Constrained martensitic transformation in an in situ lamella TiNi/NbTi shape memory composite

An in situ lamella TiNi/NbTi shape memory composite was obtained by hot-forging and cold-rolling of an as-cast NbTiNi alloy. Scanning electron microscope (SEM) analysis showed that the TiNi lamella achieved micron level. The constrained martensitic transformation of the TiNi phase was investigated by using differential scanning calorimeter (DSC) and thermal dilatation analyzer. Experimental results indicated that the thermal dilatation test could reveal some delicate details of the constrained martensitic transformation and therefore was an important compensation to the traditional DSC measurement. Based on these results, a schematic illustration was presented for elucidating the constrained martensitic transformation of TiNi in shape memory composite.