scope:

Inappropriate storage conditions for additive manufacturing (AM) metal powder feedstock may negatively affect powder and final AM component properties. There are various storage solutions currently available for metal powders; however, there is no guidance or consensus on which methods are most appropriate and no indication on powder shelf life for selected storage solutions. The aim of this study was to evaluate the consequence of storage conditions on powder properties and AM built part properties to evaluate if storage conditions can minimize the changes in powder and part properties. Three metal powders (titanium alloy [Ti-6Al-4V], nickel alloy [Alloy 718], and aluminum alloy [AlSi7Mg]), commonly used in laser powder bed fusion, were stored for 6 months in a range of storage conditions. The storage conditions included factors such as container type (metal, plastic, or open), container backfill (air or argon), control aids (desiccant, oxygen scavenger, or none), and external environment (BOC/Linde ADDvance inert gas powder cabinet, humidity/temperature controlled lab, or outside). In the second part of the study, electron beam power bed fusion/Ti6-Al-4V powder was stored for 8 months in two industrially relevant storage conditions, in both controlled and uncontrolled temperature and humidity environments. Parts (tensile bars and cubes) were made from each powder batch using a Renishaw AM500M and the part properties were compared. Overall, no effect was found between the two storage conditions investigated on the part properties. However, there was found to be an advantage to using controlled storage environments for Ti-6Al-4V and AlSi7Mg metal powders for maintaining powder flow properties and hydrogen levels, respectively.