SUS304鋼における下限界近傍の真空中高温疲労き裂伝ぱ挙動(<特集>破壊力学)

概要

論文の詳細を見る
Fatigue crack growth tests were conducted for SUS304 stainless steel in the near-threshold region using singleedge-cracked (SEC) specimens at 350℃, 550℃ and 650=C in a vacuum. Crack growth behaviors of SUS304 in a vacuum were compared with those in air to investigate the effect of the environment and oxidation on the behavior of fatigue crack growth in the near-threshold region. It was found that threshold value, ΔK_<th>, was higher than that in air, and that ΔK_<th>, at high temperatures reached a maximum value at about 550℃. When the value of K_<max> was increasedin a threshold condition obtained by using the conventional ΔK-decreasing test, crack growth was observed for ΔK lower than the conventional threshold. Crack growth was also observed after successive increase in K_<max> in the newly established subthreshold region in a vacuum as well as in air. In the region below a certain value of AA", however, crack no longer grew even after the change of K_<max> at 550℃. Discussion was made on the characteristics of the fatigue crack growth threshold.
社団法人日本材料学会の論文
2004-08-15