著者

桑水流 理 寺西 正輝 小林 正和 戸田 裕之

出版者

公益財団法人 高輝度光科学研究センター

雑誌

SPring-8/SACLA利用研究成果集 (ISSN:21876886)

巻号頁・発行日

vol.9, no.6, pp.383-390, 2021-11-29 (Released:2021-10-29)

参考文献数

16

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板状の介在物粒子を含むアルミニウム鋳造合金の疲労破壊挙動を放射光 CT および大規模有限要素解析により検証した。疲労亀裂は主として介在物と母相の界面剥離から生じた。界面剥離と介在物粒子の破損はほぼ同時に多数発生し、多数の空隙を生じさせた。単一の亀裂の進展速度は遅く、多数の空隙が合体することで、亀裂は進展した。材料表面では Al 母相の塑性ひずみが蓄積し易く、Al 母相のひずみ硬化による応力増加が、材料表面近傍での介在物の破損を生じさせた。

著者

寺西 正輝 桑水流 理 小林 正和 戸田 裕之

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.84, no.863, pp.18-00028, 2018 (Released:2018-07-25)

参考文献数

23

被引用文献数

1

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Fatigue crack in cast aluminum alloys subject to low-cycle fatigue is initiated mainly by the fracture of Si particles. To investigate the mechanism of Si particle fracture, we carried out the geometrical measurements and finite element analysis for a lot of Si particles in their actual geometrical configuration. The synchrotron X-ray CT was used for the geometrical measurement and the image-based finite element modeling. The fracture of Si particles were detected as a source of crack initiation from the CT images captured during the fatigue test. The large-scale voxel finite element model contains the outer surface, pores, Si and intermetallics. The number of elements was about 150 million. Two cycles of loading were calculated. The finite element analysis and its post-processing were performed on the supercomputers by the massively-parallel computing. The result of finite element analysis showed that the first principal stress was concentrated around the aligned or gathered Si particles, and the gradual increase by cyclic loading in the stress of the Si particles appeared near the outer surface and pores. Moreover, the result of geometrical measurements showed that the volume, shape index and adjacency index of each Si particle could be used to evaluate the likelihood of particle fracture. The probability of particle fracture was statistically evaluated with respect to those geometrical and mechanical parameters. The relationship between mechanical and geometrical parameters were also examined. As the result, the criteria of fractured Si particle was proposed by using the combination of geometrical and mechanical parameters.