Proceedings of the
9th International Conference of Asian Society for Precision Engineering and Nanotechnology (ASPEN2022)
15 – 18 November 2022, Singapore

Powder Reusability of Ti-48Al-2Cr-2Nb Intermetallic in Electron Beam Powder Bed Fusion Process

Pan Wang1,a, Wai Jack Sin1, Mui Ling Sharon Nai1, Fern Lan Ng1, Aloysius Tan1, Min Hao Goh1 and Yusaku Maruno2

1Singapore Institute of Manufacturing Technology, 73 Nanyang Drive, 637662, Singapore

2Materials Solution Centre, Hitachi Metals Singapore Pte. Ltd., Singapore 629656


Metal powder bed fusion additive manufacturing (PBF-AM) has been widely adopted in the aerospace and orthopedic industries. For the powder feedstock used in PBF-AM, the condition of the metal powders affects the quality of the printed parts and the cost of the powder contributes to a significant portion of the overall manufacturing cost. It is not feasible to adopt virgin powder for every single build, therefore, the reuse of the powder feedstock in the subsequent builds becomes an economical method to reduce the cost. However, there is lack of standard methodology for the reusability of powder. In particular, the powder's quality may change with the increase of reuse times, which in turn causes the change of the PBF-AM part's quality. Herein, we evaluate the reusability of Ti-48Al-2Cr-2Nb intermetallic powder in the electron beam powder bed fusion (EB-PBF) process up to 15 times (totally ~ 300 h cumulative build time). The powders' characteristics, chemical compositions, microstructure, and mechanical properties of the EB-PBF parts are investigated to understand the mechanisms attributing to the change in powder quality. It is found that Ti-48Al-2Cr-2Nb powder can be reused up to 15 times without compromising the resultant microstructure and mechanical properties, even though the contaminations are unavoidable. These findings provide an in-depth understanding of the powder-process-microstructure relationship in additively manufactured Ti-48Al-2Cr-2Nb intermetallic samples and can be applied to other alloys with high volatile elemental content (e.g. Al, Mg, Zn, Pb, Mn).

Keywords: Reuse times, TiAl intermetallic, Contaminations, Electron beam melting, Additive manufacturing.

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