Laser Metal Deposition of a Near-Eutectic Al-Ni Alloy

Abstract

Most of the aluminum-based components produced today by additive manufacturing (AM) are based on the Al–Si eutectic system due to its outstanding processability. The mechanical properties of these alloys, however, are well below comparable wrought alloys. Even though successful modifications of the cast and wrought alloys have been performed in the literature, the widespread application is still missing for various reasons. Herein, new alloys of the Al–Ni eutectic system with the composition Al–7.5wt%Ni are manufactured by laser metal deposition (LMD), and the microstructure and properties are described. The microstructure shows a different appearance over the track height: A coarse microstructure can be found at the interlayer boundary. The adjacent fibrous eutectic is followed by a microstructure of twinned dendrites, which only appear at certain process parameters. The appearance of the twinned dendrites is explained via simulations of the local cooling rate of the LMD process. The mechanical properties of samples manufactured by LMD are examined via tensile testing.