The phenomenon of pseudo-elasticity is connected with a phase transition. Its description requires a non-convex free energy and a non-monotone load-deformation curve. Realistic functions like that are too complicated to permit the analytic calculation of phase equilibria and the evaluation of, stability properties of a phase mixture. One has to resort to graphical methods, see [1], or to numerical calculations. However, here we approximate the non-convex free energy by a train of two intersecting parabolae. This simplification enables us to carry out all calculation explicitly and it seems to describe — at least qualitatively — most phenomena observed in pseudoelasticity.