| Numéro |
J. Phys. Colloques
Volume 42, Numéro C5, Octobre 1981
ICIFUAS-7Seventh International Conference on Internal Friction and Ultrasonic Attenuation in Solids |
|
|---|---|---|
| Page(s) | C5-1147 - C5-1152 | |
| DOI | https://doi.org/10.1051/jphyscol:19815177 | |
Seventh International Conference on Internal Friction and Ultrasonic Attenuation in Solids
J. Phys. Colloques 42 (1981) C5-1147-C5-1152
DOI: 10.1051/jphyscol:19815177
DEVELOPMENT OF A SURFACE ULTRASONIC WAVE TECHNIQUE FOR THE STUDY OF H ENTRY INTO METALS
E. Lunarska1 et N.F. Fiore21 Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland
2 Department of Metallurgical Engineering and Materials Science, University of Notre Dame, Notre Dame, IN 46556, U.S.A.
Abstract
Rayleigh acoustic waves were propagated along the surface of sheet samples of Ni and Fe alloys during cathodic charging. The waves were propagated at frequencies from 2 to 8 MHz, and their velocity and attenuation were measured. Attenuation and velocity both decreased during charging, and then increased again after the charging current was removed. These effects could arise from H entering solid solution or from such extraneous phenomena as the influence of bubbles on wave propagation, the formation or decomposition of films on the metal or polarization effects in the electrolyte. A series of experiments are described which establish that the attenuation and velocity changes were in fact due to H entry upon charging and H egress after charging. The process dominating the changes is the interaction of H atoms with dislocations within the outer 100 to 1000Å of the sample surface region.