M. Nagumo et al., Hydrogen thermal desorption relevant to delayed-fracture susceptibility ofhigh-strength steels, MET MAT T A, 32(2), 2001, pp. 339-347
The susceptibility to hydrogen embrittlement (HE) of martensitic steels has
been examined by means of a delayed-fracture test and hydrogen thermal des
orption analysis. The intensity of a desorption-rate peak around 50 degrees
C to 200 degreesC increased when the specimen was preloaded and more remark
ably so when it was loaded under the presence of hydrogen. The increment ap
peared initially at the low-temperature region in the original peak. As hyd
rogen entry proceeded, the increment then appeared at the high-temperature
region, while that in the low-temperature region was reduced. The alteratio
n occurred earlier in steels tempered at lower temperatures, with a higher
embrittlement susceptibility. A defect acting as the trap of the desorption
in the high-temperature region was assigned to large vacancy clusters that
have higher binding energies with hydrogen. Deformation-induced generation
of vacancies and their clustering have been considered to be promoted by h
ydrogen and to play a primary role on the HE susceptibility of high-strengt
h steel.