Study of post-heat treatment on homogeneity of microstructures and properties of wire arc additive manufactured components by 308L wires

It is essential to manufacture large-scale components with defect-free and homogeneous microstructure via wire arc additive manufacturing (WAAM). Thermal cycling in WAAM influences grain growth, morphology, and distribution variations leading to inhomogeneity in mechanical properties and corrosion resistance across the manufactured component. The study reveals that post-heat treatment (holding at 1050 °C for 1 h, followed by rapid water quenching) enhances microstructural homogeneity and increases the proportion of high-angle grain boundaries of the component, which is beneficial to reduce crack propagation speed and enhance material ductility. Post-heat treatment is effective for microstructure and property improvement, which is of crucial importance to the manufacturing and application of large-scale WAAM-ed components.