Deformation mechanisms and strength in nanoscale multilayer metallic composites with coherent and incoherent interfaces

We investigate the deformation behavior of bimetallic and trimetallic nanoscale multilayer metallic composites under biaxial loading using molecular dynamics. Three types of structures were studied: (a) Cu-Ni fcc/fcc bilayer, (b) Cu-Nb fcc/bcc bilayer, and (c) Ni-Cu-Nb fcc/fcc/bcc trilayer. A configuration with a dislocation structure inside is generated by initially loading a perfect structure to a high strain to nucleate dislocations, then completely unloading it and loading it again. The comparison between the deformation behavior of bilayer and trilayer structures revealed that the Cu-Ni is more ductile, the Cu-Nb is stronger, and the trilayer structure exhibits both high strength and ductility.