Abstract
One way to increase gas mileage 50% by 2050, a goal of the U.S. government, is to reduce the weight of the vehicle, using lightweight alloys such as magnesium. AZXX Mg alloys have been investigated for this purpose, but are still highly susceptible to stress corrosion cracking. The presence of pits and hydrogen embrittled sections concentrate the stress, leading to cracking and failure. In order to determine the interaction between tensile properties and corrosion behavior, two saltwater environments were used to examine the effects of chloride ion exposure on the corrosion of an extruded AZ61 alloy held under constant strain (approximately 80% of tensile yield strength) over 60 hours. The effects of constant strain on the surface corrosive behavior and the tensile strength were determined at various intervals. The stress-strain relationship minimally decreased over time for the salt spray environment, while large changes were seen in the stress-strain relationship for the immersion environment. In addition, there was a minimal decrease in stress over 60 hours of the AZ61 alloy in the salt spray environment but a 20% decrease in stress over 60 hours in the immersion environment. The differences between stress-strain relationships were attributed to a decrease in surface area of the samples due to the continuous presence of water for the immersion environment, which resulted in a decrease in the ability to withstand applied stress. The formation of pits due to chloride ions for both environments concentrated the applied stress, leading to a decrease in the elongation to failure for both environments.
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Martin, H.J. et al. (2014). Corrosion-Stress Relaxation Effects on Tensile Properties of an AZ61 Magnesium Alloy. In: Alderman, M., Manuel, M.V., Hort, N., Neelameggham, N.R. (eds) Magnesium Technology 2014. Springer, Cham. https://doi.org/10.1007/978-3-319-48231-6_67
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DOI: https://doi.org/10.1007/978-3-319-48231-6_67
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