Alice  Zehner

Alice Zehner

Scholar Title

MIT CEE | Undergraduate Research and Innovation Scholar

Research Title

Piezo-Raman Analysis of Geological and Biogenic Calcite




Civil and Environmental Engineering

Research Areas
  • Materials Science

Admir Masic


This study focuses on shell material from Australian pearl oyster (Pinctada maxima) and Pen shell (Pinna bicolor) and the biogenic calcite that composes their outer shell. Previous work on biogenic calcite has established its mechanically superior properties to geological calcite, but does not sufficiently model stress dissipation and toughening on the intercrystalline scale. Through piezo-Raman and microindentation techniques, this study visualizes and quantifies the plastic deformation and toughening mechanisms present in biogenic calcite forms. We establish a linear applied stress-vibrational mode shift relationship for geological, P. maxima, and P. bicolor calcite. We then apply these relationships to the Raman maps of depressions made with a microindenter to create correlative maps of residual stress for each tested material. These maps demonstrate that biogenic calcite structures are able to store comparatively high energy and resist cracking with several toughening mechanisms.

I am participating in SuperUROP for the opportunity to develop my independent research skills and to create a body of work that is my own. I look forward to applying the skills I’ve learned in this lab and in my material science coursework to advance the understanding of biological materials.
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