Europhys. Lett., 60 (2) , pp. 234-240 (2002)
Chaotic and power law states in the Portevin-Le Chatelier effectM. S. Bharathi1 and G. Ananthakrishna1, 2
1 Materials Research Centre, Indian Institute of Science, Bangalore-560012, India
2 Centre for Condensed Matter Theory, Indian Institute of Science Bangalore-560012, India
(Received 5 March 2002; accepted in final form 31 July 2002)
Recent studies on the Portevin-Le Chatelier effect report an intriguing crossover phenomenon from a low-dimensional chaotic to an infinite-dimensional scale-invariant power law regime in experiments on CuAl single crystals and AlMg polycrystals, as a function of strain rate. We devise a fully dynamical model which reproduces these results. At low and medium strain rates, the model is chaotic with the structure of the attractor resembling the reconstructed experimental attractor. At high strain rates, power law statistics for the magnitudes and durations of the stress drops emerge as in experiments and concomitantly, the largest Lyapunov exponent is zero.
62.20.Fe - Deformation and plasticity (including yield, ductility, and superplasticity).
05.45.Ac - Low-dimensional chaos.
05.45.Df - Fractals.
© EDP Sciences 2002