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

• Main Authors: T. Suzudo, K. Ebihara, T. Tsuru
• Format: Article
• Language: English
• Published: AIP Publishing LLC 2020-11-01
• Series: AIP Advances
• Online Access: http://dx.doi.org/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 α-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.