The Localized Corrosion and Stress Corrosion Cracking of a 6005A-T6 Extrusion Profile

Materials

Jijun Ma¹  Jun Gao¹  Quanmei Guan¹  Jing Sun¹  Haisheng Wang¹  Qingwei Yang²  Bin Tang²  Jian Tang²  Hongchao Kou²  Jun Wang²  Jinshan Li²  William Yi Wang²  Chengxiong Zou² 

[1] CRRC Tangshan Co., Ltd., Tangshan 063035, China;State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an 710072, China;

关键词: stress corrosion cracking;    pitting;    intergranular corrosion;    grain boundaries;   

DOI  :  10.3390/ma14174924

来源: DOAJ

【 摘 要 】

In the present work, the localized corrosion and stress corrosion cracking (SCC) behaviors of a commercial 6005A-T6 aluminum extrusion profile was studied comprehensively. The velocity of crack growth in self-stressed double-cantilever beam (DCB) specimens under constant displacement was estimated, which also provides insight into the local microstructure evolutions at the crack tips caused by the localized pitting corrosion, intergranular corrosion (IGC), and intergranular SCC. Characterizations of local corrosion along the cracking path for a period of exposure to 3.5% NaCl were revealed via optical microscope (OM), scanning electron microscope (SEM), and electron backscatter diffraction (EBSD). The typical features of the pits dominated by the distribution of precipitates included the peripheral dissolution of the Al matrix, channeling corrosion, intergranular attack, and large pits in the grains. The discontinuous cracking at the crack tips indicated the hydrogen-embrittlement-mediated mechanism. Moreover, the local regions enriched with Mg₂Si and Mg₅Si₆ phases and with low-angle grain boundaries presented better SCC resistance than those of the matrix with high-angle grain boundaries, supporting a strategy to develop advanced Al–Mg–Si alloys via interfacial engineering.

【 授权许可】

Unknown