Processing of ZrC-Mo Cermets for High Temperature Applications, Part II: Pressureless Sintering and Mechanical Properties
Pressureless sintering of ZrC-Mo cermets was investigated in a He/H2 atmosphere and under vacuum. a large density increase was observed for specimens with >20 vol% Mo after heating at 2150°C for 60 min in a He/H2 atmosphere. the increase in density was attributed to the formation of Mo2C during heating and its subsequent eutectic reaction with Mo, which produced rounded ZrC grains in a Mo-Mo2C matrix. Sintering in vacuum did not produce the same increase in density, due to the lack of Mo2C formation and subsequent lack of liquid formation, which resulted in a microstructure with irregular ZrC grains with isolated areas of Mo. Mechanical properties testing showed a decrease in Young's modulus with increasing Mo content that was consistent with the models presented. Flexure strength of ZrC-Mo cermets sintered in He/H2 atmosphere materials increased with increasing Mo content from 320 MPa at 20 vol% Mo to 410 MPa at 40 vol% Mo. Strength was predicted by adapting theories developed previously for WC-Co cermets.
S. E. Landwehr et al., "Processing of ZrC-Mo Cermets for High Temperature Applications, Part II: Pressureless Sintering and Mechanical Properties," Journal of the American Ceramic Society, Wiley-Blackwell, Jan 2008.
The definitive version is available at http://dx.doi.org/10.1111/j.1551-2916.2007.02231.x
Materials Science and Engineering
Keywords and Phrases
Young's Modulus; Cermets; Eutectic Reaction; Flexure Strength; Pressureless Sintering; Sintering
Article - Journal
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