Hits:

Indexed by:期刊论文

Date of Publication:2012-12-01

Journal:JOURNAL OF THE EUROPEAN CERAMIC SOCIETY

Included Journals:Scopus、SCIE

Volume:32

Issue:16

Page Number:4195-4204

ISSN No.:0955-2219

Key Words:Cooling rate; Eutectic ceramic; Undercooling; Mechanical properties; Microstructure

Abstract:Melt-grown Al2O3/YAG/ZrO2 ternary eutectic samples were solidified by quenching and with controlled cooling rates of 10, 50, and 250 degrees C/min, respectively. Effect of cooling rate on microstructure and mechanical properties were examined. With the increase of cooling rate, three classical characteristic microstructures are obtained and developed from colony structure to dendrite structure and to cell structure. In the quenching process, the sample consists of lamellar eutectic cells and its fracture toughness increases to 4.13 +/- 0.8 MPa m(1/2). The microstructure transitions with the cooling rate are attributed to instability of the solid liquid interface. In this work, the interface instability is analyzed to explain the microstructure evolutions in terms of undercooling and characteristic lengths of solute diffusion and capillarity effect. (C) 2012 Elsevier Ltd. All rights reserved.