Brittle-fracture simulations of curved cleavage cracks in alpha-iron: A molecular dynamics study

T Suzudo and K Ebihara and T Tsuru, AIP ADVANCES, 10, 115209 (2020).

DOI: 10.1063/5.0026659

Although body-centered-cubic (bcc) metals and alloys are ubiquitous as structural materials, they are brittle, particularly at low temperatures; however, the mechanism of their brittle fracture is not fully understood. In this study, we conduct a series of three- dimensional molecular dynamics simulations of the cleavage fracture of alpha -iron. In particular, we focus on mode-I loading starting from curved crack fronts or the so-called penny-shaped cracks. In the simulations, brittle fractures are observed at cleavages on the 100 plane, while the initial cracks become blunted on other planes as a result of dislocation emissions. Our modeling results agreed with a common experimental observation, that is, 100 is the preferential cleavage plane in bcc transition metals. In addition, dislocation emissions from the crack front were analyzed; the result supported the notion that plasticity in the vicinity of the crack front determines the preferential cleavage plane.

Return to Publications page