Improving the performance and sustainability of additively manufactured AlSi7Mg

Abstract

Additive manufacturing represents an increasingly popular group of technologies used to manufacture components in a way that reduces material waste while allowing for a high degree of customisation. Powder bed fusion (PBF) is one such technology used to process metals, allowing significant potential for property control by the manipulation of processing parameters. The popularity of aluminium alloys in a wide range of applications has resulted in its adoption as one of the most popular metals for PBF. Given the excellent processability of aluminium-silicon alloys during PBF these have seen some of the most attention, with AlSi7Mg one of the more popular.

While PBF technology has seen significant development in recent times, its complex nature means that it has not yet reached full maturation. Many processing parameters are relevant to part properties, and great focus has already been placed on laser parameters. This leaves many parameters yet to be fully elucidated and therefore requiring significant investigative work, with the location of parts within the build volume one such parameter. Heat treatments are also commonly applied to additively manufactured parts, however, these are not often tailored for additively manufactured components. The nature of the powder spreading in PBF techniques also raises the question of powder reuse, as how this powder is reused will influence both the behaviour of the powder in the build chamber and the properties of parts manufactured in subsequent builds.

This work aims to improve the understanding of these factors on the properties of additively manufactured AlSi7Mg, by investigating the effects of part placement within the build volume, tailoring heat treatments for additively manufactured AlSi7Mg, and developing a robust powder reuse method justified by more than just ease of powder handling. In combination, these investigations will improve both the part performance and sustainability of this additively manufactured alloy.