Abstract
The hydrogen behavior in fatigue and sustained-load cracks growth of a γ-TiAl intermetallic compounds has been studied by means of hydrogen microprint technique. Hydrogen was introduced to a specimen by cathodic charging technique, and then metal-hydride on the charged specimen surface were removed by electropolishing. For the hydrogen microprint technique, specimen surface was covered with collodion and photographic emulsion before pre-cracking. The hydrogen accumulated region was well visualized by the hydrogen microprint technique. It was found that the duration time is the important factor on the hydrogen accumulation behaviour in the fatigue crack growth. In sustained-load crack growth, it was proven that large amount of hydrogen was accumulated in the high stress field at the crack tip. Also it was confirmed that hydrogen content was dependent on the hydrostatic stress.
