Gaseous hydrogen embrittlement of a hydrided zirconium alloy
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- 作者：J. -H. Huang (1)
M. -S. Yeh (1) - 刊名：Metallurgical and Materials Transactions A
- 出版时间：March 1998
- 出版年：1998
- 期刊代码：31_1543-1940
- 类别：ch
- 卷：29
- 期：3
- 页码：1047-1056
- 数据来源：sp
摘要
ZIRCALOY-4 plate specimens were gaseously hydrided up to 340 ppm H and then tested in a hydrogen gas environment of various pressures up to 2020 kPa a at 25 掳C, 100 掳C, and 200 掳C. Notched tensile specimens were chosen to better understand the “ductile-brittle transition” associated with hydrogen content and hydrogen pressure. The purpose of the present investigation is to understand the synergistic effect of hydrogen gas and internal hydrides on the mechanical properties of ZIR-CALOY-4. The results showed that for both uncharged and hydrided specimens, the notch tensile strength decreased with increasing hydrogen pressure as well as increasing temperature. Compared with uncharged specimens, the specimens with hydrides had lower values of notch tensile strength. A ductile-brittle transition was found on specimens tested at 25 掳C and at hydrogen pressures between 0 and 1010 kPa. For the specimen containing 220 ppm H, the reduction of area (RA) at 25 掳C and at hydrogen pressures of 1010 kPa and above was drastically reduced, resulting in almost completely brittle behavior. This hydrogen and hydride-induced cracking was found to be an autocatalytic process. From the fractographic finding, the ductile-brittle transition was closely related to the precipitation and distribution of brittle hydrides. The ductile-brittle transition disappeared as the temperature increased to 100 掳C and above. This can be attributed to the improved ductility of the zirconium matrix with increasing temperature.