Orientation dependence of indentation behavior in Al–SiC nanolaminate composites

• The properties of nanolaminates are highly anisotropic.
• Multiaxial stress state under indenter has implications for anisotropic structures.
• Layer curvature reduces stiffness of multilayer in all orientations.

Al and SiC nanolaminate films were characterized in the perpendicular, inclined and parallel orientations using nanoindentation. The deformation was dominated by buckling of the layers when the layers were parallel to the indenter and by compression of the ductile Al layers when the layers were perpendicular to the indenter, while indentation in inclined orientations showed an intermediate behavior. Finite element modeling (FEM) of indentation deformation using wavy layers showed much more compliant behavior and prominent layer buckling than the idealized flat structure, highlighting the large effect these microstructural details can have on the deformation behavior.