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用WOL缺口压缩试样研究LC4铝合金在3.5％NaCl水溶液中的压应力腐蚀.有限元计算指出,试样加压缩位移时缺口附近有压应力集中.实验结果表明,当压缩位移大于临界值后产生压应力腐蚀裂纹. 实验测出压应力腐蚀裂纹的门槛值为K_(ISCC*)=27.6MPam~(1/2),等于拉应力腐蚀门槛值的3.5倍.在相同K_I下压应力腐蚀裂纹的孕育期比拉应力高一个数量级.压应力腐蚀时获得带有平行条纹花样的准解理断口,这和拉应力腐蚀的沿晶断口完全不同。
The compressive stress corrosion of LC4 aluminum alloy in 3.5% NaCl aqueous solution was studied by using WOL notched compressive specimens. Finite element calculations show that compressive stress concentrates near the notches when the specimen is compressed and displaced. The experimental results show that when the compressive displacement is larger than the critical value The stress threshold value of the stress corrosion crack is K_ (ISCC *) = 27.6MPam ~ (1/2), which is equal to 3.5 times of the threshold value of the tensile stress corrosion stress.At the same K_I stress corrosion cracking Of the incubation period is an order of magnitude higher than the tensile stress.When compressive-stress corrosion, the quasi-cleavage fracture with parallel stripe pattern is obtained, which is completely different from the intergranular fracture with tensile stress corrosion.