|About this Abstract
||2016 TMS Annual Meeting & Exhibition
||Bulk Processing of Nanostructured Powders and Nanopowders by Consolidation
||Spark Plasma Heat Treated Coarse- and Nano-powder ZrB2-SiC and HfB2-SiC Composites
||Naidu V Seetala, Marquavious Webb, Lawrence Matson, HeeDong Lee, Carmen Carney, Thomas Key
|On-Site Speaker (Planned)
||Naidu V Seetala
ZrB2 and HfB2 with 10-20 wt% SiC were prepared using ultra-sonication, rotary evaporation, and spark plasma sintering (SPS) at high temperatures (~2,000°C) and pressures (35-60 MPa). Positron Annihilation Lifetime Spectroscopy (PALS) results indicate that HfB2 coarse-powder has larger vacancy clusters and nano-pores with lesser concentrations compared to ZrB2 and SiC coarse-powder. The composite with 10wt%SiC has higher hardness compared to 20wt%SiC in both ZrB2-SiC and HfB2-SiC. Nano-composites have higher micro-hardness, lower porosity, and smaller grains compared to coarse-composites. The grain growth is further reduced by lowering the SPS temperature to 1800°C. Large segregates of SiC are observed in coarse-composites those are almost nil in the nano-composites. Nano-powder composite showed remarkable ZrB2 oxidation during SPS which is minimal for coarse-powder composites.
---This work is supported by Air Force Contract FA8650-13-C-5800 and the paper clearance number is 88ABW-2014-3440.
||Planned: A print-only volume