Characterization of recycled AISI 904L superaustenitic steel powder and influence on selective laser melted parts

Abstract In laser powder-bed fusion processes, excessive metal powder is affected by high laser energy input and contains spatter from the melt pool. Recycled powder therefore can have a negative impact on process quality. In this study, AISI 904L stainless steel powder is recycled up to ten times. The powder is analyzed using scanning electron microscopy and by measuring chemical composition, flowability and particle size distribution in order to examine changes in properties due to recycling. Furthermore, electrical impedance spectroscopy was introduced as a potential method to determine surface oxides on powder particles due to handling and recycling. The recycled powder shows a significant increase in flowability. Furthermore no significant changes of powder properties such as chemical composition and particle size distribution can be found after ten recycling steps, resulting in comparable density and mechanical properties of printed parts. Therefore the present powder material shows an excellent recyclability.