オーステナイト系ステンレス鋼中の水素による内部摩擦

抄録

The temperature dependence of internal friction was measured from 100 to 350 K at a frequency of about 700 Hz for hydrogen-charged 310S, 316 and 304 stainless steels. A characteristic relaxation peak due to dissolved hydrogen was found at about 280 K, on which there is little information in the literature. The characteristics of this 280 K peak are as follows: (1) The internal friction peak grew up with hydrogen charging and went to decay with room-temperature aging, the time responses of which were consistent with a diffusion-controlled process. The peak hight increased not only with the absorbed volume of hydrogen but also with the nickel content of alloys. (2) The peak temperature, in contrast to the peak hight, did not depend much on the absorbed volume of hydrogen and the compositon of alloys. From the relation between peak temperature and test frequency, the activation energy was estimated to be 11.8 kcal/mol and the frequency factor to be 1.3×10¹² s⁻¹. Both of these values agreed quite well with the corresponding values for hydrogen diffusion in austenitic stainless steels. (3) Apparently, the 280 K peak could be regarded as a Snoek-type relaxation occurring in the fcc lattice, which might be explained in terms of the stress-induced reorientation of hydrogen atom pairs or clusters under the influence of nickel in Fe-Cr-Ni alloys.