Beaudry David C, Waters Michael J, Valentino Gianna M, Foley Daniel L, Anber Elaf, Rakita Yevgeny, Brandenburg Charlie J, Couzinié Jean-Philippe, Perrière Loïc, Aoki Toshihiro, Knipling Keith E, Callahan Patrick G, Redemann Benjamin W Y, McQueen Tyrel M, Opila Elizabeth J, Rondinelli James M, Taheri Mitra L
Department of Materials Science & Engineering, Johns Hopkins University, Baltimore, MD, USA.
Department of Materials Science & Engineering, Northwestern University, Evanston, IL, USA.
Sci Adv. 2024 Sep 20;10(38):eado9697. doi: 10.1126/sciadv.ado9697.
Refractory multiprincipal element alloys (RMPEAs) are potential successors to incumbent high-temperature structural alloys, although efforts to improve oxidation resistance with large additions of passivating elements have led to embrittlement. RMPEAs containing group IV and V elements have a balance of properties including moderate ductility, low density, and the necessary formability. We find that oxidation of group IV-V RMPEAs induces hierarchical heterogeneities, ranging from nanoscale interstitial complexes to tertiary phases. This microstructural hierarchy considerably enhances hardness without indentation cracking, with values ranging between 12.1 and 22.6 GPa from the oxide-adjacent metal to the surface oxides, a 3.7 to 6.8× increase over the interstitial-free alloy. Our fundamental understanding of the oxygen influence on phase formation informs future alloy design to enhance oxidation resistance and obtain exceptional hardness while preserving plasticity.
难熔多主元合金（RMPEAs）是现有高温结构合金的潜在继任者，尽管通过大量添加钝化元素来提高抗氧化性的努力导致了脆化。含有IV族和V族元素的RMPEAs具有适度的延展性、低密度和必要的可成形性等性能平衡。我们发现IV-V族RMPEAs的氧化会引发从纳米级间隙复合物到第三相的分级不均匀性。这种微观结构分级显著提高了硬度且无压痕开裂，从氧化物相邻金属到表面氧化物的硬度值在12.1至22.6吉帕之间，比无间隙合金增加了3.7至6.8倍。我们对氧对相形成影响的基本理解为未来合金设计提供了依据，以提高抗氧化性并在保持塑性的同时获得优异的硬度。
