Kinetics of Some Displacive Solid - Solid Phase Transformations under Isobaric-Isothermal Conditions

The research activities in the area of the kinetics of pressure induced solid -> solid phase \ntransformations are discussed in this paper . The experimental techniques for obtaining the kinetics data under isobaric-isothermal conditions using the resistometric method are described. The transformations investigated are the a -> to in Ti, fcc -* bcc in Yb and hcp -> fcc in TI . These transformations exhibit features characteristic of a thermally activated nucleation and growth behaviour. The activation volume, the activation entropy and the activation enthalpy obtained from the analysis of the kinetics data are compared . The implications of the kinetics data on the transformation start pressure and the thermodynamic equilibrium pressure are discussed . \n