Youngʹs modulus of nanocrystalline Fe measured by nanoindentation

Nanoindentation techniques were used to measure Youngʹs modulus for nanocrystalline Fe samples produced by inert-gas condensation and warm consolidation. The samples had grain sizes of 4–20 nm and residual porosity of 2–30% calculated relative to conventional Fe. Values of Youngʹs modulus for the nanocrystalline Fe are reduced relative to that of conventional, fully dense Fe. A review of Youngʹs modulus for other nanocrystalline materials showed similar trends. Published results for porous conventional Fe showed similar reductions in Youngʹs modulus for samples with comparable porosity levels. The observed reductions in Youngʹs modulus for both the nanocrystalline and the conventional porous Fe can be described adequately by several theories utilizing spheroidal porosity.