Indexed by:Journal Article

Date of Publication:2016-11-01

Journal:INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS

Included Journals:Scopus、EI、SCIE

Volume:60

Page Number:68-74

ISSN:0263-4368

Key Words:Ultra-high temperature ceramics; Colloidal process, fracture toughness; Fiber-toughened ceramic composites

Abstract:Ultra-high temperature ceramics are potential materials for a variety of high temperature applications because of excellent thermo-mechanical properties and oxidation resistance. To further improve their fracture properties, a novel colloidal process was proposed to fabricate the short carbon fiber-toughened ZrB2-ZrSi2 composites. Microstructure analysis found that the colloidal processing route could avoid the fibers' agglomeration and alleviate the fibers' damage, which minimizes the structural defects and retains the fibers' strength. The relative density of composites achieves 98.35% and the distribution of fibers in matrix is homogeneous. Mechanical tests indicate that the flexural strength is 458 MPa and the fracture toughness is 6.9 MPa.m(1/2). In comparison to the composite obtained by conventional processing route, the fracture toughness increases by 47%. The main mechanisms for improved fracture properties could be attributed to the crack deflection, fiber sliding and fiber bridging. (C) 2016 Elsevier Ltd. All rights reserved.