OS0729 ECAPにより結晶粒を微細化した銅の微小き裂進展挙動(構造用材料の疲労挙動と寿命評価,オーガナイズドセッション)

概要

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High-cycle fatigue tests were carried out on smooth specimens of ultrafine-grained copper produced by equal channel angular pressing(ECAP). Grain sizes of 300nm were formed after twelve passages of ECAP pressing by Be route. Fatigue tests were conducted using a rotating bending fatigue machine. A major crack, which led to the final fracture of the specimen, initiated from shear bands. After initiation, Hie growth rate increased with an increase in crack length. However, a decrease in growth rate with a change in growth path morphology occurred when the crack length 0.1<l<0.3 mm. The fracture surface showed a planar, granular, and striated surface in the range of l<0.1 mm, 0.1<l<0.3mm and l>0.3mm, respectively. This decrease occurred because of a change in the crack growth mechanism and is explained by considering the interrelation between grain size and the reversible plastic zone size at the crack tip.
一般社団法人日本機械学会の論文
2009-07-24