Mechanical Properties and Microstructure of Pressureless Sintered Duophase Sialon
Duophase (α′/β′) sialon is being developed for ceramic engine applications by using the Quickset™ injection molding process, followed by pressureless sintering and a thermal treatment. The sialon had an average four-point flexural strength of 670 MPa at room temperature and 490 MPa at 1370°C. It survived the flexural stress rupture test at 1300°C and 340 MPa for 190 hours. X-ray diffraction (XRD) and transmission electron microscopy (TEM) characterization showed that crystallization of the grain boundary phase improved the high temperature flexural strength of this sialon material. The creep behavior was also found to be affected by the crystallized grain boundary phases. The formation of a yttrium aluminum garnet (YAG) phase and elongated grains yielded better creep resistance. The correlation between mechanical properties and microstructure is discussed.
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- 2.Helms H.E., Haley P.J., Groseclose L.E., Hilpisch S.J. and Bell A.H. III., Advanced Turbine Technology Applications Project (ATTAP). in Proceeding of the Annual Automotive Technology Development Contractors’ Meeting, Society of Automotive Engineers, Inc. Dearborn, Michigan, October 22-25, 1990, pp. 89–103.Google Scholar
- 3.Prochazka S. and Rocco W.A., High Pressure Hot Pressing of Silicon Nitride Powders, in Nitrogen Ceramics, edited by Riley F.L., Noordhoff. Netherlands, 1981Google Scholar
- 5.Jack K.H., Crystal Chemistry of SiAlONs and Related Nitrogen Ceramics, in Nitrogen Ceramics. Edited by F.L. Riley, Noordhoff, Netherlands, 1977Google Scholar
- 7.Novich B.E., Lee R.-R., Franks G., and Ouellette D., Quickset™ Injection Molding of High Temperature Gas Turbine Engine Components. in Proceeding of the Annual Automotive Technology Development Contractors’ Meeting, Society of Automotive Engineers, Inc. Dearborn, Michigan, October 23-26, 1989, pp. 311–318.Google Scholar
- 8.Novich B.E., Lee R.-R., Franks G., Ouellette D., and Groseclose L.E., Ceramic Engine Components Fabricated by Using the Quickset Injection Molding Process. in 4th International Symposium on Ceramic Materials & Components for Engines., Goteborg, Sweden, June 10-12, 1991, published in this issue.Google Scholar
- 12.Lee R.-R., unpublished work.Google Scholar