Raman Stress Evaluation: Hydrostatic vs. Biaxial Calibration
L M. Braun, Grady S. White
Comparisons of two technical approaches for stress measurement based on the peak shifts associated with micro-Raman spectra are described. Stress values were obtained from evaluation of the relationship between peak shift and stress determined by both a single line hydrostatic calibration and by evaluation of the phonon deformation protential terms. Single crystal sapphire and polycrystalline alumina were used to compare the hydrostatic and phonon deformation potential calibration approaches. In this paper, we discuss the advantages of the phonon deformation potential approach as compared with the single line hydrostatic approach. We demonstrate that it is possible to evaluate stress for biaxial and hydrostatic stress states for single cyrstals. We also present data and analysis on an individual grain within a large grain polycrystalline material.