Effect of heat treatment on mechanical properties and corrosion resistance of Directed Energy Deposition-Arc 2319 Al alloy

In this study, homogenization + solution aging treatments were applied to Directed Energy Deposition-Arc (DED-Arc) 2319 Al alloy components. The impact of the heat treatment and their influence on microstructure evolution, mechanical properties and corrosion resistance was analyzed. A number of acicular strengthening phases θ′ (Al₂Cu) and θ″ (Al₂Cu) were precipitated by heat treatment. The hardness increased from 73.9 HV (as-deposited state) to 148.0 HV in the aged state. Similarly, the ultimate tensile strength (UTS) in longitudinal direction increased from 254.3 MPa (deposited state) to 371.7 MPa in aged state. The transverse UTS of the samples increased from 257.2 MPa in the deposited state to 383.1 MPa in the aged state. The results of both electrochemical and intergranular corrosion (IGC) tests indicate that heat treatment can enhance the corrosion resistance of the alloy by promoting the dissolution of the secondary phase and the diffusion of elements.