Study on Residual Stress of 3A21 Metal Sheet by Laser Shock in Oblique Angle

3A21 metal sheet was shocked by Nd-glass laser in oblique angle under the function of pulse energy 42 J, pulse width 23 ns, pulse power 1.2×109 W, the angle between input beam and normal of sample is 30°. The center of the deformation of the sheet is 3 mm away from the geometric center. Residual stresses of crossing center side in length direction and the distribution of space in the positive and negative sides are measured by XRD, which are compressive stress 100 MPa. The diagonal length of the sheet is longer than the one of the crossing center side in length direction, the force that needs to form in the diagonal direction is bigger, so compressive stress is much bigger. The capstone of the square sheet is squeezed, the procession seriously increase, so compressive stress is the biggest one.