Making Gd2O3 nanofibers flexible by grain-boundary toughening

Abstract

Oxide ceramics serve as crucial functional structural materials with vast applications across multiple domains of human production and everyday life. However, their inherent brittleness and heightened susceptibility to defects render them prone to failure under external stresses. Here, a grain-boundary toughening strategy is employed to construct Gd₂O₃ nanofibers (GNFs), which exhibit remarkable mechanical properties such as stretchability, bendability and even knotability. By leveraging the disparity between grain boundary diffusion and grain boundary migration dynamics, we delicately reduce the grain size and increase grain boundary barriers within GNFs. The tightly interlocked fine grains and soft grain boundaries significantly enhance the flexibility of GNFs. The resultant GNFs exhibit remarkable homogeneity, solidity, and pliability, while showcasing an exceptional elastic strain capacity of up to 2.3%. They can endure hundreds of bending cycles without displaying noticeable deformation. This investigation elucidates a fresh and effective strategy for developing robust and flexible oxide ceramic materials.