Effects of Support Structure Types on Microstructure and Mechanical Properties of Laser Powder Bed Fusion Fabricated Titanium Alloy

Support structures are indispensable for the additive manufacturing process of complex components. However, the influence of different support structure types on component performance remains unclear. In this work, four types of support configurations, namely conical, tree, contoured, and block structures, were designed to investigate their effects on densification, microstructure evolution, and mechanical properties of Ti‐15Mo alloy fabricated by laser powder bed fusion (LPBF). All LPBF‐fabricated samples achieved high relative densities (>98.5%), and the conical support‐assisted sample attained the highest relative density of 99.6%. Microstructural characterizations demonstrated that all samples exhibited refined microstructures consisting of equiaxed and columnar grains. The content of equiaxed grains increased while columnar grains decreased as the cooling rate decreased, which is essentially dominated by the support‐mediated heat dissipation efficiency during the LPBF process. The tensile properties showed significant dependence on support structures, and the sample fabricated with the conical support structure achieved the highest ultimate tensile strength (1123 ± 12 MPa) and ductility (9.0% ± 0.4%), surpassing those of conventionally processed Ti‐15Mo alloys. Furthermore, the intrinsic correlation between the microstructure characteristics and the superior tensile performance was discussed in detail in this work.