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Title: Use of nanoindentation technique for a better understanding of the fracture toughness of Strombus gigas conch shell

Journal Article · · Materials Characterization
;  [1];  [1];  [1];  [2];  [3]
  1. Groupe de Technologie des Surfaces et des Interfaces, Université des Antilles et de la Guyane, 97 159 Pointe à Pitre, French West Indies, Guadeloupe (France)
  2. Centre Commun de Caractérisation des Matériaux, 97 159 Pointe à Pitre, French West Indies, Guadeloupe (France)
  3. CINVESTAV IPN Unidad Merida, Recursos del Mar, Laboratorio de Biología y Acuacultura de Moluscos, Km 6 antigua Carretera a Progreso, Cp 97310 Cordemex (Mexico)

In this work the nanochemical properties of the composite organomineral biomaterial constituting Strombus gigas conch shell are studied by means of dynamic mechanical analyses associated to nanoidentation technique. The measurements are performed on shell samples presenting different surface orientations relative to the growth axis of the conch shell. The influence of the organic component of the biomaterial on its nanomechanical properties is also investigated by studying fresh and dried S. gigas conch shells. Monocrystalline aragonite is used as a reference. For the understanding of nanochemical behaviour, special attention is paid to the pop in events observed on the load/displacement curves which results from nanofractures' initiation and propagation occuring during the load process. In order to better understand the mechanical properties systematic studies of the structure and morphology are performed using scanning electron microscopy, atomic force microscopy and X-ray diffractometry. The hardness and Young's modulus values measured on bio aragonite samples are close to those of the aragonite mineral standard. This surprising result shows that, H and E values are not related to the bio composition and lamellar structure of the bio aragonite. However, it was found that the organic layer and the micro architecture strongly influence the nanofracture initiation and propagation processes in the samples. Statistic study of the pop-in events can help to predict the macroscopic mechanical behaviour of the material. - Highlights: ► Nanomechanical properties of Strombus gigas conch shell ► Low influence of the crossed lamellar structure on H and E values at the nano scale ► Strong influence of the crossed lamellar on nanocracks initiation ► Correlation between mechanical behaviors at the macro and nano scales.

OSTI ID:
22285026
Journal Information:
Materials Characterization, Vol. 76; Other Information: Copyright (c) 2012 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1044-5803
Country of Publication:
United States
Language:
English