LAUSR

The expanding of material library of laser powder bed fusion (L-PBF) is of great significance to the development of material science. In this study, the biomedical Ti-13Nb-13Zr powder was mixed with the tantalum particles (2 wt%–8 wt%) and fabricated by L-PBF. The microstructure consists of a β matrix with partially unmelted pure tantalum distributed along the boundaries of molten pool owing to the Marangoni convention. Because the melting process of Ta absorbs lots of energy, the size of molten pool becomes smaller with the increase of Ta content. The fine microstructure exists in the center of melt pool while coarse microstructure is on the boundaries of melt pool because of the existence of heat-affected zone. The columnar-to-equiaxed transitions (CETs) happen in the zones near the unmelted Ta, and the low lattice mismatch induced by solid Ta phase is responsible for this phenomenon. The recrystallization texture is strengthened while the fiber texture is weakened when the tantalum content is increased. Due to the formation of refined martensite α′ grains during L-PBF, the compressive strengths of L-PBF-processed samples are higher than those fabricated by traditional processing technologies. The present research will provide an important reference for biomedical alloy design via L-PBF process in the future.