| Abstract |
| Delayed hydride crack (DHC) tests were conducted on Zr-2.5Nb tubes with different distributions of the β-Zr at temperatures ranging from 125 to 300℃ to determine temperature dependences of their DHC velocity (DHCV) and striation spacing. The Zr-2.5Nb tube with a semi-continuous β-Zr and a higher yield strength had a higher activation energy for the DHCV and for the striation spacing, corresponding to 48.9 kJ/mol and 12.4 kJ/mol, respectively, compared to the Zr-2.5Nb tube with a fully discontinuous β-Zr and a lower yield strength. It is found that the activation energy for the DHCV is the sum of the activation energy for hydrogen diffusion and the striation spacing representing the hydrogen concentration gradient at the crack tip. This study provides supportive evidence to the feasibility of Kim`s DHC model. |
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| Key Words |
| Zr-2.5Nb, delayed hydride crack velocity, activation energy, hydrogen diffusion, striation spacing |
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