engleski

Microhardness of the nacreous and prismatic seashell’s structures

The engineering cellular and composite materials (biomimetic) draw the inspiration for new development or improvement of properties. The nacreous, cross-lamellar and prismatic structures of seashells are especially interesting for analysis. The inner layer has a nacreous structure composed of aragonite platelets surrounded with an organic phase and in the outer layer a polygonal prismatic structure with very high ratio length/width has been determined. Nano- and micro-indentation gives valuable information about mechanical response particularly by compression, but also by tensile and shear load. The Vickers microhardness of Pinna Pectinata (Pinnidae) Adriatic Sea mollusc shells structure has been determined as a function of the indentation load and loading direction. The load dependence of microhardness is analyzed by using the known Meyer Law and modified proportional specimen resistance (PSR) model. The best correlation between measured values and used models is achieved by using the modified PSR model. The results show that the measured microhardness depends on the load for the nacreous and prismatic structures, except for the prismatic ones indented perpendicularly to the outer surface.

microhardness; indentation size effect; seashell structures

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