Void growth and coalescence in single crystals

By K. Sampath, C. Tekoğlu, Florence Scheyvaerts, L. Delannay, Paul Van Houtte, T. Pardoen. 2010

149 citations recorded by the source corpus.

Void growth and coalescence in single crystals are investigated using crystal plasticity based 3D finite element calculations. A unit cell involving a single spherical void and fully periodic boundary conditions is deformed under constant macroscopic stress triaxiality. Simulations are performed for different values of the stress triaxiality, for different crystal orientations, and for low and high work-hardening capacity. Under low stress triaxiality, the void shape evolution, void growth, and strain at the onset of coalescence are strongly dependent on the crystal orientation, while under high stress triaxiality, only the void growth rate is affected by the crystal orientation. These effects lead to significant variations in the ductility defined as the strain at the onset of coalescence. An attempt is made to predict the onset of coalescence using two different versions of the Thomason void coalescence criterion, initially developed in the framework of isotropic perfect plasticity. The first version is based on a mean effective yield stress of the matrix and involves a fitting parameter to properly take into account material strain hardening. The second version of the Thomason criterion is based on a local value of the effective yield stress in the ligament between the voids, with no fitting parameter. The first version is accurate to within 20% relative error for most cases, and often more accurate. The second version provides the same level of accuracy except for one crystal orientation. Such a predictive coalescence criterion constitutes an important ingredient towards the development of a full constitutive model for porous single crystals. (C) 2009 Elsevier Ltd. All rights reserved.

Subfields: Materials Chemistry, Mechanical Engineering, Mechanics of Materials

View Paper: https://www.semanticscholar.org/paper/3926e9ccbaa91636d58a977473b8bd3a35abb2d6

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In Materials Chemistry

In Mechanical Engineering

In Mechanics of Materials

Citations in the corpus

Computational homogenization of elasto-plastic porous metals (2012, unknown): “The proposed computational approach could then be extended to tackle anisotropic properties of the matrix, for instance of pores found in single crystals (see Yerra et al., 2010) and pore size effects in the case of strain gradient plasticity matrix behavior (see Li and Steinmann, 2006).”
Ductile Fracture by Void Growth to Coalescence (2010, background): “Zhang and Ravi-Chandar (2006) used the expanding ring experiment to study necking and fragmentation in an Al alloy with a low rate-sensitivity.”