On the fracture toughness, tensile and failure behaviour of the aluminium alloys ER5183 and ER2319 processed by wire-arc directed energy deposition

Wire-arc directed energy deposition (waDED) offers high flexibility for, e.g., marine and aerospace applications, where the two industrial aluminium filler wires ER5183 and ER2319 are well established for use in welding procedures and can be readily used as feedstock for waDED. However, the mechanical properties of waDED components differ from those produced by conventional processes and therefore require additional characterisation. As fracture toughness is – in addition to strength – a key property for safety–critical components, this study focuses on the evaluation of mechanical properties for waDED ER5183 and ER2319 and relates their mechanical performance to micro- and mesostructural features. Our results indicate that ER5183, an Al-Mg-based alloy, after waDED processing exhibits ∼130 MPa yield strength. Crack growth and failure is dominated by Fe/Mn intermetallic particles and voids, and the crack propagation path strongly deflects along melt pool boundaries, yielding high fracture toughness, K JIc of ∼70 MPa√m. Compared to that, ER2319, an Al-Cu-based alloy, shows a yield strength of ∼235 MPa and K JIc of ∼33 MPa√m in the T6 condition. Here, the crack growth mechanism is governed by Al 2 Cu particles and voids, and crack deflection, akin to ER5183, is primarily impacted by melt pool boundaries. Due to the primarily meso -scale driven crack growth, both alloys exhibit an only minor impact of test orientation on the obtained fracture properties. The relatively higher K JIc values of the waDED-processed alloys compared to rolled material demonstrate the strong potential and relevance of this additive manufacturing technique for safety–critical applications