An Analysis of Variability in Sensitization Behavior of 5083-H131 and the Impacts on Yield Strength

Author(s):

Heather Murdoch, Daniel Magagnosc, Lindsey Blohm, Denise Yin, and Tim Walter

Abstract:

Multiple plates of 5083-H131, representing a variety of suppliers and plate thickness, were assessed for their susceptibility to sensitization. More variability in the degree of sensitization was observed at the lower sensitization temperature (70°C). The H131 behavior was also compared to an example 5083-H116 plate that was known to be highly susceptible to sensitization. All sensitized plates and conditions exhibited a decrease in the yield strength. Microstructural characterization was performed on one plate in conjunction with a detailed examination of strengthening model parameters to establish the specific mechanisms contributing to the yield drop. The yield drop in sensitized 5083 is caused by Mg leaving solid solution to form the β phase and dislocation recovery. The proportional effect of these two mechanisms will vary depending on plate (e.g., its initial dislocation density, grain boundary density and character, initial precipitate density, and overall Mg content) but it is generally expected to be influenced more by the dislocation recovery.