A new form of the coherency energy in pseudoelasticity

Abstract

In some previous papers [1], [2] pseudoelasticity in tensile experiments has been treated thermodynamically under the assumption that the relevant constitutive ingredients are

• (i) a non-convex free energy;

• (ii) coherency between the austenitic and martensitic phase.

The form of the coherency energy was assumed to be proportional to the product of phase fractions of the two phases. Recently Rogers [3] has proposed a slight variation of this ansatz: The factor of proportionality should depend on the transformation strain. This new form of coherence energy is investigated in this paper. An attractive feature of this new assumption is that the strains of the coexisting phases in equilibrium remain unchanged as the transformation proceeds.

The entropy production inside the pseudoelastic hysteresis is explored for various straight (P, d)-curves.

Sommario

Nella modellazione delle trasformazioni martensitiche gioca un ruolo essenziale la rappresentazione dell'energia di coerenza tra le fasi. Seguendo una recente proposta di Rogers, in questo lavoro si investiga una forma di tale energia che dipende dalla deformazione di trasformazione.