Micromechanics modelling of NiTi polycrystalline aggregates transforming under tension and compression stress

An earlier developed micromechanical model is further elaborated. The model was developed on the basis of detailed knowledge of single crystal behaviours in uniaxial stress-strain-temperature (sigma-epsilon-T) tests. It captures polycrystal thermomechanical responses due to multiple deformation mechanisms derived from martensitic transitions. Simulations of three different types of tests on polycrystalline NiTi are presented and discussed-(i) tension-compression pseudoelastic test, (ii) cooling under constant compressive stress, (iii) recovery stress test in tension. Simulation results for families of particularly oriented grains are intended for comparison with the results of in situ neutron diffraction experiments reported in a companion paper [4]. Unique information on the redistribution of stresses, strains and phase fractions among orientated grains and phases of the transforming polycrystal is obtained. (C) 2004 Published by Elsevier B.V.