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Journal Articles

Evaluation of internal strain distribution of dissimilar laser welding using high energy X-rays

Shobu, Takahisa; Shiro, Ayumi*; Muramatsu, Toshiharu*

SPring-8/SACLA Riyo Kenkyu Seikashu (Internet), 9(5), p.318 - 323, 2021/08

https://doi.org/10.18957/rr.9.5.318

Laser welding has already been put into practical use for various metal materials because the irradiation area is very small and the control is easy. In this study, we evaluated strain, stress, deformation, etc. near the processing affected area by high-energy synchrotron radiation X-ray diffraction method, which is one of the problems of laser welding of different materials that are expected to be put into practical use. As a result of internal deformation measurement of the bonding of dissimilar materials of copper and iron, it was confirmed that the copper side with a high coefficient of linear expansion was hardly deformed, strong tensile strain on the iron side, and a plastic deformation region on the heat-affected zone. In addition, a retained austenite phase, which is thought to be caused by the mixture of copper, was observed in the plastic deformation region of iron, and further problems were clarified in the evaluation of material strength in the mixed metallic materials.

Journal Articles

Improving fatigue performance of laser-welded 2024-T3 aluminum alloy using dry laser peening

Sano, Tomokazu*; Eimura, Takayuki*; Hirose, Akio*; Kawahito, Yosuke*; Katayama, Seiji*; Arakawa, Kazuto*; Masaki, Kiyotaka*; Shiro, Ayumi*; Shobu, Takahisa; Sano, Yuji*

Metals, 9(11), p.1192_1 - 1192_13, 2019/11

AA2019-0690.pdf:3.91MB

https://doi.org/10.3390/met9111192

Times Cited Count：15 Percentile：64.79(Materials Science, Multidisciplinary)

The purpose of the present study was to verify the effectiveness of dry laser peening (DryLP), which is the peening technique without a sacrificial overlay under atmospheric conditions using femtosecond laser pulses on the mechanical properties such as hardness, residual stress, and fatigue performance. After DryLP treatment of the laser-welded 2024 aluminum alloy, the softened weld metal recovered to the original hardness of base metal, while residual tensile stress in the weld metal and heat-affected zone changed to compressive stresses. The fatigue life almost doubled at a stress amplitude of 180 MPa and increased by a factor of more than 50 at 120 MPa. As a result, DryLP was found to be more effective for improving the fatigue performance of laser-welded aluminum specimens with welding defects at lower stress amplitudes.

Journal Articles

Mechanical properties of weldments using irradiated stainless steel welded by the laser method for ITER blanket replacement

Yamada, Hirokazu*; Kawamura, Hiroshi; Nagao, Yoshiharu; Takada, Fumiki; Kono, Wataru*

Journal of Nuclear Materials, 355(1-3), p.119 - 123, 2006/09

https://doi.org/10.1016/j.jnucmat.2006.04.010

Times Cited Count：5 Percentile：36.24(Materials Science, Multidisciplinary)

In this study, the bending properties of welding joint of irradiated material and un-irradiated material (irradiated/un-irradiated joints) were investigated using SS316LN-IG, which is the candidate material for the cooling pipe of ITER. The results of this study showed that the bending position of joints using un-irradiated material was un-irradiated part and that the bending position of irradiated/irradiated joints was fusion area or HAZ (heat affected zone). Although the bending position of joints was different bor the combination pattern between irradiated and un-irradiated materials, the bending strength of joint was almost same. Additionally, it is confirmed that bending strength did not depend on the combination pattern between the irradiated and un-irradiated materials, nor on the relationship between the heat input direction and the bending load direction.

Journal Articles