Microstructural homogeneity and mechanical behavior of a selective laser melted Ti-35Nb alloy produced from an elemental powder mixture

Document Type

Journal Article

Publication Title

Journal of Materials Science and Technology

Volume

61

First Page

221

Last Page

233

Publisher

Elsevier

School

School of Engineering

RAS ID

32746

Funders

Edith Cowan University Australian Government Research Training Program Scholarship

Comments

Wang, J., Liu, Y., Rabadia, C. D., Liang, S. X., Sercombe, T. B., & Zhang, L. C. (2021). Microstructural homogeneity and mechanical behavior of a selective laser melted Ti-35Nb alloy produced from an elemental powder mixture. Journal of Materials Science & Technology, 61, 221-233. https://doi.org/10.1016/j.jmst.2020.05.052

Abstract

© 2020 Although using elemental powder mixtures may provide broad alloy selection at low cost for selective laser melting (SLM), there is still a concern on the resultant microstructural and chemical homogeneity of the produced parts. Hence, this work investigates the microstructure and mechanical properties of a SLM-produced Ti-35Nb composite (in wt%) using elemental powder. The microstructural characteristics including β phase, undissolved Nb particles and chemical homogeneity were detailed investigated. Nanoindentation revealed the presence of relatively soft undissolved Nb particles and weak interface bonding around Nb-rich regions in as-SLMed samples. Solid-solution treatment can not only improve chemical homogeneity but also enhance bonding through grain boundary strengthening, resulting in ∼43 % increase in tensile elongation for the heat-treated Ti-35Nb compared to the as-SLMed counterpart. The analyses of tensile fractures and shear bands further confirmed the correlation between the different phases and the ductility of Ti-35Nb. In particular, the weak bonding between undissolved Nb and the matrix in the as-SLMed sample reduces its ductility while the β grains in solid-solution treated Ti-Nb alloy can induce a relatively stable plastic flow therefore better ductility. This work sheds insight into the understanding of homogenization of microstructure and phases of SLM-produced alloys from an elemental powder mixture.

DOI

10.1016/j.jmst.2020.05.052

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