Influence of build orientation and heat treatment on high cycle fatigue of additively manufactured AlSi10Mg

Abstract

This study examines how build orientation and heat treatment affect microstructure and, consequently, the mechanical properties in tensile and high cycle fatigue of additively manufactured AlSi10Mg. Specimens were manufactured in two orientations (0° and 45°) using a laser-based powder bed fusion and subsequently subjected to two heat treatments: (i) direct aging at 170 °C for 2 h (A170) and (ii) stress relief at 300 °C for 2 h (SR300). Two routes for direct aging were previously explored to determine the ideal time and temperature for heat treatment: direct aging at 155 °C and direct aging at 170 °C, both for up to 10 h. It was found that aging at 170 °C for 2 h resulted in higher hardness, yield strength, and ultimate tensile strength than aging at 155 °C for 6 h (A155). Based on the run-out specimens, the specimens subjected to heat treatment A170 exhibited similar stress amplitude at 106 fatigue strength than SR300, with 43.8 MPa and 45.6 MPa, respectively. At similar stress amplitudes, below 106 cycles, the build orientation (0° and 45°) slightly affect the high cycle fatigue properties.