Strengthening effects of twin interface in Cu/Ni multilayer thin films – A molecular dynamics study

Molecular dynamics (MD) simulations of Cu/Ni multilayers with coherent, semi-coherent and coherent twin interfaces under tension at temperatures of 10K, 100K and 300K are carried out to study the effects of the interfaces on the overall mechanical behavior. The microstructure and evolution of defects are investigated in detail to understand the strengthening mechanisms. It is found that all kinds of interfaces can act as potent impediments to the motion of dislocations. However, only the coherent twin interface shows significant strengthening effects via plastic deformation. The reason is attributed to the fact that the twin interface can absorb inclined dislocations and decrease its density, and therefore strengthen the layered structures. [Display omitted] •Molecular dynamics uniaxial tension simulations are performed to study effects of coherent, semi-coherent and twin interfaces in Cu/Ni multilayers.•Coherent twin interface shows significant strengthening effects via plastic deformation.•Twin interface can absorb inclined dislocations and decrease its density.•Stepped twin boundaries are formed by reactions between dislocations in Cu layers and twin interfaces.