The objective of this study is to develop a surface modification technology for submillimeter-thick metal sheets using Laser Induced Particle Impact Test (LIPIT) and to evaluate the mechanical and fatigue properties after treatment. LIPIT is a testing method that utilizes the rapid volume expansion of materials caused by laser ablation to eject microparticles at ultra-high speeds. To enable processing over a wide area, we developed a continuous ejection type LIPIT capable of continuously ejecting particles. This device incorporates a conveyor-type target transport mechanism and a synchronization control mechanism controlled by a custom-made control program, enabling stable continuous irradiation. Next, test specimens treated with LIPIT were prepared using this device, and tensile tests, tensile fatigue tests, and bending fatigue tests were conducted in comparison with untreated test specimens. These tests confirmed that LIPIT treatment has the effect of improving mechanical properties and fatigue properties. Particularly, the results of the fatigue tests suggested that LIPIT treatment suppresses surface plastic deformation, thereby extending fatigue life, enabling an examination of the mechanism behind the improvement in fatigue strength. In summary, this study achieved the development of a surface modification method for metal sheets using LIPIT and demonstrated its effectiveness.
Amamiya et al. (Wed,) studied this question.