Abstract
In this study, surrogate pores were designed and generated at specific locations inside tensile specimens fabricated by laser powder bed fusion (L-PBF) processing and further evaluated in porosity characteristics and mechanical properties. The objectives are to demonstrate the feasibility of pore generation and to characterize the pores and examine the effect from various process conditions. The pore-generated specimens were fabricated in an L-PBF system using Ti-6Al-4V (Ti64) powder. Overall, specimens were made using default settings. But, during processing the middle section of the tensile specimens, single track exposures were applied to induce keyhole pores with different energy density levels as well as different scan track numbers and layers. An X-ray computed tomography system was utilized to measure and analyze surrogate pores in the fabricated specimens in pore counts, volumes and sphericity related to process conditions. The results showed that, as expected, pore formation increases with the laser energy density applied and the number of tracks and layers exposed, although individual tracks exhibit a high variability. Specimens evaluated by tensile testing and fractography show that surrogate pores produced in this study so far influence only the ductility of the specimens noticeably, but not Young’s modulus, nor the yield and tensile strengths.
