Abstract by Spencer Jeppson
Chemistry and Biochemistry
Detection of Aluminum Sensitization with Second Harmonic Generation
Second harmonic generation (SHG) signal response is sensitive to changes on the surface of a material. We employ this phenomenon to probe 5xxx series naval-grade aluminum for sensitization that results from the migration of Mg to the crystal grain boundaries, forming beta phase aluminum. Beta phase aluminum is sensitive to corrosion, resulting in damage to the ships. Although this sensitization can be reversed, no reliable, nondestructive method currently exists to determine if beta phase has formed. We have measured an increase in SHG signal on aluminum samples known to be sensitized, making this a promising method for sensitization detection. Using precision-machined samples, we plan to control the sensitization of aluminum and establish a link between degree of sensitization and the observed SHG signal.