Pseudoelasticity of Cu-Zr nanowires via stress-induced martensitic phase transformations

Atomistic simulations were performed to investigate the pseudoelastic effects induced by martensitic phase transformation from body-centered cubic (B2) to body-centered tetragonal (BCT) lattice in Cu-Zr nanowires. The phase transformation occurs through nucleation and propagation of {100} twin boundary, which differs from the {101} twin boundary for B2 Ni-Al nanowires. During unloading, extension strain up to 45% can be fully recovered through inverse phase transformation. The BCT lattice has also been verified to be metastable for Cu-Zr nanowires with an energy analysis along the epitaxial Bain path. Our work implies Cu-Zr nanowires may be excellent functional components for nanoelectromechanical systems.