Multiscale mechanical property correlations in recrystallised LB-PBF stainless steel 316L

This study investigates the relationship between recrystallisation behaviour and mechanical properties of laser beam powder bed fusion (LB-PBF) stainless steel 316L through both uniaxial tensile and shear punch (ShP) testing. Components were built in vertical (90°) and horizontal (0°) orientations and subjected to systematic heat treatments designed to vary temperature (1050–1200 °C) and soak time (75–225 min). Microstructural evolution was characterised by electron backscatter diffraction (EBSD), focussing on grain morphology, recrystallised fraction, and crystallographic texture. Results show that recrystallisation is strongly temperature-dependent, with near-complete recrystallisation above 1150 °C, accompanied by equiaxed grains and increased Σ3 twin boundaries, reducing anisotropy relative to the as-built state. Time played a secondary role, mainly influencing abnormal grain growth. Mechanical testing revealed a clear strength–ductility trade-off, with lower temperatures retaining strength at the expense of elongation, and higher temperatures promoting ductility while reducing yield strength. ShP testing exhibited good repeatability and captured orientation-dependent behaviour consistent with tensile results. Strong correlations between ShP and tensile properties were established, enabling predictive relationships tailored to annealed LB-PBF 316L. These findings confirm ShP as an effective small-scale testing method for AM alloys, providing a practical route for linking local recrystallisation behaviour to bulk mechanical performance.