- 期刊
表面腐蝕生成物對熱處理AA7050鋁合金在鹼性3.5% NaCl水溶液中應力腐蝕之影響
Effect of Pre-immersion on the SCC of Heat-treated AA7050 in an Alkaline 3.5% NaCl
摘要
Aluminum alloy AA7050 heat-treated variously (i.e., T6, T73, RRA, OP1, and OP2) was pre-immersed in an alkaline (pH=12) 3.5% NaCl for 240 hours, and the effect of the preimmersion on its stress corrosion cracking (SCC) in the same environment was of interest. This effect was investigated using slow strain rate test (SSRT) under electrochemical monitoring. The corrosion products on the specimens were analyzed through Fourier-transform infrared spectrometer (FTIR) and electron spectroscopy for chemical analysis (ESCA). For the specimens experienced the same heat treatment, the pre-immersed ones revealed higher SCC-resistance than those without pre-immersion. The enhancement of SCC-resistance varied with the type of heat treatments, i.e., T6 (43%)＞RRA (27%)＞OP1 (18%)＞OP2 (14%)＞T73 (11%). Analysis of the corrosion products benefited to delineate the enhancement in SCC-resistance. Examination of through scanning electron microscopy (SEM) equipped with energy dispersive spectrophotometer (EDS) demonstrated that the corrosion products consist of elements such as Al, Zn, Mg, Cu and oxygen. Resulting from FTIR spectra, the corrosion product on T6 specimen enriched more copper hydroxide than on OP1 and RRA specimens. Analysis of ESCA exhibited that pre-immersion leads to the formation of CuO in the corrosion products of T6 and a mixture of CuO and CuCl2 in the corrosion products of OP1 and RRA..
並列摘要
Aluminum alloy AA7050 heat-treated variously (i.e., T6, T73, RRA, OP1, and OP2) was pre-immersed in an alkaline (pH=12) 3.5% NaCl for 240 hours, and the effect of the preimmersion on its stress corrosion cracking (SCC) in the same environment was of interest. This effect was investigated using slow strain rate test (SSRT) under electrochemical monitoring. The corrosion products on the specimens were analyzed through Fourier-transform infrared spectrometer (FTIR) and electron spectroscopy for chemical analysis (ESCA). For the specimens experienced the same heat treatment, the pre-immersed ones revealed higher SCC-resistance than those without pre-immersion. The enhancement of SCC-resistance varied with the type of heat treatments, i.e., T6 (43%)＞RRA (27%)＞OP1 (18%)＞OP2 (14%)＞T73 (11%). Analysis of the corrosion products benefited to delineate the enhancement in SCC-resistance. Examination of through scanning electron microscopy (SEM) equipped with energy dispersive spectrophotometer (EDS) demonstrated that the corrosion products consist of elements such as Al, Zn, Mg, Cu and oxygen. Resulting from FTIR spectra, the corrosion product on T6 specimen enriched more copper hydroxide than on OP1 and RRA specimens. Analysis of ESCA exhibited that pre-immersion leads to the formation of CuO in the corrosion products of T6 and a mixture of CuO and CuCl2 in the corrosion products of OP1 and RRA..