Tough metal-ceramic composites with multifunctional nacre-like architecture.

The brick-and-mortar architecture of biological nacre has inspired the development of synthetic composites with enhanced fracture toughness and multiple functionalities. While the use of metals as the "mortar" phase is an attractive option to maximize fracture toughness of bulk composites, non-mechanical functionalities potentially enabled by the presence of a metal in the structure remain relatively limited and unexplored. Using iron as the mortar phase, we develop and investigate nacre-like composites with high fracture toughness and stiffness combined with unique magnetic, electrical and thermal functionalities.

Transparent and tough bulk composites inspired by nacre.

Materials combining optical transparency and mechanical strength are highly demanded for electronic displays, structural windows and in the arts, but the oxide-based glasses currently used in most of these applications suffer from brittle fracture and low crack tolerance. We report a simple approach to fabricate bulk transparent materials with a nacre-like architecture that can effectively arrest the propagation of cracks during fracture. Mechanical characterization shows that our glass-based composites exceed up to a factor of 3 the fracture toughness of common glasses, while keeping flexural strengths comparable to transparent polymers, silica- and soda-lime glasses.

Addendum: Magnetically assisted slip casting of bioinspired heterogeneous composites.

This corrects the article DOI: 10.1038/nmat4419.

Hierarchically roughened microplatelets enhance the strength and ductility of nacre-inspired composites.

Rough interfaces featuring nanoscale asperities are known to play a major role in the mechanics of nacre. Transferring this concept to artificial bioinspired composites requires a detailed understanding about the effect of the surface topography of reinforcing elements on the mechanical performance of such materials. To gain further insights into the effect of asperity size, hierarchy and coverage on the mechanics of nacre-inspired composites, we decorate alumina microplatelets with silica nanoparticles of selected sizes and use the resulting roughened platelets as reinforcing elements (15vol%) in a commercial epoxy matrix.

Magnetically assisted slip casting of bioinspired heterogeneous composites.

Natural composites are often heterogeneous to fulfil functional demands. Manufacturing analogous materials remains difficult, however, owing to the lack of adequate and easily accessible processing tools. Here, we report an additive manufacturing platform able to fabricate complex-shaped parts exhibiting bioinspired heterogeneous microstructures with locally tunable texture, composition and properties, as well as unprecedentedly high volume fractions of inorganic phase (up to 100%).