Cohesive law describing crack growth at iron/precipitate interfaces

A Elzas and B Thijsse, COMPUTATIONAL MATERIALS SCIENCE, 134, 214-224 (2017).

DOI: 10.1016/j.commatsci.2017.01.042

Single dislocations and dislocation pile-ups at crystalline interfaces cause stress concentrations. This can lead to decohesion of the interfaces under tensile loading. To describe this decohesion quantitatively, a cohesive law for planar crack growth at iron/precipitate interfaces is developed. This cohesive law is based on a universal description of the adhesive energy for different interfaces. Only a single scaling factor c must be applied to convert the prediction based on this universal adhesive energy into the actual traction- separation behaviour during crack growth. This scaling factor takes into account the atomic strain and relaxations. The cohesive law derived here can be implemented in a Discrete Dislocation Plasticity framework to describe crack growth at a larger scale. The method presented in this paper for the derivation of a cohesive law can be applied to other material combinations showing brittle crack growth as well. (C) 2017 Elsevier B.V. All rights reserved.

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