Martensitic transformation to monoclinic phase in bulk B2–CuZr

Abstract

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.