Study of Mechanical Strength and Textures of the Mineralized Shells of Bivalves and Gastropods

RAUL EDUARDO BOLMARO; ROMANO TRIGUEROS, P; B ZAEFFERER, S

Foz do Iguaçu

Congreso; 17o Congresso Brasileiro de Engenharia e Ciência dos Materiais- CBECIMAT.; 2006

Mollusks sea shells are mainly built on two crystallographic variants of CO3Ca, aragonite or calcite, embedded in a biological polymer forming a bio-composite. The mineralization proceeds in an oriented manner and the textures can be measured by regular diffraction techniques. The different textures can even be used as fingerprints for genera or species classification. That particular building strategy confers the material a superb strength, highly superior to regular mineral aragonite or calcite samples. The understanding of the possible correlations between strength and textures is the purpose of the current presentation. We measured textures of different species of bivalves. Vickers hardness and strength by the Palmqvist test were also applied together with SEM microstructural observations. Among the bivalves were Amiantis and Venus genera. Both species show aragonitic structure through the whole thickness. Its evolution through thickness is analyzed by Orientation Distribution Function calculations and correlated with elastic constant calculations and hardness and strength measurements.