On the influence of crack front curvature on the fracture behavior of nanoscale cracks
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- 作者：Johannes J. Mö ; ller ; johannes.moeller@fau.de" class="auth_mail" title="E-mail the corresponding author ; Erik Bitzek
- 关键词：Penny-shaped crack ; Semi-brittle fracture ; Twinning ; Cross-slip ; Molecular dynamics simulation
- 刊名：Engineering Fracture Mechanics
- 出版年：2015
- 出版时间：December 2015
- 年：2015
- 卷：150
- 期：Complete
- 页码：197-208
- 全文大小：3100 K
文摘
Atomic-scale fracture processes are traditionally investigated in quasi-2D models of straight, infinite cracks. This approach neglects crack front curvature effects, which might be particularly important for nanoscale crack nuclei in semi-brittle materials. Here we use 3D atomistic simulations to study penny-shaped cracks in body-centered cubic metals. Our results show extensive crack tip plasticity initiated by deformation twinning and followed by emission of screw dislocations which cross-slip along the crack front. Together with the interactions of dislocations and/or twins that are nucleated at differently oriented parts of the crack, these processes determine the fracture behavior of highly curved nanoscale cracks.