Fracture resistance of aluminum multilayer composites

The so-called material inhomogeneity effect, which influences the crack driving force in inhomogeneous materials, has recently been found to contribute to the excellent behavior of some fracture resistant biomaterials. The current study aims to transfer these findings to engineering materials, by experimentally investigating the fracture behavior of multilayers consisting of a high-strength aluminum alloy and thin, soft polymer interlayers. Structures in crack divider and crack arrester (CA) configuration are tested. The results show that the structures in CA configuration exhibit a tremendously improved fracture resistance compared to the homogeneous bulk material. The reason is that cracks are completely arrested in the soft interlayers. This effect appears without delamination, i.e. it is basically different from the well-known delamination effect on weak interlayers.