Chen Zhuo, Huang Yong, Koutná Nikola, Gao Zecui, Sangiovanni Davide G, Fellner Simon, Haberfehlner Georg, Jin Shengli, Mayrhofer Paul H, Kothleitner Gerald, Zhang Zaoli
Erich Schmid Institute of Materials Science, Austrian Academy of Sciences, A-8700, Leoben, Austria.
Institute of Materials Science and Technology, TU Wien, A-1060, Vienna, Austria.
Nat Commun. 2023 Dec 16;14(1):8387. doi: 10.1038/s41467-023-44060-x.
Tailoring vacancies is a feasible way to improve the mechanical properties of ceramics. However, high concentrations of vacancies usually compromise the strength (or hardness). We show that a high elasticity and flexural strength could be achieved simultaneously using a nitride superlattice architecture with disordered anion vacancies up to 50%. Enhanced mechanical properties primarily result from a distinctive deformation mechanism in superlattice ceramics, i.e., unit-cell disturbances. Such a disturbance substantially relieves local high-stress concentration, thus enhancing deformability. No dislocation activity involved also rationalizes its high strength. The work renders a unique understanding of the deformation and strengthening/toughening mechanism in nitride ceramics.
定制空位是改善陶瓷力学性能的一种可行方法。然而，高浓度的空位通常会损害强度（或硬度）。我们表明，使用具有高达50%无序阴离子空位的氮化物超晶格结构可以同时实现高弹性和抗弯强度。力学性能的增强主要源于超晶格陶瓷中独特的变形机制，即晶胞扰动。这种扰动极大地缓解了局部高应力集中，从而提高了可变形性。不涉及位错活动也解释了其高强度的原因。这项工作对氮化物陶瓷的变形和强化/增韧机制有了独特的理解。
