current appeared to affect the aluminum alloy through two aspects: the lattice damage caused by electron wind and the recovery induced by electrical current. The specimen with strain and dislocations before D.C. current stressing had high strain energy. When the electrical current applied, the recovery induced by electrical current would promote dislocations rearrangement and annihilation. As the interior dislocations were eliminated by recovery, the strength decreased. On the other hand, the electron wind caused defects such as dislocations and destructed the lattice structure. With dislocations accumulation during the current stressing, the mechanical strength would increase due to work-hardening. Specimen with high dislocation density, in which the driving force of recovery was large enough, would initiate recovery again and resulted in the decrease in strength.

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