Indexed by:Journal Article

Date of Publication:2014-10-01

Journal:MATERIALS & DESIGN

Included Journals:EI、SCIE

Volume:62

Page Number:199-204

ISSN:0261-3069

Key Words:ZrB2; Ceramic composite; Mechanical properties; Toughening mechanism

Abstract:WC-doped ZrB2-ZrSi2 ceramic composites were fabricated by hot pressing at temperatures ranging from 1450 degrees C to 1550 degrees C. The influence of ZrSi2 content on the mechanical properties of the composites was investigated by means of three point bending test and single edge notched-beam test, respectively. The microstructure and phase composition were characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD) analysis. The results revealed that: (i) the highest relative density was 99.5% for the composite fabricated at 1550 degrees C; (ii) the doping of WC refined the grain size and led to an anisotropic grain growth which was evidenced by the occurrence of elongated grains; (iii) the highest strength and fracture toughness were 585 MPa and 6.87 MPa m(1/2), respectively; (iv) the main toughening mechanism was considered as the pull out of elongated grains and the deflection of cracks. (C) 2014 Elsevier Ltd. All rights reserved.