Mechanical phase mapping of the Taza meteorite using correlated high-speed nanoindentation and EDX

Abstract

Meteorites have one of the most unique and beautiful microstructures, the Widmanstatten structure. This consists of large, elongated bands which form an intricate octahedral lace of crystalline metal. This structure makes meteorites an ideal case to demonstrate the capabilities of mechanical phase mapping using high-speed nanoindentation. In this work, the mechanical properties and composition of the Taza meteorite were mapped using ∼100,000 indentations to statistically determine the properties of the individual phases. Five microstructural phases were characterized in this meteorite: Kamacite, Plessite, Tetrataenite, Cloudy Zone, and Schreibersite. Mechanical phase identification was confirmed using EDX measurements, and the first direct, point-To-point correlation of EDX and large-scale indentation maps was achieved. Mechanical phase maps showed superior phase contrast to EDX in two phases. An indentation property map or a mechanical phase map using a 2D histogram was used to visualize and statistically characterize the phases and identify trends in their relationships.