Flash sintering of armor materials: Challenges and opportunities

Flash sintering has been found to enable rapid densification of a wide range of ceramics at lower processing temperatures and shorter times than conventional sintering. This is of particular interest for materials that are difficult to conventionally sinter, including those used in ceramic armor systems, such as B4C, SiC, and B6O. However, the driving mechanisms behind flash sintering are still hotly debated, and the interactions between the processing parameters and the materials being sintered are only in the early stages of being explored. Furthermore, there has been little documented effort to flash sinter these materials and characterize the process. The Army Research Laboratory strategy for research on flash and field-enhanced sintering of ceramics is described, with particular focus on the challenges and opportunities for sintering boron carbide and other relevant armor materials. The design of a scalable flash sintering apparatus and the observed effects of various process parameters such as contact mechanism, atmosphere, current/voltage profile, and part shape as they relate to flash and densification behavior are discussed. This research was supported in part by an appointment to the Postgraduate Research Participation Program at the U.S. Army Research Laboratory administered by the Oak Ridge Institute for Science and Education through an interagency agreement between the U.S. Department of Energy and USARL. Research was sponsored by the Army Research Laboratory and was accomplished under Cooperative Agreement Number W911NF-16-2-0050-P0003. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the Army Research Laboratory or the U.S. Government. The U.S. Government is authorized to reproduce and distribute reprints for Government purposes notwithstanding any copyright notation herein. The research reported in this document was performed in connection with contract/instrument W911QX-16-D-0014 with the U.S. Army Research Laboratory. The views and conclusions contained in this document are those of SURVICE Engineering and the U.S. Army Research Laboratory. Citation of manufacturer\u27s or trade names does not constitute an official endorsement or approval of the use thereof. The U.S. Government is authorized to reproduce and distribute reprints for Government purposes notwithstanding any copyright notation hereon