Surface Treatment of Aluminium 6061-T6 Using Multi-shot Laser Plasma Shock Processing (LPSP) Without Confinement
In the present work a metal surface was treated in open air with a laser beam at without confinement of the plasma. A convergence lens was used to focus the laser beam from a Q-switched frequency doubled Nd:YAG laser emitting at 532 nm wavelength, 230 mJ with 8 ns full width at half maximum (FWHM) pulse duration, 10 Hz repetition rate and a spot diameter of 0.8 mm. The treatment was carried out for peening Al 6061-T6 by using laser plasma shock processing (LPSP). The result from X-ray diffraction (XRD) analysis of the Al 6061-T6 was -942.97 MPa of compressive residual stress into the surface with a pulse density 203.728 pulses/cm2. The surface roughness had been detected because of the pulse density was very high, a comparative detection done between the unpeened and the peened Al 6061-T6 for checking the damage that can be caused on the surface from increasing the pulse density.
Keywords: Nd:YAG laser, Al 6061-T6, laser peening, laser plasma shock processing (LPSP), laser plasma, residual stress, shock waves