Effect of elevated temperature and cyclic loading on properties and damage modes in ceramic composites

Technical Report · Mon Nov 01 04:00:00 EST 1993

OSTI ID:144837

Reifsnider, K L; Stinchcomb, W W; Oleksuk, L; Lee, S S ^[1]; Stinton, D P ^[2]

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1. Virginia Polytechnic Institute and State Univ., Blacksburg, VA (United States). Engineering Science and Mechanics Dept.
2. Oak Ridge National Lab., TN (United States)

This report discusses the results of a ongoing program of research concerned with the investigation of the effects of elevated temperature on the properties and performance of ceramic composites. The present report is concerned with just two aspects of the general program, the changes in properties and damage modes due to the effects of exposure of two ceramic composite systems to high temperature air and multiaxial loading. Two material systems and specimen configurations are discussed. Tubular specimens fabricated at the Oak Ridge National Laboratory using a SiC/SiC combination were tested quasi-statically at elevated temperatures. Changes in stiffness as a function of time and temperature were observed, and an SEM study revealed substantial differences in the microstructure associated with that exposure. Flat Nicalon/CAS-II coupons were fabricated by the Corning Glass Company, subjected to elevated temperature soaks for various periods of time and temperature, and then tested monotonically and under cyclic loading. Changes in damage and failure modes were observed that system, and a new surface damage mode on the fiber was discovered, possibly due to frictional sliding. The present report discusses the observations, interpretations, and some micromechanical modeling associated with these activities, and discusses the consequences of these temperature effects on future {open_quotes}designs{close_quotes} of material systems.

• Research Organization: Oak Ridge National Lab., TN (United States); Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Engineering Science and Mechanics
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 144837
• Report Number(s): ORNL/Sub--87-SA946/03; CCMS--93-18; ON: DE94008736
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COMPOSITE MATERIALS
COMPUTERIZED SIMULATION
DYNAMIC LOADS
FORECASTING
FRACTURE PROPERTIES
M CODES
MECHANICAL PROPERTIES
MECHANICAL TESTS
PLATES
SILICON CARBIDES
TEMPERATURE DEPENDENCE
TUBES