The role of shear deformation in pure tungsten: Mechanical properties and micro-mechanism

Abstract

The effects of shear deformation at 1173 K on the mechanical properties and deformation mechanism of pure tungsten are investigated by molecular dynamics (MD). The results show that the shear deformation of pure tungsten is dominated by dislocation multiplication and slip band deformation. The shear angle has a significant effect on the mechanical properties of pure tungsten. The yield strength is 4.21 Gpa at a shear angle of 11[Formula: see text], and it increases significantly to 11.84 Gpa while the shear angle increasing to 27[Formula: see text]. In the plastic deformation stage, the stress–strain curve shows obvious oscillation due to the interaction of dislocations in the single-crystal tungsten and the effect of strain strengthening. In addition, the evolution of dislocation and twining in the compression system against shear angle indicates the variation of deformation behavior. When the shear angle is 11[Formula: see text], the lengths of dislocation 1/2[Formula: see text] and [Formula: see text] increase to a peak rapidly, which illustrates dislocation strengthening. However, when the shear angle is more than 11[Formula: see text], the decrease of dislocation length and the appearance of twins along [Formula: see text] direction demonstrate the twining accompanied with dislocation tangling, resulting in the additional increase of strength.