Chapter 14. High Temperature Tensile Testing of Advanced Ceramics
- John B. Wachtman Jr.
Published Online: 26 MAR 2008
Copyright © 1989 The American Ceramic Society, Inc.
A Collection of Papers Presented at the 13th Annual Conference on Composites and Advanced Ceramic Materials, Part 1 of 2: Ceramic Engineering and Science Proceedings, Volume 10, Issue 7/8
How to Cite
Mejia, L. C. (1989) High Temperature Tensile Testing of Advanced Ceramics, in A Collection of Papers Presented at the 13th Annual Conference on Composites and Advanced Ceramic Materials, Part 1 of 2: Ceramic Engineering and Science Proceedings, Volume 10, Issue 7/8 (ed J. B. Wachtman), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470310557.ch14
- Published Online: 26 MAR 2008
- Published Print: 1 JAN 1989
Print ISBN: 9780470374863
Online ISBN: 9780470310557
- chemical vapor infiltration;
- tensile testing;
- gripping methods;
- servohydraulic system
Two methods of testing ceramics at high temperatures (to 1500°C and higher in air) are presented. One method uses a short furnace that accommodates a “warm” grip design in which portions of the grip at the specimen interface (via adapters) are allowed to reat temperatures in excess of 800°C (at or near the temperature limits of nickel-based super alloys). This warm grip approach minimizes thermal gradients within the gauge section of the specimen to acceptable levels. Design of the “warm” grip adapters will vary depending on specimen geometry and composition of the material (monolithic vs a composite such as a ceramic matrix). Method two describes both grips and specimen completely in the hot zone of a larger furnace. While promising to provide minimal thermal gradients within the specimen gauge section, this approach is plagued by many factors such as grip material selection, grip design, and specimen/grip chemical interactions. Advantages and disadvantages of both methods are discussed. Variations of the two approaches are also presented where specimen length (i.e., short) poses gripping and heating difficulties. Data on thermal gradients and bending strain induced on the specimen during the tensile test are also presented. Additionally, strain measurement and control of the tensile test utilize special “extensometers” that physically contact the specimen. Extensometer design to minimize contact force and still maintain measurement and control stability as well as selection of extensometer rod material provides additional testing difficulties in high temperature environments. Such factors are discussed as they affect the convenience and the precision of the tensile test.