Astm stp 1392 2000

STP 1392

Mechanical, Thermal

and Environmental Testing

and Performance of

Ceramic Composites and

Components

Michael G. Jenkins, Edgar Lara-Curzio, and

Stephen T. Gonczy, editors

ASTM Stock Number: STP1392

ASTM

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Library of Congress Cataloging-in-Publication Data

Mechanical, thermal, and environmental testing and performance of ceramic composites and

components / Michael G. Jenkins, Edgar Lara-Curzio, and Stephen T. Gonczy, editors.

p. cm (STP; 1392)

"ASTM stock number: STP1392."

"Papers presented at the Symposium on Environmental, Mechanical, and Thermal Properties and

Performance of Continuous Fiber Ceramic Composite (CFCC) Materials and Components held in

Seattle, Washington on 18 May 1999"--Foreword.

Includes bibliographical references and indexes.

ISBN 0-8031-2872-X

1. Fiber-reinforced ceramics--Environmental testing. 2. Fiber-reinforced ceramics--Mechanical

properties. 3. Fiber-reinforced ceramics--Thermal properties. I. Jenkins, Michael G., 1958- II. Lara￾Curzio, Edgar, 1963- II1. Gonczy, Stephen T., 1947- IV. Symposium on Environmental, Mechanical,

and Thermal Properties and Performance of Continuous Fiber Ceramic Composite (CFCC) Materials

and Components (1999: Seattle, Wash.)

TA455.C43 M45 2000

620.1 '4~dc21 00-059405

Copyright 9 2000 AMERICAN SOCIETY FOR TESTING AND MATERIALS, West Conshohocken,

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Each paper published in this volume was evaluated by two peer reviewers and at least one editor.

The authors addressed all of the reviewers' comments to the satisfaction of both the technical

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To make technical information available as quickly as possible, the peer-reviewed papers in this

publication were prepared "camera-ready" as submitted by the authors.

The quality of the papers in this publication reflects not only the obvious efforts of the authors and

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on behalf of ASTM.

Printed in Philadelphia, PA

September 2000

Foreword

This publication, Mechanical, Thermal and Environmental Testing and Performance of Ceramic

Composites and Components, contains papers presented at the Symposium on Environmental,

Mechanical, and Thermal Properties and Performance of Continuous Fiber Ceramic Composite

(CFCC) Materials and Components held in Seattle, Washington on 18 May 1999. ASTM Committee

C28 on Advanced Ceramics sponsored the symposium in cooperation with Committees E08 on

Fatigue and Fracture and D30 on Advanced Composites. Michael G. Jenkins, University of

Washington, Edgar Lara-Curzio, Oak Ridge National Laboratory, and Stephen T. Gonczy, Gateway

Materials Technology, presided as co-chairmen and are co-editors of the resulting publication.

Contents

Overview vii

PLENARY

Relationships of Test Methods and Standards Development to Emerging

and Retrofit CFCC Markets---T. a. BARNETT, G. C. OJARD, AND R. R. CAIRO

ROOM-TEMPERATURE TEST RESULTS/IV[ETHODS

Multiple-Laboratory Round-Robin Study of the Flexural, Shear, and Tensile Behavior

of a Two-Dimensionally Woven NicalonT~/Sylramic TM Ceramic Matrix

Composite--M. a. JENKINS, E. LARA-CURZIO, S. T. GONCZY, AND L. P. ZAWADA

Test Procedures for Determining the Delamination Toughness of Ceramic Matrix

Composites as a Function of Mode Ratio, Temperature, and Layup---

J. J. POLAHA AND B. D. DAVIDSON

Detailed Study of the Tensile Behavior of a Two-Dimensionally Woven NicalonTW

Sylramic TM Ceramic Matrix Composite---M. G. JENKINS AND L. P. ZAWADA

Testing Methodology for Measuring Transthiekness Tensile Strength for Ceramic

Matrix Composites--L. P. ZAWADA AND K. E. GOECKE

Flexural and Tensile Properties of a Two-Dimensional NicalonT~-Reinforced

SylramiO M S-200 Ceramic Matrix Composite--s. T. 6ONCZY AND M. G. JENKINS

15

31

48

62

86

TEST RESULTS]]V[ETHODS RELATED TO DESIGN IMPLICATIONS

Stress-Rupture, Overstressing, and a New Methodology to Assess the High￾Temperature Durability and Reliability of CFCCs--E. LARA-CURZIO

Use of Unload/Reload Methodologies to Investigate the Thermal Degradation of an

Alumina Fiber-Reinforced Ceramic Matrix Composite--c. • CAMPBELL AND

M. G. JENKINS

Fiber Test Development for Ceramic Composite Thermomechanical Properties--

J. A. DICARLO AND H. M. YUN

Effect of Fiber Waviness on the Tensile Response of 2D C(f)/SiC Ceramic Matrix

Composites--M. STEEN

107

118

134

148

Surface Finish and Notch Effect Model for Strength Predictions of Continuous Fiber

Ceramic Composites (CFCCs)--M. RAMULU, M. G. JENKINS, AND S. KUNAPORN

Notch-Sensitivity of a Woven Oxide/Oxide Ceramic Matrix Composite--R. JOHN,

D. J. BUCHANAN, AND L. P. ZAWADA

160

172

ENVIRONMENTAL EFFECTS AND CHARACTERIZATION

The Effects of Microstructural Damage on the Thermal Diffusivity of Continuous

Fiber-Reinforced Ceramic Matrix Composites---s. GRAHAM, D. L. MCDOWELL,

E. LARA-CURZIO, R. B. DINWIDDIE, AND H. WANG

Oxidation Behavior of Non-Oxide Ceramics in a High-Pressure, High-Temperature

Steam Euvironment--M. K. FERBER, H. T. LIN, AND J. KEISER

The Time-Dependent Deformation of Carbon Fiber-Reinforced Melt-Infiltrated Silicon

Carbide Ceramic Matrix Composites: Stress-Rupture and Stress-Relaxation

Behavior in Air at 1000~ LARA-CURZIO AND M. SINGH

The Relationship between Interphase Oxidation and Time-Dependent Failure

in SiCl/SiC m Composites--c. A. LEWINSOHN, C. H. HENAGER JR., E. P. SIMONEN,

C. F. WINDISCH JR., AND R. H. JONES

185

201

216

229

DAMAGE ACCUMULATION AND MATERIAL DEVELOPMENT

Characterization of Damage Accumulation in a Carbon Fiber-Reinforced Silicon

Carbide Ceramic Matrix Composite (C/SiC) Subjected to Mechanical

Loadings at Intermediate Temperature--M. VERRILLI, P. KANTZOS,

AND J. TELESMAN

Effect of Loading Mode on High-Temperature Tensile Deformation of a SiC/SiC

Composite--6. 0NAL

Effects of Temperature and Environment on the Mechanical Properties

of "Pyrrano-Hex TM Composites--M. DRISSI-HABTI, N. TAKEDA, K. NAKANO,

Y. KANNO, AND T. ISHIKAWA

Degradation of Continuous Fiber Ceramic Matrix Composites under Constant

Load Conditions--M. c. HALBIG, D. N. BREWER, AND A. J. ECKEL

Damage Accumulation in 2-D Woven SiC/SiC Ceramic Matrix Composites--

G. N. MORSCHER, J. Z. GYEKENYESI, AND R. T. BHATT

Summary

Author Index

Subject Index

245

262

276

290

306

321

327

329

Overview

In the nearly decade and a half since its establishment in 1986, ASTM Committee C28 has pro￾vided a major forum for promoting standardized terminology, guides, classifications, practices, and

test methods for advanced (a.k.a. structural, fine, and technical) ceramics. In particular, since 1991

ASTM Subcommittee C28.07 on Ceramic Matrix ASTM Composites has actively and vigorously

introduced and promoted standards and activities nationally (for example, through other ASTM

committees, Military Handbook 17, ASME Boiler and Pressure Vessel Code, etc.) and internation￾ally (for example, through ISO) for advanced ceramic matrix composites, specifically continuous

fiber ceramic composites.

Continuing these efforts, this publication and the Symposium on Environmental, Mechanical, and

Thermal Properties and Performance of Continuous Fiber Ceramic Composite (CFCC) Materials

and Components which was held in Seattle, Washington, 18 May 1999 were sponsored by ASTM

Committee C28. Twenty-two papers were presented at the symposium and this publication contains

twenty-one peer-reviewed manuscripts on continuous fiber-reinforced advanced ceramic compos￾ites, related test methods (standards), materials characterization, and design applications.

The advancement of technology has often been limited by the availability of materials and under￾standing of their behavior. Reflecting this emphasis on materials, in the technology of today, the US

government has supported programs such as the Continuous Fiber Ceramic Composites (CFCCs),

High Speed Research, and Enabling Propulsion Materials Programs which target specific new mate￾rials such as CFCCs for a broad range of applications, from chemical processing, to stationary heat

engines, to power generation, to aerospace vehicles. Such applications require that still-emerging

materials such as CFCCs be refined, processed, characterized, and manufactured in sufficient vol￾ume for successful widespread use in aggressive thermal/mechanical/environmental operating con￾ditions. Concurrently, as the materials are refined, designers must have access to material properties

and performance databases in order to integrate the material systems into their advanced engineer￾ing concepts. Without extensive materials characterization, producers of materials cannot evaluate

relative process improvements nor can designers have confidence in the performance of the materi￾al for a particular application.

Developing and verifying appropriate test methods as well as generating design data and design

experience for advanced materials is expensive and time consuming. High-temperature ceramic

composites are more expensive to process than monolithic ceramics, not just because of the extra

cost of constituent materials but also because of labor-intensive fabrication steps. Equipment for

testing at elevated temperatures is highly specialized and expensive. Unique and novel test methods

must be developed to take into account thermal stresses, stress gradients, measurement capabilities,

gripping methods, environmental effects, statistical considerations, and limited material quantities.

It is therefore imperative that test methods be carefully developed, standardized, verified, and uti￾lized so that accurate and statistically significant data are generated and duplication of efforts can

be minimized in test programs. Similarly, design codes must be written to establish which informa￾tion on material properties and performance are required for particular applications as well as which

standard test methods are recommended to quantify this information.

The papers in this publication provide current results of research and development programs on

continuous fiber ceramic composites. The papers are divided into four major categories:

1. Room-Temperature Test Results/Methods

2. Test Results/Methods Related to Design Implications

3. Environmental Effects and Characterization

4. Damage Accumulation and Material Development

vii

viii CERAMIC COMPOSITES AND COMPONENTS

The sections addressing these categories contain papers on various types of continuous fiber

ceramic composites, including those with matrices synthesized by chemical vapor infiltration (CVI),

polymer impregnation and pyrolysis (PIP), melt infiltration (MI), or viscous glass infiltration. The

Room-Temperature Test Results/Methods section includes papers on results of a round-robin pro￾gram that used several full-consensus standards, influence of various test parameters on the tensile,

shear and flexural behavior, novel transthickness tensile strength method, and delamination "tough￾ness" and its effects. The section on Test Results/Methods Related to Design Implications includes

papers on stress rupture, stress-relaxation and overstressing effects on testing and design,

unload/reload tensile tests, fiber testing, fiber waviness, surface finish notch effects and notch sen￾sitivity. The papers in the Environmental Effects and Characterization section address the thermal

diffusivity changes due to microstructural damage, oxidation behavior in aggressive environments,

time dependent deformation, and the effects of interphase oxidation. In the section on Damage

Accumulation and Material Development, papers address damage accumulation during mechanical

loading, effect of loading mode, temperature and environmental degradation of a novel pre-com￾mercial material, degradation under constant load, and process development of a novel material sys￾tem.

With this symposium and the resulting special technical publication, ASTM has made another

stride forward in standardization activities by providing a wealth of information on continuous fiber

ceramic composites. This information will assist the research, processing, and design community in

better understanding the behavior, characterization and design nuances of these materials. This

information is also invaluable for standards and code development background as test methods con￾tinue to be introduced and verified for continuous fiber ceramic matrix composites.

Michael G. Jenkins

Department of Mechanical Engineering

University of Washington

Seattle, WA 98195-2600

Symposium co-chair and co-editor

Edgar Lara-Curzio

Mechanical Characterization and Analysis

Group

Oak Ridge National Laboratory

Oak Ridge, TN 37831-67064

Symposium co-chair and co-editor

Stephen T. Gonczy

Gateway Materials Technology

Mt. Prospect, IL 60056

Symposium co-chair and co-editor

Plenary

Terry R. Barnett, ~ Greg C. Ojard, 2 and Ronald R. Cairo 2

Relationships of Test Methods and Standards Development to Emerging and

Retrofit CFCC Markets

Reference: Barnett, T. R., Ojard, G. C., and Cairo, R. R. "Relationships of Test

Methods and Standards Development to Emerging and Retrofit CFCC Markets,"

Mechanical, Thermal and Environmental Testing and Performance of Ceramic

Composites and Components, ASTM STP 1392, M. G. Jenkins, E. Lara-Curzio, and S. T.

Gonczy, Eds., American Society for Testing and Materials, West Conshohocken, PA,

2000.

Abstract: The evolutionary path of ceramic matrix composites (CMCs) to viable

candidate materials for current engineering designs of today and tomorrow has been

littered with appropriate and inappropriate theoretical models, useful and useless test

methods, and hopeful and hopeless materials systems. As continuous fiber ceramic

composite (CFCC) material systems have been introduced, theoretical models and

practical test methods have been proposed (and adopted) to characterize their behavior.

Often these materials are targeted for specific applications intended to exploit the bulk

CFCC as well as its constituent properties.

The unique position and expertise of the author's employer, a private research

laboratory, have enabled an up-close and detailed perspective on not only CFCCs and

their characterization but also the targeted engineering applications. In this paper, a case

study will be discussed regarding characterization of a CFCC for a particular application;

a high temperature combustor liner in a gas turbine engine. The potential for

standardized methods will be reviewed.

Keywords: ceramic, composite, continuous fiber ceramic composite, CFCC, ceramic

matrix composite, ring burst, hoop testing

Background

The author's employer is a private research laboratory with a well-established

1Manager, Experimental Mechanics Section, Southern Research Institute, 757 Tom

Martin Drive, Birmingham, AL 35211.

2Materials engineer and st~actures engineer, respectively, Pratt and Whitney, PO Box

109600, West Palm Beach, FL 33410.

3

Copyright9 ASTM International www.astm.org

4 CERAMIC COMPOSITES AND COMPONENTS

test and measurement capability and is widely recognized as one of the top laboratories in

the country for high temperature evaluation of advanced materials [1,2]. This position

has enabled an up-close and detailed perspective on not only the ceramic matrix

composites and their characterization but also the targeted engineering applications. In

this paper, a case study will be discussed regarding hoop characterization of a CMC for a

high temperature combustor liner in a gas turbine engine. The potential for standardized

methods will be reviewed.

The pursuit of next generation supersonic transports to carry people around the

world at twice the speed of sound has fostered the development of technology and

materials to make the effort cost effective, reliable, and environmentally compatible. In

order to meet these goals, companies have focused on advanced materials such as

ceramic matrix composites [3,4]. CMCs have the potential to enable components to run

hotter to improve thermodynamic efficiency and reduce noise and emissions. Innovative

design and the judicious use of CMCs in hot section components of gas turbine engines

and creative interfacing with metallic components are key to their successful

implementation. The ability to run without surface cooling has made CMCs particularly

attractive for combustor applications.

Case Study

Background

Material development on efforts like NASA's Enabling Propulsion Materials

(EPM) program has shown that properties from flat panels fabricated out of a silicon

carbide fiber/silicon carbide matrix (SiC/SiC) CMC can meet the design requirements for

proposed combustor liners [3,4]. A key contributor to the success of fabrication was

agreement and utilization of standard test methods that allowed testing to be done at a

variety of independent test laboratories with results that were consistent from laboratory

to laboratory. Testing was done in tensile, compressive, shear and flexural modes along

with thermal property characterization on a variety of SiC/SiC CMCs.

Application of a CMC- Combustor Liners

A major concern with high-speed air transports is the addition of nitrogen oxides

(NOx) to the upper atmosphere [5]. To reduce NOx emissions, new combustor

configurations that improve thermodynamic efficiency are required - CMCs are viable

candidate materials for such designs (Figure 1). Specific design parameters for the

combustor require the material withstand temperatures up to 1200 ~ depending on the

engine cycle, and resist thermal gradients that produce bendinb in the axial direction and

tensile stresses in the circumferential (hoop) direction (if bodies of revolution).

BARNETT ET AL. ON EMERGING AND RETROFIT CFCC MARKETS 5

Not only does thermal loading induce mechanical stress but also a propensity for micro￾structural degradation in oxidation prone CMCs [3,4,6,7]; thus, application is extremely

challenging.

Application of Test Methodology - Hoop Tensile Evaluation

To assess the materials resistance to thermal stress induced by axial temperature

gradients in combustor liners, one of the necessary properties is the hoop tensile strength.

Data obtained from coupons of flat plates would be a starting point; however, it is

generally known that as complexity of parts increase, properties tend to decrease because

of the difficulty of replicating ideal processing conditions in curved or transitional

regions or in the vicinity of unique out-of-plane features [8]. Consequently, a test

methodology to characterize hoop properties is required.

Figure 1 - CMC combustor liner [3]

In order to establish baseline room temperature hoop tensile properties, the

hydrostatic ring test facility [9,10] shcY~vn in Figure 2 was used. The facility consists of a

pressure vessel, a pump, and the ancillary equipment for measuring press1~re and strain.

6 CERAMIC COMPOSITES AND COMPONENTS

~ f PRESSURE TRANSDUCER

TE]P SPACER RING- L]-r~ A.__j--,--INPUT HYBRAULIC PRESSURE

--] II //OIL CAVITY~ --7

BLADDER"/ OIL SEAL /\-BOTTOM COVER PLATE

O-RING J

SPACER BLOCKS

Figure 2 - Schematic of the room temperature hydrostatic ring test facility [9,10]

The pressure vessel is made in several pieces. The two cover plates are clamped

together with a circle of bolts. The ring specimen is mounted between the upper and

lower spacer rings. Spacer blocks, mounted between the spacer rings, maintain

approximately 0.127 mm of clearance to allow for free radial movement. Application of

pressure by hydraulic oil to a rubber bladder, which mates to the inner diameter (ID) of

the ring, causes expansion of the specimen. (Note the facility is not size-limited and can

accommodate rings ranging from ~1.6 cm to 76 cm ID by ~0.25 cm to 6.4 cm height.)

A string wrapped around the outside of the hoop and attached to spring-loaded

linear variable differential transformers (LVDTs) mounted on a rigid frame (Figure 3)

monitors the circumferential change in displacement with increasing pressure. The

change in circumference can be transformed into the outer diameter (OD) circumferential

strain. A pressure transducer is used to measure the pressure applied to the ring. The

tensile hoop stress can be calculated using mechanics of materials relations for thin

walled pressure vessels such that

r

a = p- (1)

t

where

p = internal pressure

r = inner radius, and

t = wall thickness of hoop

BARNETT ET AL. ON EMERGING AND RETROFIT CFCC MARKETS 7

L ~r 0! ACircumference LVDT #II

~= Circumference

Figure 3 - L VDT/string arrangement for measuring hoop strain [9,10]

An X-Y plotter, or a data acquisition system, records the response of the ring

under the applied pressure. The plot consists of internal pressure versus the deformation

signal from the string. The data reported are ultimate hoop tensile strength, hoop elastic

modulus, and hoop tensile strain-to-failure. Typical hoop stress-strain responses from

ceramic matrix composites evaluated in this facility are shown in Figure 4.

Since the design of the combustor liner entails use at temperatures up to 1200 ~

hoop properties are required at these temperatures also. To obtain these properties, the

elevated temperature hoop facility (Figure 5) was used [11].

As with the room temperature test, pressure is applied to a rubber bladder by

hydraulic oil. However, in this case, the bladder mates to the ID of water-cooled wedges

(18 total), which in turn mate to low thermal conductivity wedges, which then mate to the

ID of the test ring. The wedge arrangement is required to reduce the radial temperature

from 1200 ~ at the ring to approximately room temperature at the bladder to prevent the

bladder from melting. For this arrangement, it has been analytically and experimentally

shown on an aluminum ring that the variation in circumferential stress as a result of the

wedge loading is less than +_5 percent [12]. (Further analysis is currently being

conducted using finite elements to determine the pressure profile applied to the ID of the

ring in both polar and axial directions and the true peak hoop stress in the CMC test ring.)

The ancillary equipment for the elevated temperature test is essentially as that for

the room temperature test. Typical stress-strain responses at various temperatures from

EPM SiC/SiC ceramic matrix composites evaluated in this facility are given below

(Figure 6).

35
84

CERAMIC COMPOSITES AND COMPONENTS

40. 275.8

Fiber #1

Ring Size: 9.75 em ID x 10.19 em OD x 1.27 cm

~8 em OD x 1.27 cm

30

~ 25

,20
84

9 ~15

m

10.

241.3

206.9

172.4 ,~ f~

137.9 ~

r~

103.4 ~

69.0

34.5

0 0.0

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

Tensile Hoop Strain, mm/mm x le-03

Figure 4- Typical EPM SiC~SiC CMC circumferential stress-strain response

at room temperature

8

Low Conductivity../ ~~~ ~Wa we#age .~ ~ ~ter cooled wedge

"n~ I~ eater

~~/ r LVDT cores spring loaded !"

] / and free to move (no Bladder / / stretch in string)

Electrodes

Figure 5 - Schematic of the elevated temperature hydrostatic ring test [11,12]