High-strength and ductile glassy-crystal Ni-Cu-Zr-Ti composite exhibiting stress-induced martensitic transformation

We present a Ni-based crystal-glassy composite material having superior strength paired with a considerable ductility of 15%. The formation of a metastable crystalline phase in a glassy matrix during solidification has been proven capable of promoting a strain-induced martensitic transformation leading to enhanced plasticity under compression at room temperature. Underlying mechanisms of plastic deformation are discussed in terms of the interplay between dislocation slip in the crystalline phase and shear deformation in the glassy matrix. We suppose that the strain-induced martensitic inclusions serve as strong barriers for shear band propagation, promoting shear band branching and multiple shear band formation, thus extending the ductility and preventing a premature brittle fracture. The acoustic emission technique has been employed to clarify the kinetics of transformation and stages of plastic deformation.