| The present study is devoted to processing and constitutive modeling of dense and porous SMAs. A novel Spark Plasma Sintering setup is developed, compared to the conventional setup and used for dense/porous NiTi processing. It is characterized by considerably higher current density through the sample at the same total current, as well as drastically decreased heat losses. A 2D axial symmetry electro-thermal Finite Element analysis of the processing zone, in addition to a detailed characterization of the synthesis method and the final product, is also performed. Dense samples (6.17 gcm-3 and 97% NiTi phase) and porous samples (porosity up to 40%) are successfully produced. Another aim of the study is to develop an analytical model for porous SMAs. A set of governing equations for average state variables is rigorously investigated. Moving average technique is used and pore boundary terms that are not well recognized in the continuum mechanics community come into view. |
