Abstract
Commercially pure titanium usually contains a few tens of ppm hydrogen. In order to investigate the influence of such internal hydrogen on the fatigue characteristics, rotating bending fatigue tests were carried out on two kinds of specimens with different hydrogen contents; one contains 34ppm but the other 3ppm. The fatigue behavior was observed successively using the replication technique. A fatigue crack in each type of specimen initiated along slip bands in the grain and did not show the particular growth behavior related to hydrogen content. However, the higher hydrogen specimen showed the longer fatigue life than the other.
