fig1

Figure 1. Room-temperature tensile behavior of L-PBF 18Ni300 under different heat-treatment routes: (A) Engineering stress-strain curves for the as-printed, T-480, L-600, and TL-480-600 conditions; (B) Strain hardening behavior quantified by the instantaneous strain-hardening exponent, plotted as a function of true strain. The derivative was evaluated using a backward-difference scheme based on the true stress-strain data after a light smoothing; (C) Ashby strength-ductility map (UTS vs. TEL) for the investigated conditions and selected literature data^[9,38-42]. Triangles, squares, and red circles denote as-printed literature data, aged literature data, and the present work, respectively. Marker colors are used to distinguish different literature sources. Dashed contours denote constant strength-ductility product (UTS × TEL); (D) Schematic of the tensile specimen indicating the gauge (deformed) and grip (undeformed) regions used for microstructural characterization. L-PBF: Laser powder bed fusion; WOF: work of fracture; UTS: ultimate tensile strength; TEL: total elongation.