Microstructure Evolution and Mechanical Property Anisotropy of Wire and Arc-Additive-Manufactured Wall Structure Using ER2319 Welding Wires

ER2319 welding wires were used to fabricate a wall structure using CMT-PAdv-based wire and arc additive manufacturing (WAAM). Heat treatment was used after the WAAM process. The microstructure and mechanical property anisotropy before and after the heat treatment were studied. There were three areas with different grain morphology along building direction in the as-deposited wall structure. Microstructure difference was clear between interlayer regions and intra-layer regions both in as-deposited and heat-treated state. Netlike second phases became discontinuous after heat treatment, but pores and Fe-rich phases basically unchanged. Mechanical property presented isotropy before heat treatment because alpha-Al with lower Cu content had low resistance on crack initiation or growth and crack mainly grew via netlike second phases which had no directionality. Mechanical property presented anisotropy after heat treatment because alpha-Al was strengthened and brittle Fe-rich phases which concentrated in interlayer regions played a leading role in crack initiation. Moreover, the tensile loading force along the building direction was perpendicular to interlayer regions. Thus, mechanical properties in building direction were lower than that in deposition direction.

Automated summary

The study focused on the microstructure and mechanical property anisotropy of a wall structure fabricated using ER2319 welding wires and CMT-PAdv-based wire and arc additive manufacturing (WAAM). Heat treatment was applied after the WAAM process, leading to changes in the microstructure and mechanical properties, with netlike second phases becoming discontinuous while pores and Fe-rich phases remained largely unchanged. Further analysis revealed that mechanical properties showed isotropy before heat treatment and anisotropy after heat treatment, with the directionality of crack growth influenced by factors such as alpha-Al content and the presence of brittle Fe-rich phases.