Zr微量添加高合金における高温疲労き裂進展抑止機能

概要

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Arrest function in fatigue crack growth at 25 and 550℃ in air was investigated for a alloy with zirconium in 0.17 Wt%, Fe-27Cr-35Ni-0.17Zr, and a alloy without zirconium, Fe-21Cr-32Ni. The main conclusions obtained are as follows. (1) The fatigue threshold under closure-free condition was about 40% higher for Fe-27Cr-35Ni-0.17Zr alloy than for Fe-21Cr-32Ni alloy at 550℃, while the threshold was independent of the alloys at 25℃. (2) The fatigue limit at 550℃ was about 40% higher for Fe-27Cr-35Ni-0.17Zr alloy than for Fe-21Cr-32Ni alloy. (3) The improvement in high-temperature fatigue threshold were explained, considering that the presence of zirconium strengthened the oxide film at the crack tip. Accordingly, we concluded that a small addition of Zr could gives rise to an arrest function of fatigue crack growth at elevated temperatures.
1999-04-25