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Mollusc shell aragonite-calcite strain profile and phase transition

Project Member(s): Dowd, A., Cortie, M.

Funding or Partner Organisation: Australian Synchrotron Research Program

Start year: 2016

Summary: We propose a new origin of crack resistance in mollusc shell, a remarkably tough natural biomineral: residual stress, which may act to close cracks. Understanding this enhanced toughness could be used by materials engineers to mimic the impressive mechanical properties of biominerals. We have identified mollusc shell aragonite lattice shifts using neutron diffraction and Raman spectroscopy although results were ambiguous as to whether shifts result from residual microscopic stress, macroscopic stress or impurities. We aim to resolve these questions with in situ heating high resolution XRD, to study relaxation of existing microstrain and transformation of the aragonite to calcite.

Publications:

De Silva, KSB, Keast, VJ, Gentle, A & Cortie, MB 2017, 'Optical properties and oxidation of α-phase Ag-Al thin films.', Nanotechnology, vol. 28, no. 9, pp. 095202-095202.
View/Download from: Publisher's site

Keywords: mollusc shell, biomaterials, biogenic ceramic, aragonite, calcite, microstrain, phase transition

FOR Codes: Other Earth Sciences, Condensed Matter Physics, Other Biological Sciences, Materials Engineering, Animal Production and Animal Primary Products, Health, Environment