升温时效处理7075铝合金在含SRB模拟海水中的应力腐蚀行为

7系铝合金是一种可热处理强化的铝合金,通过改变热处理工艺的方法可以提高铝合金的抗应力腐蚀性能.本文研究了不同升温时效处理下,铝合金在含硫酸盐还原菌(SRB)模拟海洋溶液中的应力腐蚀行为,并通过应力-应变曲线和断口形貌,对比分析了铝合金在无菌溶液和SRB溶液中的应力腐蚀行为差异.研究表明,升温时效处理可以提高合金的自腐蚀电位,降低腐蚀电流密度和合金的应力腐蚀敏感性.硫酸盐还原菌(SRB)通过代谢促进了合金的腐蚀,改变了合金应力腐蚀开裂的机理,使合金的应力腐蚀开裂主要机理由阳极溶解转变为氢致开裂.

Stress corrosion behavior of 7075 aluminum alloy by heating aging treatment in simulated seawater containing SRB

The 7-series aluminum alloy is a kind of alloy which can be strengthened by heat treatment. Therefore, the heat treatment process is an important factor affecting the stress corrosion performance. In this paper, a new kind of thermal treatment draft was researched for tuning the comprehensive properties of Al alloy. The effect of SRB on stress corrosion behavior of aluminum alloy under different heating aging treatment was studied in simulated marine solution with sulfate-bearing reducing bacteria (SRB). The difference of stress corrosion behavior of aluminum alloy in sterile solution and SRB solution was compared by analyzing the stress-strain curves and fracture morphology. The results show that the heating aging treatment could improve the self-corrosion potential of the alloy, reduce the corrosion current density and stress corrosion sensitivity (I_scc) of the alloy. SRB could promote the corrosion of the alloy through metabolism and change the mechanism of stress corrosion cracking, which made the main mechanism of the alloy change from anodic dissolution to hydrogen induced cracking.