Surface flaws control strain localization in the deformation of Cu$\mathrm{\mid }$Au nanolaminates

We carried out matched experiments and molecular dynamics simulations of the compression of nanopillars prepared from Cu$\mathrm{\mid }$Au nanolaminates with 25 nm layer thickness. The stress-strain behavior obtained from both techniques are in excellent agreement. Variation of the layer thickness in simulations reveals an increase of the strength with decreasing layer thickness. Pillars fail through the formation of shear bands whose nucleation we trace back to the existence of surface flaws. Our combined approach demonstrates the crucial role of contact geometry in controlling the deformation mode and suggests that modulus-matched nanolaminates should be able to suppress strain localization while maintaining controllable strength.