Jeong Byeongyun, Lahkar Simanta, An Qi, Reddy Kolan Madhav
School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
Department of Materials Engineering, Indian Institute of Technology Gandhinagar, Gandhinagar 382355, India.
Nanomaterials (Basel). 2022 Sep 16;12(18):3228. doi: 10.3390/nano12183228.
Lightweight polycrystalline ceramics possess promising physical, chemical, and mechanical properties, which can be used in a variety of important structural applications. However, these ceramics with coarse-grained structures are brittle and have low fracture toughness due to their rigid covalent bonding (more often consisting of high-angle grain boundaries) that can cause catastrophic failures. Nanocrystalline ceramics with soft interface phases or disordered structures at grain boundaries have been demonstrated to enhance their mechanical properties, such as strength, toughness, and ductility, significantly. In this review, the underlying deformation mechanisms that are contributing to the enhanced mechanical properties of superhard nanocrystalline ceramics, particularly in boron carbide and silicon carbide, are elucidated using state-of-the-art transmission electron microscopy and first-principles simulations. The observations on these superhard ceramics revealed that grain boundary sliding induced amorphization can effectively accommodate local deformation, leading to an outstanding combination of mechanical properties.
轻质多晶陶瓷具有良好的物理、化学和机械性能，可用于各种重要的结构应用。然而，这些具有粗晶结构的陶瓷由于其刚性共价键（通常由大角度晶界组成）而脆性大且断裂韧性低，这可能导致灾难性失效。具有软界面相或晶界无序结构的纳米晶陶瓷已被证明能显著提高其机械性能，如强度、韧性和延展性。在本综述中，利用先进的透射电子显微镜和第一性原理模拟，阐明了有助于超硬纳米晶陶瓷（特别是碳化硼和碳化硅）机械性能增强的潜在变形机制。对这些超硬陶瓷的观察表明，晶界滑动诱导非晶化可以有效地适应局部变形，从而实现优异的机械性能组合。
