Abstract by Scott Smith
Chemistry and Biochemistry
Nondestructive Testing with Second Harmonic Generation
Non-destructive testing (NDT) seeks to prevents the catastrophic failure of a component without further compromising it, allowing for its continued use. Current NDT methods probe for microscopic cracks which are the precursors to catastrophic failure, and indicate extensive fatigue. These methods are of limited sensitivity because they cannot detect the small-scale plastic deformations (PD) the breaks. PDs are caused by an accumulation of internal irregularities in a material’s lattice, known as dislocations. An abundance of these dislocations causes an increase in the number of intrusions and extrusions on the surface of the material and may be detected by Second Harmonic Generation (SHG) Spectroscopy. Our research has shown SHG to be both fast and unprecedented in its sensitivity to PD in many commercial materials, such as 2024 Al. Our aim is to use SHG signal to extrapolate the extent which a 2024 sample has been stressed, proving SHG to be a viable method of NDT.