Visualizing Shock Induced Thermo-Mechanical Change at Bi-Crystal Interface Using Laser Array Based Nano-Second Raman Spectral Imaging

Under shock compression, Raman spectroscopy (RS) requires signal acquisition in pico- to nano-second time frames. Therefore, analysis under shock compression using RS requires simultaneous deconvolution of Raman spectra over the sample domain and reconstruction of the Raman spectral image after acquiring the spectra. In this study, a Raman spectral imaging technique using a laser array on the sample surface was developed and used to construct a 2D spectral image using an assembly of mirrors. The developed system was used to study shock wave propagation in a mock energetic material where it is important to obtain the microscale resolved distribution of stress and temperature as the shock wave creates a highly inhomogeneous wave structure due to the mismatch in impedances of different phases and interfaces. The Raman spectral image was captured during the propagation of shock waves through the interface of sucrose crystals. To predict the role of the interface in energy dissipation, an analysis of shock energy dissipation during shock propagation between material interfaces was done, and comparisons between ideal interface calculations and measured experimental results are reported.