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

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.

Technical issues of welding of reduced activation ferritic/martensitic steels at the fabrication of ITER test blanket module

Tanigawa, Hiroyasu; Ogiwara, Hiroyuki; Hirose, Takanori; Shiba, Kiyoyuki; Serizawa, Hisashi*; Kawahito, Yosuke*; Tanaka, Manabu*; Katayama, Seiji*; Mori, Hiroaki*; Nishimoto, Kazutoshi*

no journal, , 

Reduced activation ferritic/martensitic steels (RAFMs) are recognized as the primary candidate structural materials for fusion blanket systems. These steels have been developed based on substantial industrial experience with high chromium heat resistant ferritic/martensitic steels (such as modified 9Cr-1Mo), but with Mo and Nb replaced by W and Ta, respectively. The objective of this paper is to review the R&D status of F82H and to identify the key technical issues for the fabrication of an ITER Test Blanket Module (TBM) suggested by recent achievements in Japan.