Effect of direct metal laser sintering build parameters on defects and ultrasonic fatigue performance of additively manufactured AlSi10Mg

The high cycle fatigue behaviour of additively manufactured AlSi10Mg is evaluated using ultrasonic fatigue as a means to accelerate fatigue testing. Build parameters during the additive manufacturing process are varied, and their effect on defect type, size, and distribution is determined. These defects are further found to influence fatigue behaviour, which is analysed using a Murakami area model. Finally, the ultrasonic fatigue test results are interpreted in the context of applied stress intensity factor and an optimized fatigue limit fit. Two different kinds of physical behaviour, representing Murakami dependence and a long crack regime, are found to better correlate the fatigue life behaviour than the Murakami model alone. With this information, we can tailor defect size, type and distribution, within the context of an optimized processing route, to obtain necessary high cycle fatigue properties.