Abstract An attempt was made to additively manufacture an Al–Fe binary alloy sample with a hypereutectic composition of 15 wt% Fe using a laser powder bed fusion (LPBF) process. The LPBF-built Al–15Fe alloy sample exhibited a microstructure consisting of a number of melt pools in which regions had locally melted and rapidly solidified due to scanning laser irradiation during the LPBF process. The α-Al (fcc) matrix consists of a number of elongated grains with a mean size of approximately 10 μm. These microstructural features correspond well to previous results of Al alloys additively manufactured by the LPBF process. It was found that relatively coarsened stable θ-Al13Fe4 phases with a length of a few micrometers were localized along the melt pool boundaries. Numerous spherical particles of a metastable Al–Fe intermetallic phase were finely distributed within the nanoscale eutectic microstructure consisting of α-Al and metastable Al6Fe phases inside the melt pools. The metastable phase formation corresponds well to the previous results on the rapidly solidified Al–Fe alloys. The refined multiple intermetallic phases produced by the LPBF process contribute to a high hardness of approximately 200 HV. The refined microstructure appeared stable at an elevated temperature of 300 °C. The high microstructural stability would sustain sufficient strength in a hostile environment for long-term periods of service at elevated temperatures above 200 °C. The present results were utilized to discuss the formation sequence of multiple Al–Fe intermetallic phases in rapid solidification by the LPBF process.

中文翻译：

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激光粉末床熔融增材制造过共晶Al-Fe二元合金中多种金属间相的形成

摘要 尝试使用激光粉末床熔融 (LPBF) 工艺增材制造具有 15 wt% Fe 的过共晶成分的 Al-Fe 二元合金样品。LPBF 构建的 Al-15Fe 合金样品表现出由许多熔池组成的微观结构，其中由于 LPBF 过程中的扫描激光照射，这些区域局部熔化并快速凝固。α-Al (fcc) 基体由许多平均尺寸约为 10 μm 的细长晶粒组成。这些显微结构特征与之前通过 LPBF 工艺增材制造的铝合金的结果非常吻合。发现长度为几微米的相对粗化的稳定 θ-Al13Fe4 相沿熔池边界定位。许多亚稳态Al-Fe金属间相的球形颗粒精细分布在熔池内由α-Al和亚稳态Al6Fe相组成的纳米级共晶显微结构中。亚稳相的形成与之前快速凝固的 Al-Fe 合金的结果非常吻合。LPBF 工艺产生的精炼多金属间相有助于实现约 200 HV 的高硬度。细化的微观结构在 300 °C 的高温下表现稳定。高微观结构稳定性将在恶劣环境中保持足够的强度，以在 200 °C 以上的高温下长期使用。目前的结果被用来讨论在 LPBF 工艺快速凝固过程中多个 Al-Fe 金属间相的形成顺序。