On the relationship between indentation hardness and modulus, and the damage resistance of biological materials.

摘要: Abstract The remarkable mechanical performance of biological materials is based on intricate structure–function relationships. Nanoindentation has become the primary tool for characterising materials, as it allows to relate structural changes variations in properties small scales. However, respective theoretical background and associated interpretation parameters measured via indentation derives largely from research ‘traditional’ engineering such metals or ceramics. Here, we discuss functional relevance hardness by presenting a meta-analysis its relationship with modulus. Across seven orders magnitude, was directly proportional Using lumped parameter model deconvolute into components arising reversible irreversible deformation, establish criteria which allow interpret differences across within materials. ratio between modulus arises key parameter, related deformation during indentation, material’s yield strength, resistance material property represents energy required create unit volume purely deformation. Indentation generally increases upon dehydration, however larger extent than expected accompanying modulus, indicating that water acts ‘plasticiser’. A detailed discussion role hardness, toughness damage control sharp blunt yields comprehensive guidelines performance-based ranking suggests quasi-plastic frequent yet poorly understood mode, highlighting an important area future research. Statement Significance Instrumented widespread show approximately constant simple elastic-plastic series employed rationalise part this correlation, meaningful comparison are proposed. emerges relative amount indentation. Despite their comparatively high ratio, susceptible quasiplastic due toughness: hence hypothesised be phenomenon,