The Effect of Mg Content on Intergranular Corrosion of Al-Mg-Mn Alloys after Annealing

Abstract:

The Intergranular Corrosion (IGC) properties of Al-xMg-0.6Mn (x=3, 4, 5, 6 and 7) wt.% alloys were studied using the mass loss test. The mass loss test results of the alloys annealed at 100-300 ̊C for 1h indicated that the alloys with 3 and 4% Mg were resistant to IGC. While the mass loss values of the 6 and 7% Mg alloys were increased to IGC severe sensitive region, and then abruptly fallen to the IGC-resistant region with the increasing temperature. The mass loss-temperature curve of 5% Mg alloy was actually located between them. After isothermal annealing, the mass loss results indicated a stabilization temperature of the alloys with 5, 6 and 7% Mg appeared at the temperature beyond 220 ̊C, 250 ̊C and 270 ̊C, respectively. Furthermore, below the stabilization temperature 10-20 ̊C, it was observed a type of “special mass loss curve ” in so-called transition region that was showed a quick mass loss increasing to sensitization region and then a decrease to the IGC resistant region with a prolonged annealing time. To explore the “special curve” in transition region, the TEM observation of Al-7Mg alloy annealing at 250 ̊C was conducted, which indicated the sensitization resulted from the continuity of β phase, while the descending to the IGC might to be attributed to the spheroidization of β phase.

• Periodical: Materials Science Forum (Volume 877)
• Pages: 514-521
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.877.514
• Online since: November 2016
• Authors: Yu Sheng Ding, Kun Yuan Gao*, Chang-Jian Lin, Sheng Ping Wen, Hui Huang, Xiao Lan Wu, Zuo-Ren Nie, De Jing Zhou
• Keywords: Al-Mg Alloy, Intergranular Corrosion, Mg Content, Stabilization

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