Effects of processing tempetature on microstructures and mechanical behaviours of reactive hot-pressed SiC(SCS-6)/Ti/ZrB2-ZrC hybrid composites

摘要

In this study, hybrid composites comprising SiC(SCS-6)/Ti composite and ZrB2-ZrC ceramics were prepared by sandwiching Ti/SiC(SCS-6)/Ti sheets and Zr+B4C powder layers, followed by reactive hot pressing (RHPing) between 1250 degrees C and 1400 degrees C. The effects of RHPing temperature on the microstructures and the mechanical behaviours of the composites were examined. For the samples prepared at 1250 degrees C and 1300 degrees C, a Ti-rich zone was observed in the matrix and around the fibres. However, for the sample prepared at 1400 degrees C, no Ti-rich zone was observed. In addition, the hybrid composites show non catastrophic fracture behaviour, irrespective of RHPing temperature. Compared to the sample processed at 1400 degrees C, the samples processed at 1250 degrees C and 1300 degrees C exhibited higher flexural strength and greater damage tolerance. The lower strength and damage tolerance for the composite processed at 1400 degrees C are attributed to stronger interface bonding via significant degradation of the C-rich coating and to strength degradation of the fibres. (C) 2016 Elsevier Ltd. All rights reserved.