Simulation of nacre with TiN/Pt multilayers and a study of their mechanical properties

TiN/Pt multilayers with individual layer thickness between 1 and 8 nm have been prepared by ion beam sputtering deposition to simulate the nacreous structure in natural nacre. Both the hardness and toughness were systematically investigated together with a study of structures of the multilayer. It was found that [111] texture developed during the alternative deposition of TiN and Pt. The multilayer toughness was higher than that of pure TiN. The hardness was greater than the volume weighted mean of the hardness of two components (i.e. TiN and Pt). Both the multilayer hardness and toughness showed a strong dependence on the individual layer thickness arrangement. When the individual thickness was properly adjusted, the multilayer can even be harder than its hard component (TiN) while the toughness was also greatly improved. Annealing experiment indicated that such an enhancement was an intrinsic property of the multilayers. Some suggestions for microdesigning of materials are thus proposed.