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High-Temperature Properties of Liquid-Phase-Sintered Α-Sic

Published

Author(s)

R P. Jensen, William E. Luecke, N P. Padture, Sheldon M. Wiederhorn

Abstract

We have characterized the high-temperature subcritical crack growth and oxidation resistance of a liquid-phase-sintered (LPS) SiC with 20% volume fraction yttrium aluminum garnet (YAG) second phase. Constant stress rate testing in air in the temperature range 1100 - 1300 C yielded a crack growth exponent, n = 38.9 9.9 and an activation energy, Qscg = (380 237) kJ/mol-1. Oxidation followed parabolic kinetics in the temperature range 1100 -1300 C with an activation energy, Qox = (246 33) kJ/mol-1. At 1350 C reaction between the growing oxide layer and the YAG second phase produced a low-melting eutectic, resulting in accelereated oxidation. Below 1100 C, oxidation rates were also anomalously high for reasons we do not understand. In the intermediate temperature range, both the oxidation and the subcritical crack growth resistance compare favorably with other silicon carbides.
Citation
Materials Science and Engineering A-Structural Materials Properties Microstructure and Processing
Volume
Chapter 282

Keywords

constant stress-rate testing, dynamic fatigue, oxidation, silicon carbide, slow crack growth

Citation

Jensen, R. , Luecke, W. , Padture, N. and Wiederhorn, S. (1999), High-Temperature Properties of Liquid-Phase-Sintered Α-Sic, Materials Science and Engineering A-Structural Materials Properties Microstructure and Processing, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=850315 (Accessed February 28, 2024)
Created November 1, 1999, Updated February 19, 2017