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

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 degrees and 45 degrees) using a laser-based powder bed fusion and subsequently subjected to two heat treatments: (i) direct aging at 170 degrees C for 2 h (A170) and (ii) stress relief at 300 degrees 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 degrees C and direct aging at 170 degrees C, both for up to 10 h. It was found that aging at 170 degrees C for 2 h resulted in higher hardness, yield strength, and ultimate tensile strength than aging at 155 degrees 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 degrees and 45 degrees) slightly affect the high cycle fatigue properties.