Ductile fracture via hydrogen pore mechanism in an aluminum alloy; quantitative microstructural analysis and image-based finite element analysis

Finite element analyses based on 3D images of the microstructure in an aluminum alloy observed by X-ray microtomography (so called image-based finite element analysis=IB-FEA) were performed to assess the influences of microstructures on ductile fracture behavior. The exact microstructural features of the aluminum alloy (i.e. hydrogen pores and particles) were perfectly reproduced in the FE models. The microstructural parameters (e.g. diameter, sphericity, volume of pores/particles) were quantified through a handmade software. IB-FEA provided indirect measure of ductility (or risk of ductile fracture), extracting the damage-/fracture-related values (e.g. z-axis normal stress, stress triaxiality and equivalent plastic strain) through simple elasto-plastic simulations. This made it possible to discuss the microstructure-ductility relationship. Dimensionality reduction of data was performed to filter out the microstructural parameters that do not contribute to ductility by quantitative analysis of the importance of the individual microstructural parameters.