Effect of annealing on the strength of Ag/Fe and Ag/Ni super-laminates produced by foil metallurgy

The strength of the super-laminates of Ag/Fe and Ag/Ni was estimated by both tensile tests and Vickers micro-hardness test. The effect of annealing on the strength of super-laminates has been investigated from the viewpoint of the microstructure change at or near the interface in multilayer due to annealing. In the Ag/Fe and Ag/Ni systems, the strength of the super-laminates in the as-rolled condition increased with the decrease of the layer thickness and exceeded 1000 MPa for tensile test and 300 Hv for Vickers hardness test. The strength of all the specimens used in this investigation was increased by annealing at 473 K for 3.7 ks without the collapse of layer structure. It is considered that the high strength of super-laminates is closely related to the microstructure in the interfaces between two components. The increase of the strength by annealing can be considered as the strengthening effect of interfaces with lattice mismatch which is often observed on the epitaxial multilayered composites.