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)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-orignized critical state.