Effects of reuse on the properties of tantalum powders and tantalum parts additively manufactured by electron beam powder bed fusion

The cost of additively manufactured tantalum parts can be effectively lowered by reusing or recycling tantalum powder. To evaluate the effects of reuse of the tantalum powder on the properties of tantalum parts and scaffolds, this study investigated the characteristics of tantalum powder during cycling, including oxygen content, particle morphology, apparent density, tap density, and flowability. Besides, the influence of reuse time on the mechanical properties of electron beam powder bed fusion (EB-PBF) fabricated tantalum parts and scaffolds was studied with tantalum powder reused more than 30 cycles. The results indicated that particle size distribution of the tantalum powder was nearly unchanged with the increase of cycle number, accordingly apparent density, tap density, and fluidity. While the powder became less spherical with increasing reuse times and some particles showed noticeable distortion and rough surface after being reused 25 times. Moreover, the oxygen content of the tantalum powder increased progressively with increasing reuse times, leading to the decrease of plasticity of the dense tantalum after 15 reuse cycles, and some potential micro-defects appeared in the tantalum samples fabricated from EB-PBF process. However, the tensile strength of dense tantalum parts was not sensitive to the number of uses within the research range. (paper)