论文部分内容阅读
采用双悬臂梁(DCB)试样,并通过阴极极化、扫描电镜(SEM)、透射电镜(TEM)和飞行时间二次离子质谱(ToF-SIMS)分析等手段,研究了不同时效状态下7050铝合金在3.5%Na Cl水溶液中的应力腐蚀行为。结果表明:7050铝合金时效后的应力腐蚀敏感性(Iscc)变化规律为:Iscc欠时效(135℃×8 h)﹥Iscc峰时效(135℃×16 h)﹥Iscc过时效(135℃×24 h)。阴极极化电位E=-1100 m V时,合金的Iscc增加,DCB试样裂尖处氢离子流强度变大,氢在晶内扩散程度加深。微观组织分析表明:随着时效时间的延长,7050铝合金晶界析出相明显粗化,并且呈不连续分布。
A double-cantilever beam (DCB) sample was used. The effects of different aging conditions, such as 7050 Stress Corrosion Behavior of Aluminum Alloy in 3.5% NaCl Solution. The results show that the stress corrosion susceptibility (Iscc) of 7050 aluminum alloy after aging is: Iscc under aging (135 ℃ × 8h)> Iscc peak aging (135 ℃ × 16h)> Iscc over aging (135 ℃ × 24 h). When the cathodic polarization potential E = -1100 mV, the Iscc of the alloy increases, the strength of the hydrogen ion current at the crack tip of the DCB sample becomes larger, and the diffusion of hydrogen in the crystal becomes deeper. The microstructure analysis showed that the grain boundary precipitates of 7050 aluminum alloy obviously coarsen with discontinuous distribution as the aging time prolongs.