High porosity (40% to 60%) 316L stainless steel containing well-interconnected open-cell porous structures with pore openness index of 0.87 to 1 were successfully fabricated by binder jetting and subsequent sintering processes coupled with a powder space holder technique. Mono-sized (30 µm) and 30% (by volume) spherically shaped poly(methyl methacrylate) (PMMA) powder was used as the space holder material. The effects of processing conditions such as: (1) binder saturation rates (55%, 100% and 150%), and (2) isothermal sintering temperatures (1000 ^○C to 1200 ^○C) on the porosity of 316L stainless steel parts were studied. By varying the processing conditions, porosity of 40% to 45% were achieved. To further increase the porosity values of 316L stainless steel parts, 30 vol. % (or 6 wt. %) of PMMA space holder particles were added to the 3D printing feedstock and porosity values of 57% to 61% were achieved. Mercury porosimetry results indicated pore sizes less than 40 µm for all the binder jetting processed 316L stainless steel parts. Anisotropy in linear shrinkage after the sintering process was observed for the SS316L parts with the largest linear shrinkage in the Z direction. The Young’s modulus and compression properties of 316L stainless steel parts decreased with increasing porosity and low Young’s modulus values in the range of 2 GPa to 29 GPa were able to be achieved. The parts fabricated by using pure 316L stainless steel feedstock sintered at 1200 ^○C with porosity of ~40% exhibited the maximum overall compressive properties with 0.2% compressive yield strength of 52.7 MPa, ultimate compressive strength of 520 MPa, fracture strain of 36.4%, and energy absorption of 116.7 MJ/m³, respectively. The Young’s modulus and compression properties of the binder jetting processed 316L stainless steel parts were found to be on par with that of the conventionally processed porous 316L stainless steel parts and even surpassed those having similar porosities, and matched to that of the cancellous bone types.

Electron Backscatter Diffraction (EBSD) inverse pole figure (IPF) maps are indispensable techniques for visualizing grain orientations in titanium alloys. However, differentiating the twelve α-phase variants formed during the β → α phase transformation, following the Burgers orientation relationship, presents a challenge due to overlapping colours in IPF maps. This study systematically investigates how α-phase variants are coloured in IPF X, Y, and Z maps, using a Ti-6Al-2Sn-4Zr-2Mo alloy sample fabricated via laser-based directed energy deposition of metals. By analysing the orientations of prior-β grains and their α-phase variants with Burgers orientation relationship, we illustrate why multiple variants share similar colours in IPF maps. Additionally, the correlation between IPF map colour distributions and Schmid factors for basal, prismatic, and pyramidal slip systems is explored, providing insights into slip activation and deformation behaviour. This work clarifies how α-phase variants are represented in IPF maps and addressing common ambiguities in interpreting EBSD data, providing a framework for accurate microstructural characterization. These findings highlight the need for complementary techniques to resolve colour-based limitations of IPF maps and support the design of tailored microstructures for improved mechanical performances.