Single point machining of A205 aluminum: A comparison of cast and additively manufactured materials

Abstract

A205 aluminum is an additively manufacturable alloy that was recently approved for aerospace use. To date, research has focused on finding proper heat treatments and their resulting material properties, but there is a distinct lack of research on how to properly post-process printed parts to meet dimensional requirements. Machining is a commonly used post-processing procedure. This study compares the machinability of cast and additively manufactured (AM) A205 aluminum to find common pitfalls and strategies to overcome them. Here, machinability is determined by the final surface roughness and finish, as well as specific cutting energy and vibrations. These results are explained by microstructural analyses. The study finds that AM A205 aluminum has slightly better machinability than as cast thanks to its clear, consistent tooling marks at a lower speed. This is attributed to the AM sample's higher hardness, 122.5 HV vs. 90.0 HV, and lower ductility because of the small grains and even distributed TiB2 and α-Al solid solution. Overall, the results show that A205 is machinable and that increasing the cutting speed generally improves the surface finish.