Non-monotonic transformation kinetics and the morphological stability of phase boundaries in thermoelastic materials

Abstract: "The linear stability of an isothermal two-phase process involving a planar phase boundary of normal type is analyzed. Results are obtained for cases wherein: i. the temperature field is unaltered as a consequence of the disturbance which is imposed, ii. the process is initially static, iii. the phase boundary associated with the process propagates steadily with non-zero velocity. In the first case the linear stability criteria are equivalent to those obtained in a related purely mechanical investigation. In the second case the process is found to be linearly stable. In the last case it is shown that instability can arise under a variety of circumstances. Of particular interest is a case where the kinetic relation is mechanically stable but thermally unstable; in this case the transformation process is unstable with respect to disturbances which include only suitably long waves, implying that a state involving a highly wrinkled interface is favored over one involving a planar interface."