Abstract by Emma Carlsen
Chemistry and Biochemistry
Spectroscopic Analysis of Chemically Stressed Naval Grade Aluminum
Due to their light-weight, high strength, and corrosion-resistant properties, 5xxx series aluminum alloys are used in the construction of many US Navy ships. Sensitization, the formation of Mg2Al3 precipitates (β phase) along the grain boundaries of the naval grade aluminum, is found to increase susceptibility to extreme corrosion. β phase build up can occur over prolonged periods of time and upon exposure to temperatures above 65°C. Sensitization is reversible upon exposure to a recently developed heat treatment, but there is not a practical infield method for detection. Preliminary results, using a spectroscopic method called Second Harmonic Generation (SHG), have indicated SHG could serve as a viable detection system. SHG, due to its ease of mobility, minimal sample preparation, and nondestructive nature would be an ideal detection method. Application of this research will help in the detection of aluminum sensitization of Naval ships, allowing the reversal process to be properly employed to prevent further degradation. In addition, this research will significantly advance nondestructive evaluation methodology.