Effect of transformation induced plasticity on the mechanical behavior of porous SMAs

The fabrication of porous NiTi Shape Memory Alloy (SMA) from elemental Ni and Ti powders using Hot Isostatic Press (HIP) is presented in this work. Porous NiTi alloys with different porosity levels and different mechanical properties are obtained and analyzed. Their behavior under compressive mechanical loading is modeled using a micromechanical averaging model. The model treats the porous NiTi alloy as a two-phase composite: dense SMA matrix and pores. The behavior of the fully dense SMA matrix is modeled using a thermomechanical model with internal state variables. The development of transformation and plastic strains during the martensitic phase transformation is taken into account. The results from the model are compared with the experimental data.

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