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2841522 
Journal Article 
REVERSING SENSITIZATION OF NATURALLY EXFOLIATED 5456-H116 ALUMINUM ALLOYS 
Chen, RenYu; Lai, CC 
2014 
Yes 
Journal of Marine Science and Technology
ISSN: 1023-2796 
22 
4 
450-454 
WOS:000345549700006 
5456-H116 Al-Mg alloy has been broadly used in the U.S. Navy in order to meet the demand of reducing ship hull weight while considering high specific strength, corrosion resistance, and weldability. A particular concern of these alloy is sensitization, which causes it to be sensitized when highly anodic beta Phase (Al3Mg2) is precipitated at grain boundaries especially in service exceeding 65 similar to 200 degrees C, leading to intergranular corrosion (IGC), exfoliation and stress corrosion cracking (S CC). This study investigated the reversal of sensitization of a naturally exfoliated 5456-H116 alloy plate by planned heating treatment with a short exposure to 250 degrees C. The properties of sensitized specimens of 5456-H116 were investigated using microhardness testing, electrochemical measurements, Nitric Acid Mass Loss Testing (NAMLT), optical microscopy, and Scanning Electron Microscopy (SEM). The results reveal that the corrosion resistance of the stabilized specimens approached those of the unsensitized plates, and their mechanical strength was not adversely affected during the recovery process. Therefore, in-service plates can be refurbished by stabilizing heat treatment rather than replacement, potentially reducing maintenance costs. 
sensitization; beta phase; corrosion; Al3Mg2; 5456-H116