Effect of porosity on mechanical properties of porous tantalum scaffolds produced by electron beam powder bed fusion

The effect of porosity on compressive, bending, and tensile properties of the porous tantalum scaffolds fabricated by electron beam powder bed fusion (EB-PBF) was investigated. The porous tantalum scaffolds with porosity from 69% to 77.8% were obtained by varying the designed porosity and adjusting the processing parameters. It is found that the pores and unfused powder decrease with the increase of deposited energy density. The decrease of porosity leads to an improvement in mechanical properties. The relevancy between compressive/bending/tensile yield strength and relative density can be described appropriately by exponential model, while the relationship between elastic modulus and relative density is in good agreement with the Gibson−Ashby model. All the porous tantalum scaffolds exhibit good ductility in compressive, bending and tensile tests. No fragmentation of struts is observed during the compression process, but cracks are formed on the strut surface after 90° bending, mainly due to the high sensibility to defects caused by the oxide.