Core-shell structure: An effective feature for strengthening ZrB2 ceramics

Hot compression behavior of two ZrB2 ceramics containing SiC or WSi2 particles was investigated upon stepwise heating from 1700 to 2100 degrees C under static load in vacuum. Presence of SiC activated notable creep already at 1700 degrees C, owing to diffused silica softening at SiC/SiC interfaces, whilst for WSi2 appreciable deformation occurred only above 1900 degrees C. Limited amount of SiC particles, which is responsible for cavitation, and formation of (Zr,W)B-2 solid solution, able to accommodate high mechanical loads through plastic deformation, are fundamental characteristics to remarkably perform in hot environments. Particularly, dislocation activity in the solid solution plays a fundamental role at ultra-high temperatures. (C) 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.