Influence of as-built surface and heat treatment on the fatigue resistance of Additively Layer Manufacturing (ALM) AlSi10Mg alloy.

Abstract

This work concerns the fatigue resistance of a AlSi10Mg material produced by additive manufacturing, and more precisely the competition between as built manufacturing surface and as-machined surface on the fatigue resistance. Samples were built by a powder-bed process with an EOS-M280 machine using standard in two configurations (0° and 90°) in order to evaluate the impact of building direction on fatigue life. The impact of as-built surface on fatigue behavior is quantified for each specimen configuration. A T6 heat treatment is performed on samples in order to evaluate the impact of microstructure on fatigue behavior. For each configurations, the S-N curves is determined in as-built and T6 materials with a load ratio R= -1. The fracture surfaces are carefully analyzed in order to determine the critical defect size for each sample. A Kitagawa type diagram representing the fatigue limit as a function of the defect size is derived from these measurements. All the results were compared to those obtained in asmachined samples.

High cycle fatigue behavior and life prediction for additively manufactured 17-4 PH stainless steel: Effect of sub-surface porosity and surface roughness

“…The failure occurred in correspondence of loose powder (i.e. partially fused) particles and inhomogeneous regions along the outer layer of the specimens, similar to those reported by Ngnekou et al [43] for NS AlSi10Mg. The coarse surface quality acts as a long and shallow crack having a depth of around 60-80 μm, i.e.…”

“…In addition to such pores, the NS surface condition also contains deep valleys due to the surface roughness, which can introduce stress concentrations and negatively affect the fatigue performance of the material [10,17,26,43]. For the present material, the maximum valley depth measured on the polished sections was approximately 65 μm (see Figure 6a).…”

Fatigue Performance and Impact Toughness of PBF-LB Manufactured AlSi 10Mg

“…It was also suggested that a T6 heat treatment could improve the fatigue life of the material. [11] However, opposing results were reported indicating that the separation and coarsening of Si during heat treatment reduced the material's fatigue life [12]. Furthermore, a study investigated factors limiting the fatigue life of the material and identified porosity associated with oxides as the main concern [13].…”