EBSP法によるSCCき裂先端の塑性変形挙動解析

Analysis of plastic deformation behavior at SCC crack tip by EBSP method

加治 芳行  ; 三輪 幸夫; 塚田 隆 

Kaji, Yoshiyuki; Miwa, Yukio; Tsukada, Takashi

EBSP法によるSCCき裂先端の塑性変形挙動解析を実施した結果、以下のような結論を得た。(1)SCCき裂先端の塑性変形挙動を定量的に評価するための基礎データとして、SUS316L鋼を用いた高温水中SSRT試験片を用いて、塑性変形量と結晶粒のmisorientation量との関係を取得し、この関係を用いて局所的な塑性ひずみを推定することを可能にした。(2)misorientation量と塑性変形量との関係を用いて、SCCき裂及び延性き裂先端の塑性ひずみを測定した結果、延性き裂先端近傍の塑性ひずみはSCCき裂に比べて大きいことがわかった。しかし、塑性変形領域はいずれのき裂においても、き裂先端の結晶粒1個程度の領域であった。

From results of analysis of plastic deformation behavior at SCC crack tip by EBSP method, the conclusions was obtained as follows: (1)Regarding to basic data for quantitative evaluation of plastic deformation behavior at SCC crack tip, we obtained relationship between plastic deformation and misorientation of grain using SSRT result for SUS316L stainless steel in high temperature water and local plastic strain was able to estimate using this relationship. (2)From experimental results of plastic strain at SCC crack and ductile crack tips using relationship between misorientation and plastic deformation, plastic strain near ductile crack tip was larger than that at SCC crack tip. Plastic deformation region was, however, corresponded to region of about one grain at crack tip for both SCC and ductile cracks.