Solomon Alexandre P, O'Quinn Eric C, Liu Juejing, Gussev Igor M, Guo Xiaofeng, Neuefeind Joerg, Trautmann Christina, Ewing Rodney C, Baldinozzi Gianguido, Lang Maik K
Department of Nuclear Engineering, University of Tennessee, Knoxville, TN 37996, USA.
Department of Chemistry, Washington State University, Pullman, WA 99164, USA.
Sci Adv. 2025 Jan 3;11(1):eadq5943. doi: 10.1126/sciadv.adq5943. Epub 2025 Jan 1.
Metastable phases can exist within local minima in the potential energy landscape when they are kinetically "trapped" by various processing routes, such as thermal treatment, grain size reduction, chemical doping, interfacial stress, or irradiation. Despite the importance of metastable materials for many technological applications, little is known about the underlying structural mechanisms of the stabilization process and atomic-scale nature of the resulting defective metastable phase. Investigating ion-irradiated and nanocrystalline zirconia with neutron total scattering experiments, we show that metastable tetragonal ZrO consists of an underlying structure of ferroelastic, orthorhombic nanoscale domains stabilized by a network of domain walls. The apparent long-range tetragonal structure that can be recovered to ambient conditions is only the configurational ensemble average of the underlying orthorhombic domains. This structural heterogeneity with a distinct short-range order is more broadly applicable to other nonequilibrium materials and provides insight into the synthesis and recovery of functional metastable phases with unique physical and chemical properties.
当亚稳相通过各种加工途径（如热处理、晶粒细化、化学掺杂、界面应力或辐照）在动力学上被“捕获”时，它们可以存在于势能景观中的局部最小值内。尽管亚稳材料在许多技术应用中很重要，但对于稳定过程的潜在结构机制以及由此产生的缺陷亚稳相的原子尺度性质却知之甚少。通过中子全散射实验研究离子辐照和纳米晶氧化锆，我们发现亚稳四方ZrO由铁弹性正交纳米尺度畴的底层结构组成，该结构由畴壁网络稳定。可以恢复到环境条件的明显长程四方结构只是底层正交畴的构型系综平均值。这种具有独特短程有序的结构异质性更广泛地适用于其他非平衡材料，并为具有独特物理和化学性质的功能性亚稳相的合成和恢复提供了见解。
