Fatigue Assessment of Laser Additive Manufactured AlSi12 Eutectic Alloy in the Very High Cycle Fatigue (VHCF) Range up to 1E9 cycles

Abstract

Selective laser melting (SLM) is a novel technique in laser additive manufacturing which uses laser energy to melt powder material according to the geometry of the computer aided design (CAD) model provided to the SLM system. The process uses a layer-wise manufacturing process which ensures that the manufactured parts possess good mechanical properties. The process is specifically suitable for complex geometries and customized parts which otherwise would be costly and, even, impossible to be manufactured using conventional manufacturing processes. However, for the application of the SLM process for aerospace applications, their performance needs to be investigated in very high cycle fatigue (VHCF) region. This study aims at determining the VHCF behavior of the AlSi12 alloy manufactured by the SLM process. Fatigue characterization has been carried out at frequencies of 20 Hz for high cycle fatigue (HCF) range and 20 kHz for the VHCF range until 1E9 cycles. Optical and scanning electron microscopes were used for microstructural and fracture analysis. The results show that the SLM parts outperform that of cast materials. However microstructural features as well as process-induced defects need to be controlled for a reliable fatigue performance.