Post-process heat treatment design for tunable strength and toughness in L-PBF 2507 super duplex stainless steel

Laser powder bed fusion (LPBF) of 2507 super duplex stainless steel (SDSS) commonly produces ferrite-rich microstructures with high strength but limited plastic accommodation. This study defines a volumetric-energy-density (VED)-based process window for LPBF 2507 and compares as-printed (AS), stress-relieved (SR), and solution-annealed (SA) conditions using microstructural characterization, mechanical testing, and finite-strain elastoplastic simulation. Near-full-density builds were obtained above approximately 160 J mm −3 . X-ray diffraction (XRD) confirmed ferrite-dominated AS and SR states and supported ferrite peak-broadening analysis, while electron backscatter diffraction (EBSD) quantified phase balance. AS and SR remained strongly ferritic, whereas, among the tested post-processing conditions, SA at 1100 °C/15 min produced an approximately balanced ferrite–austenite phase constitution, with about 51% ferrite and 49% austenite. This transition reduced tensile strength from 1393 MPa in AS to 861 MPa in SA, but increased elongation from 1.15% to 12.57%. Finite-strain J 2 plasticity simulations showed that post-processing mainly modifies yield-stress level, strain localization, and plastic strain accumulation before instability.