Physical and Thermal Properties of Iron Meteorites below 300 K*

The iron meteorites Canyon Diablo [IAB-MG] and Agoudal [IIAB] are primarily kamacite or taenite based Fe-Ni polycrystalline alloys that solidify from planetary cores over a timespan of t > 10⁶ years via thermal radiation into the vacuum of space. Depending on their Ni composition and cooling rates, iron meteorites crystallize into a fine octahedrite, coarse octahedrite, or hexahedrite crystal structure.

Using resonant ultrasound spectroscopy, the elastic constants (c₁₁, c₂₂, c₄₄) and Young’s modulus were measured as a function of temperature from 10-300 K. These measurements allow a comparison of how Ni percentage, crystallographic structure, and impact history effect the mechanical behavior of these meteorites. Specific heat capacity and thermal expansion measurements permit an analysis of the Grüneisen parameter as a function of the same temperature range.