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ACCELERATED AGING OF MATERIALS AND STRUCTURES: The Effects of Long-Term Elevated-Temperature Exposure
ACCELERATED AGING OF MATERIALS AND STRUCTURES
The Effects of Long-Term Elevated-Temperature Exposure
Committee on Evaluation of Long-Term Aging of Materials and Structures Using Accelerated Test Methods
National Materials Advisory Board
Commission on Engineering and Technical Systems
National Research Council
Publication NMAB-479
NATIONAL ACADEMY PRESS
Washington, D.C.
1996
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ACCELERATED AGING OF MATERIALS AND STRUCTURES: The Effects of Long-Term Elevated-Temperature Exposure
NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance.
This report has been reviewed by a group other than the authors according to procedures approved by a Report Review Committee consisting of members of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine.
The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. Upon the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Bruce M. Alberts is president of the National Academy of Sciences.
The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engineers. It is autonomous in its administration and in the selection of its members, sharing with the National Academy of Sciences the responsibility for advising the federal government. The National Academy of Engineering also sponsors engineering programs aimed at meeting national needs, encourages education and research, and recognizes the superior achievements of engineers. Dr. Harold Liebowitz is president of the National Academy of Engineering.
The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions in the examination of policy matters pertaining to the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, upon its own initiative, to identify issues of medical care, research, and education. Dr. Kenneth I. Shine is president of the Institute of Medicine.
The National Research Council was organized by the National Academy of Sciences in 1916 to associate the broad community of science and technology with the Academy's purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Bruce M. Alberts and Dr. Harold Liebowitz are chairman and vice chairman, respectively, of the National Research Council.
This study by the National Materials Advisory Board was conducted under Contract No. NASW-4938 with the National Aeronautics and Space Administration.
Available in limited supply from:
National Materials Advisory Board
2101 Constitution Avenue, NW
HA-262
Washington, D.C. 20418
202-334-3505
Copyright 1996 by the National Academy of Sciences . All rights reserved.
Printed in the United States of America.
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ACCELERATED AGING OF MATERIALS AND STRUCTURES: The Effects of Long-Term Elevated-Temperature Exposure
COMMITTEE ON EVALUATION OF LONG-TERM AGING OF MATERIALS AND STRUCTURES USING ACCELERATED TEST METHODS
EDGAR A. STARKE, JR. (Chair),
University of Virginia, Charlottesville
RICHARD H. CORNELIA,
DuPont, Wilmington, Delaware
LONGIN B. GRESZCZUK,
McDonnell Douglas Aerospace, Huntington Beach, California
LYNETTE M. KARABIN,
Alcoa Technical Center, Alcoa Center, Pennsylvania
JOHN J. LEWANDOWSKI,
Case Western Reserve University, Cleveland, Ohio
ASHOK SAXENA,
Georgia Institute of Technology, Atlanta
JAMES C. SEFERIS,
University of Washington, Seattle
RICHARD E. TRESSLER,
Pennsylvania State University, University Park
DOUGLAS D. WARD,
GE Aircraft Engines, Cincinnati, Ohio
National Materials Advisory Board Liaison Representative
JAMES E. MCGRATH,
Virginia Polytechnic Institute and State University, Blacksburg, Virginia
National Materials Advisory Board
THOMAS E. MUNNS, Senior Program Officer
AIDA C. NEEL, Senior Project Assistant
JOHN A. HUGHES, Research Associate
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ACCELERATED AGING OF MATERIALS AND STRUCTURES: The Effects of Long-Term Elevated-Temperature Exposure
NATIONAL MATERIALS ADVISORY BOARD
JAMES C. WILLIAMS (Chair),
GE Aircraft Engines, Cincinnati, Ohio
JAN D. ACHENBACH,
Northwestern University, Evanston, Illinois
BILL R. APPLETON,
Oak Ridge National Laboratory, Oak Ridge, Tennessee
ROBERT R. BEEBE,
Homestake Mining Company (Retired), Tucson Arizona
I. MELVIN BERNSTEIN,
Tufts University, Medford, Massachusetts
J. KEITH BRIMACOMBE,
University of British Columbia, Vancouver, Canada
JOHN V. BUSCH,
IBIS Associates, Inc., Wellesley, Massachusetts
HARRY E. COOK,
University of Illinois, Urbana
ROBERT EAGAN,
Sandia National Laboratories, Albuquerque, New Mexico
CAROLYN HANSSON,
Queen's University, Kingston, Ontario, Canada
KRISTINA M. JOHNSON,
University of Colorado, Boulder
LIONEL C. KIMERLING,
Massachusetts Institute of Technology, Cambridge
JAMES E. McGRATH,
Virginia Polytechnic Institute and State University, Blacksburg
RICHARD S. MULLER,
University of California, Berkeley
ELSA REICHMANIS,
AT&T Bell Laboratories, Murray Hill, New Jersey
EDGAR A. STARKE,
University of Virginia, Charlottesville
JOHN STRINGER,
Electric Power Research Institute, Palo Alto, California
KATHLEEN C. TAYLOR,
General Motors Corporation, Warren, Michigan
JAMES W. WAGNER,
The Johns Hopkins University, Baltimore, Maryland
JOSEPH G. WIRTH,
Raychem Corporation, Menlo Park, California
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ACCELERATED AGING OF MATERIALS AND STRUCTURES: The Effects of Long-Term Elevated-Temperature Exposure
Acknowledgments
The committee thanks the individuals who participated in the Workshop on Long-Term Aging of Materials and Structures. The information and ideas generated at the workshop were invaluable to the committee 's work. In particular, the effort that the invited speakers expended in preparing presentations for the conference is appreciated. Presentations were provided by Donald L. Grande, Boeing Commercial Aircraft Group; Michael D. Brunner, McDonnell Douglas; James C. Williams, GE Aircraft Engines; Han-Pin Kan, Northrop Aircraft Division; C.J. Peel, Defence Research Agency (UK); Mark D. Sensmeier, Virginia Polytechnic Institute and State University; Y.S. Matt Chou, Pacific Northwest Laboratory; Clive Bosnyak, Dow Chemical; Brian Wilshire, University College-Swansea (UK); John Stringer, Electric Power Research Institute; Rushad F. Eduljee, University of Delaware; Glenn C. Grimes, Lockheed Martin “Skunk Works”; Fahmy M. Haggag, Oak Ridge National Laboratory; Robert J. Bucci, Alcoa Technical Center; and Carlos Blohm, Lufthansa German Airlines.
The committee is particularly grateful to the National Aeronautics and Space Administration (NASA) liaison representatives, Charles E. Harris of NASA Langley Research Center and Michael Verilli of NASA Lewis Research Center for their participation in a number of committee discussions.
Finally, the committee gratefully acknowledges the support of Thomas E. Munns, National Materials Advisory Board Senior Program Officer, and Aida C. Neel, National Materials Advisory Board Senior Project Assistant.
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ACCELERATED AGING OF MATERIALS AND STRUCTURES: The Effects of Long-Term Elevated-Temperature Exposure
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ACCELERATED AGING OF MATERIALS AND STRUCTURES: The Effects of Long-Term Elevated-Temperature Exposure
Preface
A fundamental understanding of the physical phenomena associated with damage and failure must be developed to predict the response of a materials system to long-term exposure in a service environment. This can only be established by experimental materials characterization and development of the associated mathematical and computational models that describe the physical phenomena. While test methods and modeling codes are available to provide guidance on specific types of component design and test methodologies, these methods and models may require refinement and standardization.
The National Aeronautics and Space Administration requested the National Research Council's National Materials Advisory Board (NMAB) to identify issues related to the aging of advanced materials and suggest accelerated evaluation approaches and analytical methods to characterize the durability of future aircraft materials and structures throughout their service lives. An NMAB study committee was established to (1) provide an overview of long-term exposure effects on future high-performance aircraft structures and materials; (2) recommend improvements to analytical methods and approaches to accelerate laboratory testing and analytical techniques to characterize and predict material responses to likely aircraft operating environments; and (3) identify research needed to develop and verify the required testing, predictive analytical capabilities, and evaluation criteria.
The committee chose to examine the issues of long-term aging of materials and structures by examining candidates being considered for use on a future High-Speed Civil Transport as a case study.
The committee hosted a Workshop on Long-Term Aging of Materials and Structures, which was held at the National Academy of Sciences on August 10–12, 1994. Workshop attendees included representatives from industry, government, and academia. The results of this workshop served as an important resource for the preparation of the committee 's report.
Comments and suggestions that readers of this report wish to make can be sent via Internet electronic mail to nmab@nas.edu or by FAX to the National Materials Advisory Board (202) 334-3718.
Edgar A. Starke, Jr., Chair
Committee on Evaluation of Long-Term Aging of Materials and Structures Using Accelerated Test Methods
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ACCELERATED AGING OF MATERIALS AND STRUCTURES: The Effects of Long-Term Elevated-Temperature Exposure
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ACCELERATED AGING OF MATERIALS AND STRUCTURES: The Effects of Long-Term Elevated-Temperature Exposure
Contents
EXECUTIVE SUMMARY
1
1
INTRODUCTION
5
Aging of Materials and Structures,
5
Case Study: High-Speed Civil Transport,
6
2
AIRCRAFT OPERATING ENVIRONMENT
7
The Concorde Experience,
7
HSCT Conditions,
7
Summary and Recommendation,
9
3
CANDIDATE MATERIALS
11
Aluminum Alloys,
11
Titanium Alloys,
12
Superalloys,
13
Polymer-Matrix Composites,
14
Ceramic-Matrix Composites,
15
4
DEGRADATION MECHANISMS
17
Aluminum Alloys,
17
Titanium Alloys,
20
Superalloys,
22
Polymer-Matrix Composites,
23
Ceramic-Matrix Composites,
27
Recommendation,
28
5
ACCELERATED METHODS FOR CHARACTERIZATION OF AGING RESPONSE
29
Metallic Alloys,
29
Polymer-Matrix Composites,
36
Ceramic Systems,
40
Analysis of Structures,
41
Chapter Summary, Conclusions, and Recommendations,
42
REFERENCES
45
APPENDIX: BIOGRAPHICAL SKETCHES OF COMMITTEE MEMBERS
53
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ACCELERATED AGING OF MATERIALS AND STRUCTURES: The Effects of Long-Term Elevated-Temperature Exposure
Figures and Tables
FIGURES
2-1
External structural temperature during cruise for the Concorde,
7
2-2
Structural temperature for a typical flight of the Concorde,
8
2-3
Predicted equilibrium skin temperatures for a Mach 2.2 and Mach 2.4 HSCT,
8
2-4
Comparison of HSCT and subsonic engine duty cycle for comparable 5,000 nm flights,
9
3-1
Tensile yield strength at room temperature versus exposure temperature for several ingot metallurgy 2XXX alloys and X8019 after 1,000 hours exposure,
11
3-2
Fracture toughness versus tensile yield strength for (a) X8019 products and several ingot metallurgy alloys and (b) X8019 products and several moderately elevated-temperature ingot metallurgy 2XXX alloys,
12
3-3
(a) Fracture toughness and (b) elastic modulus of candidate titanium alloys as a function of normalized strength (strength/density),
13
4-1
Fracture toughness versus tensile yield strength for sheet from an experimental Al-Cu-Mg-Mn-Ag alloy in the T8-type temper and after 1,000 hours at 135 °C (275 °F),
18
4-2
Creep strain versus time for 2519-T87 products having varying grain sizes, tested at 175 °C (347 °F) under an initial stress of 20 ksi,
19
4-3
Effect of grain size on a variety of mechanical properties for nickel-based superalloys,
22
4-4
Schematic of transverse matrix cracks in a cross-plied composite laminate,
24
4-5
Normalized axial modulus of [0,902]s graphite/epoxy laminate as a function of transverse crack density,
24
4-6
Progression of oxidative degradation zone in a carbon/bismaleimide composite,
25
4-7
Schematic of composite laminate moisture profile and micrograph of surface-matrix cracking: (1) initial moisture load; (2) moisture profile after hygrothermal cycles,
25
4-8
Major types of corrosive attack and degradation as an approximate function of reciprocal temperature (Ptotal = Poxidant),
27
5-1
Relative creep strength of candidate alloys for the Concorde,
31
5-2
Deformation mechanism maps for 316 stainless steel after exposure for (a) 3 years and (b) 30 years,
32
5-3
Creep crack growth behavior of Cr-Mo and Cr-Mo-V base materials,
32
5-4
Comparison between creep crack growth and creep-fatigue crack growth data in terms of Ct,
33
5-5
Schematic showing use of the Arrhenius expression for describing a reaction or property degradation rate,
34
5-6
Room-temperature tensile yield strength as a function of exposure time at various temperatures for 2618-T651 extrusions,
34
5-7
Plot of ln (1/t) versus 1/T for 2618-T651 extrusions overaged to 50, 40, 30, and 20 ksi,
35
5-8
Stress for 0.1 percent creep strain as a function of time at various temperatures for 2618-T651 extrusions,
35
5-9
Plot of ln (1/t) versus 1/T for 2618-T651 extrusions overaged to 30 ksi, crept to 0.1 percent, 0.5 percent, or rupture,
36
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ACCELERATED AGING OF MATERIALS AND STRUCTURES: The Effects of Long-Term Elevated-Temperature Exposure
5-10
Variation of room-temperature flexural strength with exposure time at elevated temperatures,
39
5-11
Correlation of room-temperature strength after various exposure times and temperatures at 760 torr,
39
5-12
Damage progression of matrix cracking in a laminate versus number of cycles,
40
5-13
Recommended general approach to characterization of aging of materials and structures,
44
TABLES
5-1
Critical Degradation Mechanisms for Advanced Metallic Alloys,
30
5-2
Critical Deformation Mechanisms for Advanced Metallic Alloys,
31
5-3
Critical Degradation Mechanisms for Polymeric Composites,
38
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ACCELERATED AGING OF MATERIALS AND STRUCTURES: The Effects of Long-Term Elevated-Temperature Exposure
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