Twisted-layer boron nitride ceramic with high deformability and strength
Yingju Wu, Yang Zhang, Xiaoyu Wang, Wentao Hu, Song Zhao, Timothy Officer, Kun Luo, Ke Tong, Congcong Du, Liqiang Zhang, Baozhong Li, Zewen Zhuge, Zitai Liang, Mengdong Ma, Anmin Nie, Dongli Yu, Julong He, Zhongyuan Liu, Bo Xu, Yanbin Wang, Zhisheng Zhao, Yongjun Tian
Abstract
. However, there remains a lack of research on the mechanical properties of twisted-layer van der Waals materials, owing to a lack of suitable strategies for making three-dimensional bulk materials. Here we report the successful synthesis of a polycrystalline boron nitride bulk ceramic with high room-temperature deformability and strength. This ceramic, synthesized from an onion-like boron nitride nanoprecursor with conventional spark plasma sintering and hot-pressing sintering, consists of interlocked laminated nanoplates in which parallel laminae are stacked with varying twist angles. The compressive strain of this bulk ceramic can reach 14% before fracture, about one order of magnitude higher compared with traditional ceramics (less than 1% in general), whereas the compressive strength is about six times that of ordinary hexagonal boron nitride layered ceramics. The exceptional mechanical properties are due to a combination of the elevated intrinsic deformability of the twisted layering in the nanoplates and the three-dimensional interlocked architecture that restricts deformation from propagating across individual nanoplates. The advent of this twisted-layer boron nitride bulk ceramic opens a gate to the fabrication of highly deformable bulk ceramics.