Fracture analysis in directed energy deposition (DED) manufactured 316L stainless steel using a phase-field approach

Abstract

Experimental and numerical study regarding fracture in laser-processed steel components is addressed in the present work. Samples of stainless steel (SS) 316L were obtained by an additive manufacturing process, the directed energy deposition (DED), using different deposition orientations, and tested experimentally until fracture. Microstructural investigations, prior and after fracture, were performed by observing micro-cavities and porosities and fractographic images of the fracture surfaces.A numerical approach based on the phase-field diffusive model was utilised in a micromechanical pressure-dependent plasticity context using Rousselier damage criterion and implemented within the finite element framework. The ability to predict the material failure induced by the porosity evolution through the micro-void growth mechanism is considered as a key feature of the proposed material model. The performance of the numerical model is assessed via material deformation analysis, including initiation and propagation of cracks, which are found to be in good agreement with the experimental and fractographic observations from the fabricated tensile test samples.