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The microstructures of materials typically undergo significant changes during shock loading, causing failure when higher shock pressures are reached. However, preservation of microstructural and mechanical integrity during shock loading are essential in situations such as space travel, nuclear energy, protection systems, extreme geological events, and transportation. Here, we report ex situ shock behavior of a chemically optimized and microstructurally stable, bulk nanocrystalline copper–tantalum alloy that shows a relatively unchanged microstructure or properties when shock compressed up to 15 GPa. The absence of shock-hardening indicates that the grains and grain boundaries that make up the stabilized nanocrystalline microstructure act as stable sinks, thereby annihilating deformation-induced defects during shock loading. This study helps to advance the possibility of developing advanced structural materials for extreme applications where shock loading occurs.

Materials in single crystal form are often sought after because the absence of grain boundaries can result in unique properties relative to the polycrystal, but producing these materials is typically a slow and complex process. In this work, pseudo single crystals of the pseudobrookite compound CoTi₂O₅were synthesized by solid‐state reaction from a duplex grain mixture of CoTiO₃and TiO₂. The size of the crystallites was >250 µm. The transformation and subsequent microstructural evolution of the CoTi₂O₅was studied by scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), and X‐ray diffraction (XRD). A novel growth mechanism was identified whereby a single crystal CoTi₂O₅front advances simultaneously along multiple CoTiO₃/TiO₂diphasic boundaries. The single crystal domains were composed of subgrains approximately 5 µm in diameter; differences in the subgrain size and misorientation were related to the growth mechanism and the initial grain size of the duplex CoTiO₃–TiO₂mixture. CoTi₂O₅is a little characterized compound, and this study represents the most significant microstructural study of CoTi₂O₅to date. The findings may be applied to similar pseudobrookite compounds such as MgTi₂O₅and Al₂TiO₅.