Morphological changes in polycrystalline Fe after compression and release

N. GUNKELMAN; D. TRAMONTINA; E.M. BRINGA; H.M. URBASSEK

JOURNAL OF APPLIED PHYSICS

AMER INST PHYSICS

Lugar: American Institute of Physics; Año: 2015 vol. 117 p. 85901 - 85906

0021-8979

Despite a number of large-scale molecular dynamics simulations of shock compressed iron, the morphological properties of simulated recovered samples are still unexplored. Key questions remain open in this area, including the role of dislocation motion and deformation twinning in shear stress release. In this study, we present simulations of homogeneous uniaxial compression and recovery of large polycrystallineiron samples. Our results reveal significant recovery of the body-centered cubic grains with some deformation twinning driven by shear stress, in agreement with experimental results by Wang et al. [Sci. Rep. 3, 1086 (2013)]. The twin fraction agrees reasonably well with a semi-analytical model which assumes a critical shear stress for twinning. On reloading, twins disappear and the material reaches a very low strength value.