Influence of volume energy density on the microstructure and properties of parts fabricated by laser powder bed fusion using recycled Ti6Al4V powder blends

Abstract

Laser powder bed fusion (LPBF) is widely used for fabricating complex parts; however, a significant portion of the Ti6Al4V powder remains unused during the process. The efficient recycling of this powder is essential for sustainable development and cost reduction. This paper proposes an optimal mixing ratio of recycled and virgin Ti6Al4V powders to obtain a blend that meets the initial quality requirements for LPBF. Mechanical testing, microscopic characterization, and thermomechanical simulations were conducted to evaluate the effect of the mixed powder on the properties of the as-built parts. The results indicate that volumetric energy density (VED) is a critical parameter governing the mechanical properties and unfused-region-induced defects of parts fabricated from mixed powder feedstocks. Although the optimal VED of the mixed powder was 28.01% higher than that for the virgin powder, the resulting mechanical strength was reduced by approximately 20.41%. This performance difference arises from the higher energy demand of the mixed powder and strict densification requirements, as explained through thermomechanical analyses. This study offers novel insights into reducing cost and ensuring consistent part quality when printing large components.

Keywords

Recovered Ti6Al4V powder / Tensile strength / Volumetric energy density (VED) / Thermomechanical

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Funding

National Natural Science Foundation of China(52422408)

Excel-lent Youth Fund of Liaoning Natural Science Foundation(2023JH3/10200001)

Fundamental Research Funds for the Central Universities(N25BSS021)

RIGHTS & PERMISSIONS

Shanghai University and Periodicals Agency of Shanghai University and Springer-Verlag GmbH Germany, part of Springer Nature