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Copper/aluminium laminates were prepared by roll bonding at 430°C with a 60% rolling reduction in a single pass. Sintering treatments at temperatures between 300 and 500°C were applied to the as-rolled laminates. The interface development and fracture behaviour of the sintered materials were studied. It was found that two major diffusion controlled interface reactions, namely interfacial phase transformations and Kirkendall void formation, occurred in the sintering process. Four different types of phase development were detected in the interface region. As the sintering time and/or temperature increased, the Cu9Al4 phase became dominant. Microhardness measurements confirmed that copper-rich phases possessed higher hardness than the aluminium-rich phases, contributing a higher bond strength. On the other hand, as the sintering time and/or temperature increased, Kirkendall void formation was found to became significant with agglomeration of voids, leading to the formation of a weak layer in the interface region. It was found that the resulting bond strengths of the metal laminates generally increased to maximum values under optimum sintering conditions and then decrease substantially after sintering at high temperatures for prolonged periods.