Multifractal burst in the spatiotemporal dynamics of jerky flow

Phys Rev Lett. 2001 Oct 15;87(16):165508. doi: 10.1103/PhysRevLett.87.165508. Epub 2001 Oct 1.


The collective behavior of dislocations in jerky flow is studied in Al-Mg polycrystalline samples subjected to constant strain rate tests. Complementary dynamical, statistical, and multifractal analyses are carried out on the stress-time series recorded during jerky flow to characterize the distinct spatiotemporal dynamical regimes. It is shown that the hopping type B and the propagating type A bands correspond to chaotic and self-organized critical states, respectively. The crossover between these types of bands is identified by a large spread in the multifractal spectrum. These results are interpreted on the basis of competing scales and mechanisms.