Dynamics of Martensitic Interfaces

Abstract

The basic dynamic behavior of martensitic interfaces has been analyzed within the framework of lattice dislocation dynamics. Two limiting cases of the martensitic interface structure have been considered: (a) the case when the interface can be appropriately described in terms of an array of non-interacting (well-spaced) interfacial dislocations and; (b) the case when the interfacial dislocations are so closely spaced that the interface can be approximated by a continuous distribution of dislocations. In the first case, it was demonstrated that, after the inclusion of a "chemical" driving force in the equation of motion, the dynamics of lattice dislocations can be directly applied to analyze the interfacial dynamics. In the second case, on the other hand, while the lattice dislocation dynamics is still quite relevant, several parameters in the equation of motion have to be redefined to reflect the fact that the interface now acts as a planar defect. For both of the cases of interfacial dislocation structure, we have analyzed the two basic modes of interfacial motion: (a) the continuous mode in which the motion is controlled by various energy-dissipative processes (e.g., phonon and electron drag) and; (b) the discontinuous or jerky mode in which the motion is controlled by the thermal activation of the interface/obstacle interactions.