著者

張 学超 森 敬祐 真壁 朝敏 安藤 新二 井上 晋一

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会九州支部講演論文集

巻号頁・発行日

vol.2021, 2021

著者

張 学超 森 敬祐 真壁 朝敏 井上 晋一 安藤 新二

出版者

公益社団法人 日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.70, no.6, pp.473-478, 2021

被引用文献数

1

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<p>Push-pull fatigue tests of rolled magnesium alloys AZ31 and AZX912 were performed with a side-notch plate specimen to examine the effect of a single overload on the crack growth behavior under a stress ratio of -1. The behavior in retardation of crack growth was unclear in the case of AZ31 because the crack growth rate was relatively higher at the overload point. However, this was observed clearly, when the branching of the crack tip happened in the case of AZX912. The geometry of the fracture surface and the changes in crack growth path were related to the crack growth behavior. The crack opening level became higher when the crack growth rate was lower. Therefore, the crack closure is related to the retardation of the crack growth rate. When the branching of a crack tip occurred, not only the residual compression stress at crack front but also the variation of local crack growth direction after overload affected the fatigue crack growth behavior. </p>

著者

森 敬祐 真壁 朝敏 安藤 新二 井上 晋一

出版者

一般社団法人 日本高圧力技術協会

雑誌

圧力技術 (ISSN:03870154)

巻号頁・発行日

vol.58, no.1, pp.14-21, 2020

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Fatigue crack growth tests of rolled magnesium alloy AZ31 were performed with a side-notch plate specimen under negative mean stress conditions. In the results of the present study, even if the experimental conditions were the same, the crack growth behavior varied depending on the condition of the specimen and depending on the microstructure. The local friction between large size and small size crystals and the shear deformation are expected to be related to the crack closure. The crack growth rate was affected by the crack opening stress. When the crack growth rate was lower level, the crack closure behavior worked due to the plastic deformation and the roughness of the fracture surface. There was local rough pattern which work as the shear lip at sides of the crack surface.