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題 名 | 熱處理對超塑性7475鋁合金腐蝕性質的影響=The Effect of Heat Treatment on the Corrosion Behavior of a Superplastic 7475 Aluminum Alloy |
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作 者 | 蔡騰群; 張錦泉; 莊東漢; | 書刊名 | 材料科學 |
卷 期 | 29:4 1997.12[民86.12] |
頁 次 | 頁242-253 |
分類號 | 472.5 |
關鍵詞 | 超塑性; 動態極化; 腐蝕電位; 孔蝕電位; 腐蝕電流密度; 鈍態電流密度; 沿晶腐蝕; Superplasticity; Potentiodynamic polarization; Corrosion potential; Pitting potential; Corrosion current density; Passive current density; intergranular corrosion; |
語 文 | 中文(Chinese) |
中文摘要 | 本研究是取超塑性7475鋁鋅鎂合金,施以不同的時效熱處理後,利用動態極化曲 線掃描試驗來探討各種時效處理條件對腐蝕性質的影響。結果發現固溶淬火後的熱處理條件 (W) 試片,具有較活性的腐蝕電位與孔蝕電位、較大的腐蝕電流密度與鈍態電流密度及較嚴 重的沿晶腐蝕敏感性; 當時效處理程度由 W 熱處理條件增加至 T6 熱處理條件後,由於固 溶在基地內的 Zn、Mg 溶質原子含量會隨析出程度的增加而減少,而造成腐蝕電位與孔蝕電 位趨向貴性、腐蝕電流密度與鈍態電流密度減少及沿晶腐蝕敏感性的降低;當過時效處理程 度增加至 T73 熱處理條件,則因 MgZn �祖R出物體積分率的增加, 而導致與 T6 熱處理條 件相較,其腐蝕電位趨向貴性、孔蝕電位趨向活性及腐蝕電流密度與鈍態電流密度增加。而 晶界析出物尺寸的增加與分佈密度的減少及晶界偏析降低等因素, 造成 T73 熱處理條件具 有極佳的抗沿晶腐蝕性。 |
英文摘要 | The influence of different heat treatments upon the corrosion behavior of a fine grained 7475 Al-alloy plate has been investigated by using potentiodynamic polarization technique. In cold water quenched (W temper)condition. which has been shown to possess more active corrosion and pitting potentials, larger corrosion and passive current densities, and more severe intergranular corrosion. Increasing the degree of aging from the W to the peakaging T6 tempered condition would result in the decrease of the concentration of Zn and Mg alloying elements in the matrix because of the precipitation of MaZn ��. This leads the corrosion and pitting potentials to become more noble, the decreases of the corrosion current density, passive current density and the susceptibility of intergranular corrosion. Overaging to T73 tempered condition would increase the volume fraction of MaZn �� precipitates. Therefore, the T73 tempered specimen possessed more noble corrosion potential, more active pitting potential, and larger corrosion and passive current densities than could T6 tempered specimen. The higher intergranular corrosion resistance of the T73 tempered specimen is due to the increase of the size grain boundary precipitates (GBPs), the decrease of the distribution density of GBPs and the reduction of the segregation of solute atoms. |
本系統中英文摘要資訊取自各篇刊載內容。