Exploration of MAB phase formation in the Fe-Y-Al-B system using thin film materials libraries

Inspired by the recent theoretical and experimental advancements in MAB phase materials design we investigate the Fe-Y-Al-B system in search for the theoretically predicted (Fe_2/3Y_1/3)₂AlB₂ in-plane ordered MAB phase. We use combinatorial co-sputtering of thin film materials libraries from elemental targets on 100 mm diameter sapphire substrates at 700 °C followed by high-throughput X-ray diffraction and energy dispersive X-ray spectroscopy measurements. Selected samples from the materials libraries are further characterized by transmission electron microscopy and atom probe tomography. The MAB phase Fe₂AlB₂ is realized in thin film form as large, elongated grains imbedded in an Fe-Y-Al-B matrix. However, in contrast to the theoretical thermodynamic stability calculations, no incorporation of Y into Fe₂AlB₂ was detected.