Virtual processing of hybrid SMA composites through martensitic transformation

The capability of Shape Memory Alloys (SMAs) to modify the reference configuration of an SMA-composite through martensitic transformation is explored. It is intended that through careful selection of a thermomechanical loading path the composite can be "processed" such that the constituent phases are in a preferential reference configuration. Specifically, for materials which have preferred loading conditions (i.e., compression versus tension), such processing results in a residual stress state which takes advantage of the improved properties. The composite under investigation is assumed to be composed of an SMA phase and an elasto-plastic second phase. For analysis of such a composite, a Finite Element (FE) mesh based on a realistic microstructure is constructed by using the results of X-ray tomography. The resultant microstructure is analyzed using FE techniques. It is shown that through an isobaric loading path, transformation generates plastic strains in the elasto-plastic phase which modify the composite reference configuration. The effect of different applied loads is considered.