Measurements were made of H migration, in cryoformed samples, by using a gas-phase permeation technique. The specimens comprised about 90% α'-martensite. It was found that the H diffusivity lay between the values for α- and γ-type steels, and could be described by:

D (cm2/s) = 3.7 x 10-2 exp[-41.4(kJ/mol)/RT]

T.P.Perng, C.J.Altstetter: Scripta Metallurgica, 1984, 18[1], 67-70