Computational studies of intergranular stress corrosion crack propagation and the role of bridging ligaments

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Computational studies of intergranular stress corrosion crack propagation and the role of bridging ligaments

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Publication Conference Paper, other
Title Computational studies of intergranular stress corrosion crack propagation and the role of bridging ligaments
Author(s) Jivkov, Andrey ; Stevens, N.P.C. ; Marrow, T.J.
Date 2005
English abstract
Previously reported high resolution X-ray tomographic observations of intergranular stress corrosion crack growth in sensitised austenitic stainless steel provided evidence that non-sensitised special grain boundaries form crack bridging ligaments along the crack surface. Two and three-dimensional meso-scale computational models of microstructure have been developed, both demonstrating that the phenomenon can be simulated and studied numerically. As 3D models have limitations in terms of computational power and time, full scale studies of the influence of the various model parameters, are reasonable on 2D models at present. A 2D computational model capable of mimicking the real 3D behaviour with crack bridging is presented and used as a simulation tool in this contribution. In terms of geometrical and physical description of the polycrystalline material, this model follows the framework of 2D percolation models used earlier. The material is described as an assembly of regular hexagonal cells, each of which substitutes one grain. The grain boundaries in the assembly are classified in a binary fashion as being either resistant or susceptible to corrosion. In mechanical terms these two types differ in their failure mode. The resistant boundaries are capable of developing inelastic deformations, while susceptible boundaries are assumed pre-oxidised and able to fail in a brittle manner. Crack propagation is a result of a sequence of grain boundaries failures decided from finite element calculations for equilibrium of the assembly with prescribed boundary conditions. Several experimentally determined fractions of resistant boundaries are considered. A number of random distributions of these in the assembly are studied. Results demonstrate crack propagation with branching and bridging comparable qualitatively to experimental observation. The influence of crack bridging on local crack driving force for various resistant boundaries fractions as well as susceptible and resistant boundaries strengths is presented and discussed.
Pages 8
Language eng (iso)
Subject(s) Technology
Research Subject Categories::TECHNOLOGY
Note ECI Conference on Micromechanics and Microstructure Evolution: Modelling, Simulation and Experiments, Madrid, Spain 11-16 September, 2005
Handle http://hdl.handle.net/2043/4831 (link to this page)

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