Fe-Al compounds are of interest due to their combination of light weight, high strength, and wear and corrosion resistance, but new forms that are also ductile are needed for their widespread use. The challenge in developing Fe-Al compositions that are both lightweight and ductile lies in the intrinsic tradeoff between Al concentration and brittle-to-ductile transition temperature. Here, we show that a room-temperature, ductile-like response can be attained in a FeAl/FeAl₂ layered composite. Transmission electron microscopy, nanomechanical testing, and ab initio calculations find a critical layer thickness on the order of 1 μm, below which the FeAl₂ layer homogeneously codeforms with the FeAl layer. The FeAl₂ layer undergoes a fundamental change from multimodal, contained slip to unimodal slip that is aligned and fully transmitting across the FeAl/FeAl₂ interface. Lightweight Fe-Al alloys with room-temperature, ductile-like responses can inspire new applications in reactor systems and other structural applications for extreme environments.

Fe-Al化合物由于具有重量轻，强度高，耐磨和耐腐蚀的优点而备受关注，但广泛使用还需要具有延展性的新形式。开发轻质且易延展的Fe-Al组合物的挑战在于Al浓度与脆性至延性转变温度之间的内在平衡。在这里，我们表明在FeAl / FeAl ₂层状复合材料中可以获得室温，类似延性的响应。透射电子显微镜，纳米力学测试和从头算计算发现临界层厚度约为1μm，在此之下，FeAl ₂层与FeAl层均匀地共形。FeAl ₂层经历了从多峰含滑移到单峰滑移的基本变化，单峰滑移已对齐并完全穿过FeAl / FeAl ₂界面传输。具有室温，类似延性响应的轻质Fe-Al合金可以激发反应堆系统和极端环境中其他结构应用的新应用。