时效制度对1441Al-Li合金抗腐蚀性能的影响  

Effect of aging condition on corrosion resisitance property of 1441 Al-Li alloy

作　　者：韩烨[1] 郑子樵[1] 孔祥[1] 林毅[1] 

机构地区：[1]中南大学材料科学与工程学院,长沙410083

出　　处：《粉末冶金材料科学与工程》2014年第4期514-522,共9页Materials Science and Engineering of Powder Metallurgy

摘　　要：对固溶态1441Al-Li合金板材分别进行T6时效,以及5%冷轧预变形后再进行150℃时效,即T8时效处理,通过晶间腐蚀(IGC)、剥落腐蚀(EXCO)实验、极化曲线测试及透射电镜(TEM)分析,研究时效制度对1441铝锂合金的室温抗晶间腐蚀性能、抗剥落腐蚀性能及微观组织的影响。结果表明,合金经T6或T8时效处理后,随时效时间延长,合金微观组织由欠时效的晶内析出均匀的δ′相,变为晶内析出δ′相和S′相,以及沿晶界析出平衡相δ相和S相,因此合金抗腐蚀性能顺序为欠时效>峰时效>过时效。与T6时效态相比,经T8时效处理后,晶内析出的δ′相和S′相的数量增加、尺寸减小、分布均匀;同时,沿晶界析出的δ相和S相数量减少,PFZ变窄,合金的抗晶间腐蚀和抗剥落腐蚀能力提高。在3.5%NaCl溶液中进行的极化曲线测试表现出相同的结果。1441Al-Li alloy solid solution was aged at 150 ℃（T8） after T6 aging and 5% cold rolling pre-transformation. The effect of aging condition on intergranular corrosion resistance, exfoliation corrosion resistance and microstructure of 1441 aluminum alloy was investigated by means of intergranular corrosion experiments, exfoliation corrosion experiments, polarization curves measurement and transmission electron microscopy（TEM） analysis. The results show that, with increasing aging time, the uniform precipitation phase of δ′ within the alloy grains in the condition of under aging transforms to the precipitation phases of δ′ and S′ within the grains, as well as δ and S equilibrium phases along the grain boundaries. The order of corrosion resistance is as： under aging〉peak aging〉over aging. Compared with T6 aging, after T8 aging, the volumes of δ′ and S′ phases increase, the size of the phases decreases and distributes uniformly, at the same time the volumes of δ and S phases decrease and PFZ minimizes at grain boundaries, which can increase the susceptibility to intergranular corrosion and exfoliation corrosion. The test of polarization curves in the 3.5% NaCl solution reveals the same conclusion.

关 键 词：1441铝锂合金 晶间腐蚀 剥落腐蚀 微观组织 

分 类 号：TG146.2[一般工业技术—材料科学与工程]