Abstract Formation of Al13Fe4 and the phase transformations on these particles between numbers of different types of Fe-containing intermetallic compounds (FIMCs) were observed in Al–20Si-0.7Fe alloy when solidified at a slow cooling rate (0.01 K/s). The experimental results show that the Al13Fe4 phase (monoclinic) solidified initially and transformed into an intermediate α-Al8Fe2Si (hexagonal) and nano-scaled α-Al grains via a quasi-peritectic reaction. Subsequently, the intermediate α-Al8Fe2Si transformed into β-Al5FeSi (monoclinic). The transformed β-Al5FeSi phase contained many defects, and with heat treatment (530 °C for 30 min) transformed into δ-Al4FeSi2 (tetragonal). The variation in the composition and the lattice parameters of these FIMCs was examined with TEM which shows that the phase transformation among FIMCs starts from FIMCs with lower Si content and process to FIMCs with higher Si content. The interfaces between each of these phases were examined to determine the orientation relationships between various FIMCs. The phase transformation mechanism and the FIMCs transformation sequence have been proposed based on the experimental investigation.

中文翻译：

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Al-20Si-0.7Fe合金中θ-Al13Fe4的形成和α-Al8Fe2Si、β-Al5FeSi和δ-Al4FeSi2的多步相变

摘要 在 Al-20Si-0.7Fe 合金中，当以缓慢的冷却速率 (0.01 K/s) 凝固时，观察到 Al13Fe4 的形成以及这些粒子在不同类型的含铁金属间化合物 (FIMC) 之间的相变。实验结果表明，Al13Fe4 相（单斜晶）最初凝固，并通过准包晶反应转变为中间体 α-Al8Fe2Si（六方晶）和纳米级 α-Al 晶粒。随后，中间体 α-Al8Fe2Si 转变为 β-Al5FeSi（单斜晶系）。转变后的 β-Al5FeSi 相含有许多缺陷，经过热处理（530°C 30 分钟）转变为 δ-Al4FeSi2（四方）。用 TEM 检查这些 FIMC 的组成和晶格参数的变化，这表明 FIMC 之间的相变从具有较低 Si 含量的 FIMC 开始，然后再到具有较高 Si 含量的 FIMC。检查每个相之间的界面以确定各种 FIMC 之间的取向关系。在实验研究的基础上，提出了相变机理和 FIMCs 转换序列。