title: Thermal and athermal crackling noise in ferroelastic nanostructures.
abstract: The evolution of ferroelastic microstructures under external shear is determined by large-scale molecular dynamics simulations in two and three dimensions. Ferroelastic pattern formation was found to be almost identical in two and three dimensions, with only the ferroelastic transition temperature changing. The twin patterns generated by shear deformation depend strongly on temperature, with high wall densities nucleating under optimized temperature conditions. The dynamical tweed and mobile kink movement inside the twin walls is continuous and thermally activated at high temperatures, and becomes jerky and athermal at low temperatures. With decreasing temperature, the statistical distributions of dynamical tweed and kinks vary from a Vogel-Fulcher law P(E)~exp-(E/(T-TVF)) to an athermal power-law distribution P(E)~E-E. During the yield event, the nucleation of needles and kinks is always jerky, and the energy of the jerks is power-law distributed. Low-temperature yield proceeds via one large avalanche. With increasing temperature, the large avalanche is thermally broken up into a multitude of small segments. The power-law exponents reflect the changes in temperature, even in the athermal regime.
authors.affiliation: Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, UK. State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China.
authors.forename: Z
authors.initials: Z
authors.lastname: Zhao
authors.forename: X
authors.initials: X
authors.lastname: Ding
authors.forename: J
authors.initials: J
authors.lastname: Sun
authors.forename: E K H
authors.initials: EK
authors.lastname: Salje
mesh_terms: D004548:Elasticity; D006358:Hot Temperature; D007501:Iron / Q000737:chemistry*; D008956:Models, Chemical; D056004:Molecular Dynamics Simulation; D049329:Nanostructures / Q000737:chemistry*; D009622:Noise; D013696:Temperature
chemical_list: D007501:Iron