Ab initiocalculation of tensile strength in iron

A tensile test in ferromagnetic iron for loading in [001] and [111] directions is simulated by ab initio electronic structure calculations using all-electron full-potential linearized augmented-plane-wave method within the generalized gradient approximation. The theoretical tensile strengths and Young's moduli of ferromagnetic iron are determined and compared with those of other materials. The magnetic and elastic behaviours of iron under uniaxial tensile loading are discussed in detail and compared with the results for isotropic tension (i.e. for negative hydrostatic pressure). Marked anisotropy of theoretical tensile strength in [001] and [111] direction is explained in terms of higher-symmetry structures present or absent along the deformation paths.