COMPARATIVE STUDY OF SYMMETRIC AND ASYMMETRIC DEFORMATION OF AL SINGLE CRYSTAL UNDER MICROSCALE LASER SHOCK PEENING

The process of laser shock peening induces compressive residual stresses in a material to improve material fatigue life. For micron sized laser beams, the size of the laser-target interaction zone is of the same order of magnitude as the target material grains and, thus, the target material must be considered anisotropic and inhomogeneous. Single crystals are chosen to study the effects of the anisotropic mechanical properties. It is of further interest to investigate the response of symmetric and asymmetric slip systems with respect to the shocked surface. In the present study, analytic, numerical, and experimental aspects of laser shock peening on two different crystal surfaces, (110) and (1 (1) over bar4) of aluminum single crystals are studied. Anisotropic slip line theory is employed for the construction of slip line fields for both orientations and compared with numerical results. Lattice rotations of the cross section are measured using Electron Backscatter Diffraction (EBSD).