337 / 2019-02-26 18:41:34

Failure and phase transitions in strong ceramics under shock loading

boron carbide,aluminum nitride,silicon carbide,failure model,phase transition,shock compression,smoothed particles hydrodynamics

全体主题 > High Pressure Physics and Materials Science

The improved and adjusted failure model for boron carbide, silicon carbide, and aluminum nitride ceramics is developed on the basis of earlier works of Johnson and Holmquist with using new experimental data. During shock loading these materials experience failure: local structural transformations which significantly reduce material strength. High velocity impact may also induce polymorphic phase transitions in these materials. The velocity of LiF/ceramics interfaces measured in typical plate impact tests are affected much by the aforementioned phenomena. Fortunately, it is possible to take into account all kinds of transformations using the suggested model in a particular simulation, thus providing correct wave structure within the bulk of materials and best agreement with experiments in extremes. The model reveals an interesting structure of failure bands in ceramics which may related to ones observed in the ballistic experiments. One of the most important discoveries made is that strength limit in the failed state of material may vary because of different manufacturing of ceramics samples. The detailed analysis of molecular structure might reveal the reason for it, so the industry would be able to adjust technology for ceramics of better quality.