Ductile and brittle material removal mechanisms in natural nacre—A model for novel implant materials

Remarkable Natural Material Surfaces and Their Engineering Potential

“…3.1 , lines the inside of many shells and is also what pearls are made of (Luz and Mano 2009 ). It exhibits immense strength and toughness, though it is primarily composed of aragonite (or calcium carbonate crystals), a fragile ceramic (Espinosa et al 2009 ) that, on its own, is very hard and brittle (Denkena et al 2010 ). The conventional defi nition for ceramics is a compound between non-metallic and metallic elements.…”

“…By deforming elastically and distributing the energy to form many other micro-cracks in neighboring bricks of aragonite, a single crack propagation that would otherwise occur in a homogenous material is prevented, avoiding entire failure of the shell ( Lenau and Hesselberg 2013 ). Furthermore, this even distribution of energy prevents force peaks from occurring and causing failure, increasing hardness and strength (Denkena et al 2010 ).…”

“…Each layer is an aragonite polygonal tablet, with thicknesses ranging from 0.2-1.5 μm and average diameters of 5-20 μm (Denkena et al 2010 ). The arrangement of tablets vary among species of Mollusca, with abalone and other gastropods having columnar nacre, where tablets are arranged in columns, while oysters, mussels, and other bivalves have sheet nacre, where tablets are arranged randomly.…”

Multiscale structure of nacre biomaterial: Thermomechanical behavior and wear processes

“…It exhibits high strength and toughness though it is primarily composed of a hard and very brittle ceramic -so-called aragonite (97%wt.) [7,8]. The well-known nacre's superior mechanical properties lies in its hierarchical structure ( Fig.…”

“…Owing to its natural biocompatibility with human, nacre became an obvious candidate as a possible alternative to existing implant materials [8,23]. Indeed, current implants display a lot of drawbacks which are mainly connected to tribological behavior such as unsatisfactory life time or wear particlesinduced inflammatory reactions, for instance.…”