Desensitization of AA5083 alloy via pulsed laser irradiation and its microstructural mechanism.

In the present work, a laser surface desensitization (LSD) method was carried out on sensitized AA5083 alloy with the underlying microstructural evolution examined. The enhanced corrosion resistance after LSD process was confirmed by nitric acid mass loss test (NAMLT), immersion test and electrochemical measurements, which is mainly ascribed to the modification of grain boundary chemistry. Accompanied with the dissolution of grain boundary β (Al 3 Mg 2) phase during LSD process, the grain boundaries could be characterized by Mg segregation or nano-sized Mg-rich clusters, which may also be absent from chemical uniformity depending on grain boundary misorientation. [Display omitted] • LSD successfully achieves a local reversing sensitization of AA5083 alloy. • LSD results in the dissolution of grain boundary β phase. • Grain boundary chemistry after LSD varies depending on grain boundary misorientation and laser power. [ABSTRACT FROM AUTHOR]