Wire Arc Additive Manufacturing of Al-Cu Alloy-Grain Refinement, Strengthening and Thermal Simulation

The present study aims to refine the solidification structure of 2319 Al-alloy Wire Arc Additive Manufacturing (WAAM) deposits by adding SiC powder to the interlayer during deposition. The fabricated deposits are subjected to aging treatment. The influence of SiC particle addition and aging treatment on evolution of microstructure and the corresponding hardness and tensile properties was investigated. To enable systematic understanding of the process, thermal simulation using ANSYS has been done for a single layer deposition and compared with the experimental data. The peak temperature for the deposits made with and without SiC particle addition is around 927.53 degrees C and 915.43 degrees C respectively. Three distinct structural zones were clearly seen in as-deposited specimens made without SiC particle addition. However, the deposits with SiC favored the formation of equiaxed grain throughout the specimen. The presence of alpha-Al and theta-Al2Cu phases in the as deposited specimen (without SiC) is confirmed through X-Ray Diffraction (XRD) and Electron Probe Micron Analyzer (EPMA), while the specimen deposited with addition of SiC particles demonstrates the presence of alpha-Al, theta-Al2Cu, and SiC phases. Post-Deposition Heat Treatment (PDHT) aids in uniform formation of theta-Al2Cu precipitates in both specimens. Deposits fabricated with SiC (308 +/- 5 MPa) recorded higher Ultimate Tensile Strength (UTS) in comparison to without SiC deposits (260 +/- 5 MPa). On the other hand, after heat treatment, the as-deposited specimen (without SiC) achieved an UTS of 468 +/- 5 MPa, while the deposit fabricated with SiC recorded an UTS of 484 +/- 5 MPa.