Fiber-delivered Laser Peening System To Improve Mechanical Properties Of Metal Surface.
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M. Yoda, N. Mukai, Y. Sano, K. Ogawa, M. Kimura, K. Sato, T. Uehara, A. Sudo & N. Suezono.
Fiber-delivered laser peening system to improve mechanical properties of metal surface M. Yoda, N. Mukai, Y. Sano, K.Ogawa, M. Kimura, K. Sato, T. Uehara, A. Sudo and N. Suezono Power Systems and Services Company, Toshiba Corporation, Japan Abstract Laser peening is defined as a novel process to improve residual stress on material surface by irradiating focused high-power laser pulses in water. We have been developing a system to apply laser peening to in-core components of nuclear reactors as a preventive maintenance measure against stress corrosion cracking (SCC). In many applications of this system, it would be desirable to deliver high-power laser pulses through flexible optical fibers to improve its accessibility for narrow spaces. However, the high intensity of laser pulses causes damage on the entrance surface and inside the core material of the optical fiber. In order to mitigate the phenomena, we introduced a beam homogenizer, which averages the spatial distribution of laser p