Oxided-dispersion-strengthened (ODS) alloys are promising high-strength materials used in extreme environments such as high-temperature and radiation tolerance applications. Until now, ODS alloys have been developed for reducible metals by chemical processing methods, but there are no commercially available ODS alloys for unreducible metals, namely, Al, Mg, Ti, Zr and so on, owing to the challenge of uniformly dispersing oxide particles in these alloys by traditional techniques. Here we present a strategy to achieve ODS Al alloys containing highly dispersive 5 nm MgO nanoparticles by powder metallurgy, using nanoparticles that have in situ-grown graphene-like coatings and hence largely reduced surface energy. Notably, the densely dispersed MgO nanoparticles, which have a fully coherent relationship with an Al matrix, show effective suppression of interfacial vacancy diffusion, thus leading to unprecedented strength (~200 MPa) and creep resistance at temperatures as high as 500 °C. Our processing approach should enable the dispersion of ultrafine nanoparticles in a wide range of alloys for high-temperature-related applications.

氧化弥散强化（ODS）合金是用于极端环境（例如高温和耐辐射应用）的有前途的高强度材料。迄今为止，已经通过化学加工方法开发了可还原金属的ODS合金，但由于氧化物颗粒均匀分散的挑战，还没有商用的不可还原金属（即Al、Mg、Ti、Zr等）的ODS合金通过传统技术在这些合金中。在这里，我们提出了一种通过粉末冶金获得含有高度分散的 5 nm MgO 纳米颗粒的 ODS 铝合金的策略，使用具有原位生长的类石墨烯涂层的纳米颗粒，从而大大降低了表面能。值得注意的是，密集分散的 MgO 纳米粒子与 Al 基体具有完全共格关系，可有效抑制界面空位扩散，从而在高达 500 °C 的温度下实现前所未有的强度（~200 MPa）和抗蠕变性。我们的加工方法应该能够将超细纳米粒子分散在各种合金中，用于高温相关应用。