Effect of dislocation channeling on void growth to coalescence in FCC crystals
Abstract
The effect of dislocation channeling - a heterogeneous deformation mode at the grain scale observed in irradiated, quenchedor heavily cold-worked materials - on void growth to coalescence in Face-Centered-Cubic (FCC) crystals is investigated experimentally.Solution Annealed 304L austenitic stainless steel is used as a model FCC material, in a reference state or irradiatedwith protons in order to trigger dislocation channeling deformation mode. Micrometric cylindrical voids drilled using Focused IonBeam (FIB) technique at the grain scale in thin tensile samples subjected to uniaxial stress loading conditions allows a detaileddescription of void growth and coalescence. Compared to the reference state where plasticity appears homogeneous at the voidscale, dislocation channels strongly interact with voids at the irradiated state, especially at low applied strain where characteristiclocalization patterns are observed and described. As applied strain increases, deformation becomes more and more homogeneousat the void scale through gradual activation of secondary channels. Numerical simulations based on FCC crystal plasticity constitutiveequations are performed and compared to experiments. The main experimental features are recovered by the numericalsimulations, but discrepancies remain for both reference and irradiated states. Ductile fracture modeling in materials exhibitingdislocation channeling is finally discussed based on these experimental and numerical results.
Origin : Files produced by the author(s)
Loading...