Abstract
In a conventional laser peening (C-LP) without a protective coating, a treated metallic surface is always melted after the C-LP processing, resulting in the generation of tensile residual stress. In order to establish a new LP technique without surface melting, we have investigated the effect of an LP (Ink-LP) using a black liquid ink (an indian ink) as an absorber. The laser wavelength and pulse duration of the laser used were 532 nm and ∼5 ns, respectively. We changed the pulse energy and spot diameter of the laser beam, resulting in the corresponding power density of ∼1 - 15 GW/cm2. The pulse number was 1. The metal sample used was an aluminum alloy (A2017). As a reference, we have conducted similar experiments for the C-LP processing, which in the metallic surface are directly irradiated, and have compared surface deformation and surface melting between the Ink-LP and C-LP processing. As a result, it was found that the Ink-LP processing can provide us with a promising LP effect with a wider treatment area and no surface melting in comparison with those of the C-LP processing. Thus, we have showed the usefulness of the Ink-LP processing using a black ink.
