Rheology of ɛ-iron up to 19 GPa and 600 K in the D-DIA



[1] Stress-strain curves, i.e., relations between the differential stress and macroscopic sample strain, of polycrystalline ɛ-iron have been obtained at pressures of 17(±1) GPa, three different temperatures (600, 400, and 300 K), and various strain rates between 3.8 × 10−6 and 2.3 × 10−5 s−1 using the deformation-DIA coupled with monochromatic X-rays. Five independent stress-strain curves were obtained on axial shortening and the sample exhibited ductile behavior in all. Above 4% axial strain, sample stresses reach saturation and the sample exhibited steady-state deformation. Stress exponents at temperatures of 400 and 600 K were determined to be ∼31 and ∼7, respectively. These results indicate that ɛ-iron deforms in plasticity regime below 400 K and that the dominant deformation mechanism at 600 K may be low temperature power-law creep. The overall deformation behavior for ɛ-iron is consistent with that of zinc, suggesting that the deformation mechanism map of ɛ-iron resembles those of other hexagonal metals.