The large increases in hardness that were observed with decreasing Al layer thickness were analyzed in detail and several simple dislocation mechanisms were proposed to describe the behavior. Strengthening could be explained by assuming that yielding occurred first by forming dislocation loops in the Al layers. The dislocations were constrained by layers of Al3Sc. It was shown that the antiphase boundary energy of the L12 Al3Sc structure could be used to quantify the resistance of the interfaces in the multi-layer structure to dislocation motion and that the thickness of the Al3Sc layer also played an important role in determining the strengthening response.

A Model for Dislocation Behavior during Deformation of Al/Al3Sc (fcc/L12) Metallic Multilayers. M.A.Phillips, B.M.Clemens, W.D.Nix: Acta Materialia, 2003, 51[11], 3157-70