Deformation of polycrystalline iron up to 30 GPa and 1000 K

Angle-dispersive radial X-ray diffraction measurements were conducted on α- and ϵ-Fe under nonhydrostatic stress conditions up to 30 GPa and 1000 K in laser heated diamond anvil cells. α-Fe (bcc) is found to develop preferred orientation compatible with observations under ambient conditions. The preferred orientation of the α-phase is inherited by the ϵ-phase (hcp) in accordance with the Burgers orientation relationship. A comparison between the observed texture in ϵ-Fe with results from polycrystal plasticity modeling suggests that the predominant deformation mechanisms are basal slip (0 0 0 1)〈1̄ 2 1̄ 0〉 and prismatic slip {1 0 1̄ 0}〈1̄ 2 1̄ 0〉, presumably associated with minor mechanical twinning. We do not observe any evidence of slip on the {1 1 2̄ 2}〈1 1 2̄ 3〉 system that was proposed based on analogies with Cr–Ni stainless steel. Finally, we do not observe any change in preferred orientation upon heating in situ at 28 GPa and 1000 K.