Al−Cu−Li合金AA2195在低应变速率和3.5NaCl溶液中的抗裂性能

摘要

研究Al?Cu?Li合金AA2195在3.5%NaCl环境中的耐蚀和抗裂性能,并将其与另一高强合金AA2219进行比较.采用浸泡腐蚀和恒电位极化实验测定合金的总耐蚀性能;采用低应变速率测试法确定合金的应力腐蚀开裂(SCC)性能.利用SEM?EDS和光学测量技术对合金样品进行表征以研究其腐蚀形貌、元素含量和腐蚀深度的变化.用韧性的减少量作为估算合金应力腐蚀开裂(SCC)敏感性的一个参数.结果表明,由于较低的腐蚀速率、较小的腐蚀深度和宽度,AA2195合金比AA2219合金具有更好的耐蚀性能.然而,两种合金的SCC参数(εNaCl/εair)均大于0.90,说明此两种合金均具有较好的抗裂性能.断裂样品的SEM?EDS结果表明,两种合金均为典型的脆性断裂形貌.%The general corrosion and environmental cracking resistances of Al?Cu?Li alloy AA2195 were investigated in 3.5% NaCl environment and compared with those of another high strength alloy AA2219. The general corrosion resistance of these alloys was examined using immersion corrosion and potentiodynamic polarization tests, while the stress corrosion cracking (SCC) resistance was evaluated by slow strain rate test (SSRT) method. The tested samples were further characterized by SEM?EDS and optical profilometry to study the change in corrosion morphology, elemental content and depth of corrosion attack. The reduction in ductility was used as a parameter to evaluate the SCC susceptibility of the alloys. The results indicated that the corrosion resistance of AA2195 alloy was better than that of AA2219 alloy as it exhibited lower corrosion rate, along with lower pit depth and density. However, the SCC index (εNaCl/εair) measured was greater than 0.90, indicating good environmental cracking resistance of both the alloys. Detailed fractography of the failed samples under SEM?EDS, in general, revealed a typical ductile cracking morphology for both the alloys.