Martensitic transformation to monoclinic phase in bulk B2-CuZr

Shape memory alloys, like B2-CuZr, are a class of materials that have the ability to recover their original shape when subjected to specific thermomechanical conditions. In this work, we carry out molecular dynamics simulations of bulk B2-CuZr to study its martensitic transformation at atomic level. For this purpose, uniaxial tensile tests are performed at temperatures ranging from 1 K to 600 K. We show that all cases exhibit pseudoelasticity by undergoing phase transition from B2 to monoclinic phase along the {110} planes, instead to an R phase as reported in previous works. We obtain the Bain path employing two different interatomic potentials. One potential exhibits martensitic transformation from B2 to monoclinic to body-centered tetragonal structure, while using the other potential a transition from B2 to monoclinic structure is observed, being absent the body-centered tetragonal phase. Reversibility of this transformation is confirmed by performing uniaxial tensile/compressive tests. Finally, a stress-temperature phase diagram is presented as a tool to estimate the stress required to initiate martensitic transformation of bulk B2-CuZr phases.