This paper presents the preliminary results of our research on dynamic mechanical properties of silicon nitride based ceramics and ceramic composites at elevated temperatures. The temperature-dependent dynamic elastic modulus and internal damping of the cantilever beam samples were measured from room temperature up to 1100°C. The dynamic mechanical behavior is found to be rather stable up to 700°C, but damping peaks are found to occur at around 900°C, accompanied by a corresponding relaxation in elastic modulus for the tested samples. By simulating the thermal cycling environment of engines, the resulting changes in the dynamic mechanical properties of the samples are observed. The possible mechanisms affecting the dynamic mechanical properties of these ceramics and ceramic composites, with special emphasis on high-temperature behavior, are discussed.

Issue Section:
Gas Turbines: Ceramics
Topics:
Ceramic composites, Ceramics, Mechanical properties, Temperature, Damping, Elastic moduli, Cantilever beams, Engines, High temperature, Mechanical behavior, Relaxation (Physics), Silicon nitride ceramics
1.
Akimune
Y.
,
1990
, “
Impact Damage and Strength Degradation in a Silicon Carbide Reinforced Silicon Nitride Composite
,”
Journal of American Ceramics Society
, Vol.
73
(
10
), pp.
3019
–
3025
.
2.
Allor, R. L., Crosbie, C. M., Cartwright, E. L., and Govila, R. K., 1990, “Silicon Nitride Based Ceramic Composites,” Structural Composites: Design and Processing Technologies, ASM International, Materials Park, OH, pp. 555–641.
3.
Blevins, R. D., 1979, Formulas for Natural Frequency and Mode Shape, Van Nostrand Reinhold.
4.
Chawla, K. K., 1993, Ceramic Matrix Composites, Chapman & Hall.
5.
Crosbie, G. M., Nicholson, J. M., Predmesky, R. L., and Stiles, E. D., 1988, “Silicon Nitride Power Synthesis Program,” Proc. 25th Automotive Technology Development Contractors’ Coordination Meeting, Society of Automotive Engineers, Warrendale, PA, pp. 127–135.
6.
Findley, W. N., Lai, J. S., and Onaran, K., 1989, Creep and Relaxation of Nonlinear Viscoelastic Materials, Dover Publications, Inc.
7.
Gibson, R. F., Thirumalai, R., and Pant, R., 1991, “Development of and Apparatus to Measure Dynamic Modulus and Damping of Reinforcing Fibers at Elevated Temperature,” Proc. Society for Experimental Mechanics 1991 Spring Conference, Milwaukee, WI, June 9–12, pp. 860–869.
8.
Gibson
R. F.
,
1992
, “
Damping Characteristics of Composite Materials and Structures
,”
Journal of Materials Engineering and Performance
, Vol.
1
(
1
), pp.
11
–
20
.
9.
Grady
J. E.
, and
Lerch
B. A.
,
1992
, “
Effect of Heat Treatment on Stiffness and Damping of SiC/Ti-15-3
,”
Sample Quarterly—Society for the Advancement of Material and Processing Engineering
, Vol.
23
, No.
2
, pp.
11
–
16
.
10.
Hoffmann, M. J., and Petzow, G., 1993, “Microstructural Design of Si3N4 Based Ceramics,” Silicon Nitride Ceramics—Scientific and Technological Advances, Materials Research Society Symposium Proceedings, Vol. 287, pp. 3–14.
11.
Nashif, A. D., Jones, D. I. G., and Henderson, J. P., 1985, Vibration Damping, Wiley, New York.
12.
Suarez
S. A.
, and
Gibson
R. F.
,
1987
, “
Improved Impulse-Frequency Response Techniques for Measurement of Dynamic Mechanical Properties of Composite Materials
,”
Journal of Testing and Evaluation
, Vol.
15
(
2
), pp.
114
–
121
.
13.
Tien, T., 1993, “Silicon Nitride Ceramics—Alloy Design,” Silicon Nitride Ceramics—Scientific and Technological Advances, Materials Research Society Symposium Proceedings, Vol. 287, pp. 51–63.
14.
Warren, R., 1992, Ceramic-Matrix Composites, Chapman and Hall, New York.
15.
Woetting
G.
, and
Ziegler
G.
,
1986
, “
Powder Characteristics and Sintering Behavior of Si3N4 Powders
,”
Powder Metall. Intl.
, Vol.
18
(
1
), pp.
25
–
32
.
16.
Wren
G. G.
, and
Kinra
V. K.
,
1989
, “
On the Effect of an End-Mass on Beam Damping
,”
Experimental Mechanics
, Vol.
29
, pp.
336
–
341
.
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