Abstract
There is an international research effort to incorporate ceramic components into hot sections of heat engines. A major portion of this effort is directed towards the understanding and control of ceramic processing so that the strength of ceramics may be optimized. To date, the strength of sintered ceramics (e.g., SiC) is well below, by about two orders of magnitude, the theoretical strength [1,4]. This discrepancy is understood to be due to the presence of voids, inclusions, agglomerates, and anomalously large grains [4]. These defects, causing premature failure, are introduced or formed during the ceramic manufacturing process. Considerable work has already been done to remove these strength reducing material variations. This has resulted in a steady increase in the fracture strength of ceramics; however, the rate of this increase has slowed. Adding to the problem is the fact that the fracture strength of identically produced experimental samples varies as much as 35 percent [2]. As a result of the loss of momentum toward higher strengths, researchers are turning to ceramic- ceramic fiber composites. These composites show promise of increasing the fracture strength of ceramic materials even further. It is likely that the same material strength variations will be present, at least locally in the matrix, in ceramic composites.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
D.W. Richardson, Modern Ceramic Engineering: Properties, Processing and Use in Design, (Marcel Dekker, New York, 1982) Ch. 3.
S. Dutta, “Sinterability, Strength and Oxidation of Alpha Silicon Carbide Powders,” J. Mater. Sci., 19, 1307 (1984).
S. Dutta, “Strength Optimization of a-SiC By Improved Processing,” Structural Ceramics, NASA CP-2427, (NASA, Washington, D.C., 1986) pp. 89–98.
W.A. Sanders, and G.Y. Baaklini, “Correlation of Processing and Sintering Variables with the Strength and Radiography of Silicon Nitride,” Ceram. Eng. Sci. Proc., 7, 839 (1986).
S.J. Klima, and G.Y. Baaklini, “Ultrasonic Characterization of Structural Ceramics,” Analytical Ultrasonics in Materials Research and Testing, NASA CP-2383, (NASA, Washington, D.C., 1986) pp. 117–126.
G.Y. Baaklini, E.R. Generazio, and J.D. Kiser, “High Frequency Ultrasonic Characterization of Sintered SiC,” presented at the 11th Annual Conference on Composition and Advanced Ceramic Materials, Jan. 18–23, 1987, Cocoa Beach, FL.
E.R. Generazio, “The Role of the Reflection Coefficient in Precision Measurement of Ultrasonic Attenuation,” Mater. Eval. 43, 995 (1985).
D.R. Hull, H.E. Kautz, and A. Vary, “Measurement of Ultrasonic Velocity Using Phase-Slop and Cross-Correlation Methods,” Mater. Eval. 43, 1455 (1985).
W. Sachse, and Y.H. Pao, “On the Determination of Phase and Group Velocities of Dispersive Waves in Solids,” J. Appl. Phys., 39, 4320 (1978).
A.G. Evans, B.R. Tittman, L. Ahlberg, B.J. Khuri-Yakub, and G.S. King, “Ultrasonic Attenuation in Ceramics,” J. Appl. Phys. 49, 2669 (1978).
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 1988 Plenum Press, New York
About this chapter
Cite this chapter
Generazio, E.R., Roth, D.J., Baaklini, G.Y. (1988). Imaging Subtle Microstructural Variations in Ceramics with Precision Ultrasonic Velocity and Attenuation Measurements. In: Thompson, D.O., Chimenti, D.E. (eds) Review of Progress in Quantitative Nondestructive Evaluation. Springer, Boston, MA. https://doi.org/10.1007/978-1-4613-0979-6_43
Download citation
DOI: https://doi.org/10.1007/978-1-4613-0979-6_43
Publisher Name: Springer, Boston, MA
Print ISBN: 978-1-4612-8275-4
Online ISBN: 978-1-4613-0979-6
eBook Packages: Springer Book Archive