SELF-ORGANIZED CRITICALITY OF THE FRACTURE PROCESSES ASSOCIATED WITH HYDROGEN PRECIPITATION IN NIOBIUM BY ACOUSTIC-EMISSION

The statistical analysis of the acoustic signals, emitted by hydrogenated Nb samples during hydrogen precipitation from solid solution, reveals that the distribution of their amplitudes follows the Gutenberg-Richter power law, N(A'> A) is similar to A(-c) with c=0.9 over more than 2 orders of magnitude. This behavior can be considered as evidence that fracture processes due to hydride precipitation in the Nb-H system determine a self-organized critical state.