Microstructural Variations in Laser Powder Bed Fused Al-15%Fe Alloy at Intermediate Temperatures

Wenyuan Wang; Naoki Takata; Asuka Suzuki; Makoto Kobashi; Masaki Kato

doi:10.3390/ma15134497

Microstructural Variations in Laser Powder Bed Fused Al-15%Fe Alloy at Intermediate Temperatures

Materials (Basel). 2022 Jun 26;15(13):4497. doi: 10.3390/ma15134497.

Authors

Wenyuan Wang¹, Naoki Takata¹, Asuka Suzuki¹, Makoto Kobashi¹, Masaki Kato²

Affiliations

¹ Department of Materials Process Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan.
² Aichi Center for Industry and Science Technology, 1267-1 Akiai, Yakusa-cho, Toyota 470-0356, Japan.

Abstract

The samples of the Al-15Fe (mass%) binary alloy that were additively manufactured by laser powder bed fusion (L-PBF) were exposed to intermediate temperatures (300 and 500 °C), and the thermally induced variations in their microstructural characteristics were investigated. The L-PBF-manufactured sample was found to have a microstructure comprising a stable θ-Al₁₃Fe₄ phase localized around melt-pool boundaries and several spherical metastable Al₆Fe-phase particles surrounded by a nanoscale α-Al/Al₆Fe cellular structure in the melt pools. The morphology of the θ phase remained almost unchanged even after 1000 h of exposure at 300 °C. Moreover, the nanoscale α-Al/Al₆Fe cellular structure dissolved in the α-Al matrix; this was followed by the growth (and nucleation) of the spherical Al₆Fe-phase particles and the precipitation of the θ phase. Numerous equiaxed grains were formed in the α-Al matrix during the thermal exposure, which led to the formation of a relatively homogenous microstructure. The variations in these microstructural characteristics were more pronounced at the higher investigated temperature of 500 °C.

Keywords: additive manufacturing; aluminum alloys; intermetallics; microstructure; thermal exposure.

Grants and funding

This study was supported by the “Knowledge Hub Aichi,” a Priority Research Project of the Aichi Prefectural Government, Japan; a JSPS KAKENHI grant (no. 20H02462; Japan); and the Light Metal Educational Foundation, Inc. (Japan).