The influence of texture on the shape-memory effect in polycrystals

A model is developed to show that texture is a crucial factor in determining the shape-memory effect in polycrystals. In particular, it is established that texture is the reason why the strains recoverable in Ti–Ni are so much larger than those in Cu-based shape-memory alloys in rolled, extruded and drawn specimens. Further, it is shown that both these materials recover relatively small strains in sputter-deposited thin films due to unfavorable texture. It is found that even the qualitative behavior of combined tension–torsion can critically depend on the texture. The results are in good agreement with experimental observations. Finally, textures are suggested for improved shape-memory effect.