Microstructural control and layer continuity in deformation bonding of metallic laminated composites

An experimental and simulation study is carried out to investigate the microstructure and tensile behavior of the roll-bonded metallic laminated composites incorporating a single hard layer. To control the microstructure, the effect of the hard layer thickness, hard layer material and layer sequence on the layer continuity is investigated in term of the strain partitioning, degree of necking and strain amplification factor. It is found that at low strain regimes, the thickness reduction of different layers is almost identical and the strain is partitioned equally between the layers. At high strain regimes, depending on the thickness and hardness ratio, unstable necks and rupture occur in the hard layer that lead to the strain partitioning between the constituent layers and cause the deformation to be inhomogeneous. Generally, the strain partitioning, degree of necking and strain amplification factor increase with decreasing the thickness ratio and increasing the hardness ratio. Results show that these parameters are affected by changing the layer sequence. Tensile test results reveal that the tensile strength of the fragmented structure is higher than that of the layered or continuous structure. In all cases, the experimental and simulation results are in a good agreement.