A study was made of microstructural changes, due to deformation-induced twinning, from a macroscopic point of view. This was done within the framework of a general continuum theory which had been developed for treating polymers. A complicated interplay between the storage and dissipation of deformation-energy, and its effect upon the propagation and arrest of twinning, was clarified. The onset of twinning was determined purely by energy considerations. It was shown that the entire constitutive nature of the material could be reduced to the specification of 3 scalar functions which modelled so-called quasi-equilibrium twinning. These were the Helmholtz free-energy potential, the rate of dissipation function, and the activation function. In the dynamic case, where inertial effects could not be ignored, an additional constitutive function for the kinetic energy that was associated with the twinning process had to be specified.

A Phenomenological Model of Twinning Based on Dual Reference Structures A.R.Srinivasa, K.R.Rajagopal, R.W.Armstrong: Acta Materialia, 1998, 46[4], 1235-48