Study of the fatigue strength in the gigacycle regime of metallic alloys used in aeronautics and off

263 Pages·2017·31.4 MB·English

by  Perez Mora Ruben

Study of the fatigue strength in the gigacycle regime of
metallic alloys used in aeronautics and off-shore
industries
Perez Mora Ruben
To cite this version:
Perez Mora Ruben. Study of the fatigue strength in the gigacycle regime of metallic alloys used
in aeronautics and off-shore industries. Mechanics of materials [physics.class-ph]. Arts et Métiers
ParisTech, 2010. English. ￿NNT: 2010ENAM0027￿. ￿pastel-00671657￿
HAL Id: pastel-00671657
https://pastel.archives-ouvertes.fr/pastel-00671657
Submitted on 18 Feb 2012
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N°: 2009 ENAM XXXX

2010-ENAM-0027
Éccoollee ddooccttoorraallee nn°° 432 : SScciieenncceess eett MMééttiieerrss ddee ll’’iinnggéénniieeuurr

DDooccttoorraatt PPaarriissTTeecchh

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CIATEQ, A.C. ((CCentro de Tecnología AAvvaannzzaaddaa)

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SSppéécciiaalliittéé ““ Mécanique ”

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Rubén PEREZ MORA

le 8 septembre 2010

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Directeurs de thèse : TThhiieerrrryy PPAALLIINN-LLUUCC eett GGoonnzzaalloo MMaarriiaannoo DDOOMMIINNGGUUEEZZ AALLMMAARRAAZZ
Co-encadrement : Claude BATHIAS

Jury
M. Pedro GARNICA GONZALEZ,, DDrr..,, PPoossggrraaddoo eenn MMeettaalluurrggiiaa,, IInnssttiittuuttoo TTeeccnnoollóóggiiccoo ddee MMoorreelliiaa Président, Rapporteur T
M. Gérard MESMACQUE,, PPrrooffeesssseeuurr,, LLaabboorraattooiirree ddee MMééccaanniiqquuee ddee LLiillllee,, UUnniivv.. ddee LLiillllee Rapporteur
M. Claude BATHIAS, Professeur, LEME, UUnniivveerrssiittéé PPaarriiss XX Examinateur
H
M. Thierry PALIN-LUC,, PPrrooffeesssseeuurr,, LLAAMMEEFFIIPP,, AArrttss eett MMééttiieerrss PPaarriissTTeecchh BBoorrddeeaauuxx Examinateur
MM.. GGoonnzzaalloo MMaarriiaannoo DDOOMMIINNGGUUEEZZ AALLMMAARRAAZZ, Dr., Facultad de Ingeniería Mecánica, UMSNH Examinateur
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M. José MARTINEZ TRINIDAD, DDrr..,, EESSIIMMEE,, IInnssttiittuuttoo PPoolliittééccnniiccoo NNaacciioonnaall ddee MMééxxiiccoo Examinateur
M. Oscar César De SANTIAGO DURAN,, DDrr..,, CCIIAATTEEQQ AA..CC Examinateur
S

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AArrttss et Métiers ParisTech - Centre de Bordeaux
LAMEFIP

Acknowledgements

This work would not have had a good end without the strong support of several people and
institutions that I want to acknowledge in these few words.
I would first like to acknowledge my wife Elsa and my daughter Regina, who have been my
greatest motivation for being with me these past three years. I appreciate your love and your
patience throughout this time.
To my parents, my brothers and sisters, I want to say thanks for your support and your
strength because I was not able to be with you in several important moments or I was far
away during a lot of time.
I want to thank Mr. Thierry Palin-Luc for his invaluable supervision of this thesis, I
appreciate your teaching and your drive to succeed, you always encouraged me to have an
attitude of leadership and autonomy and I really appreciate that.
In the same way, I thank Mr. Gonzalo Dominguez for his supervision of this thesis, I am
grateful for having included me in this project since its inception. It was really a great
experience having worked on it.
I appreciate also the helpful support of the co-supervisors of this work, Mr. Claude Bathias in
France and Mr. Carlos Poblano in Mexico. I want to thank specially to Mr. Paul C. Paris, who
contributed in some parts of my work always with enthusiasm even when he was not my
supervisor.
I want to acknowledge Arts et Métiers ParisTech through its director Mr. Jean Paul Hautier,
to the Doctoral School of Arts et Métiers ParisTech through its director Mr. Gerard Coffignal
and to the LAMEFIP laboratory through its director Mr. Ivan Iordanoff; I acknowledge for
allowing me to develop this thesis work in their facilities using the multiple experiences of
their people.
I acknowledge CIATEQ, A.C., Centro de Tecnología Avanzada, for its financial support
during my doctoral stays in Mexico. I thank its director Mr. Victor Lizardi Nieto, the
coordinator of the PICYT postgrade program, Mr. Guillermo Frades Castedo and to the
manager of the Turbomachinery Department of CIATEQ, Mr. Fernando Aboites Dávila, for
accepting me in his workgroup as PhD student and more recently as engineer. Special thanks
to my immediate chief, Mr. Oscar De Santiago, for his encouragement for finishing the PhD.
I thank also to the French Program of Cooperation for Postgraduates (PCP France-Mexico)
and the Mexican Council of Science and Technology (Conacyt) for their financial support of
the exchange program.
I appreciate the confidence of the French company Turbomeca and the Spanish Vicinay
Cadenas with the LAMEFIP laboratory, to be considered for the study of their special
materials which allowed to have matter of study for this thesis. Specially thanks to Mr. José
Luis Arana from the Basque Country University, for his friendship and his strong support.
i
Acknowledgements
I want to recognize the help of the technicians in the French side, Christophe Lemaire,
Jonathan Merzeau, Jean-Marie Medard and Mathieu Lasserre, who helped me a lot when
several technical problems, not always easy, arrived.
To the staff of LAMEFIP in general, I want to say thanks for their friendly reception and for
their help in diverse aspects, such as the French language, because you were patient with me
during my learning.
Thanks to my colleagues at CIATEQ in Mexico who helped me in many technical and
administrative aspects; to Maritza Robles Gómez, Helen Zuñiga Osorio, Guadalupe López
Quintana, Conin Arcega Escobedo, José Saul Sosa, José Bernabé Hernández, Vicente Rangel
Fajardo, José Guadalupe Rico, Mariano Pérez Mora, Manuel Luna Tovar, Rómulo Hernández
Ferrer and Carlos Aguilar Barrón.
I want to thank the staff of CIATEQ in general, particularly the people of the Turbomachinery
Department, for your friendship, your encouragement and the nice working environment that
has made my stay enjoyable.

ii
Table of notations

a Crack length.
A Parameter of the Wöhler or Basquin curve.
α Exponent of the slope in the threshold of the da/dN curve following the
Paris-Hertzberg crack growth law.
b Burgers’ vector
B Parameter of the Wöhler or Basquin curve.
c Wave velocity
C Constant of the Paris law equation
C Parameter of calibration of the strain gauge
A
d Distance between two pits
da/dN Crack growth rate
ρ Density
E Elastic modulus
E Dynamic elastic modulus
d
e, ε Engineering or true strain
(cid:1)(cid:2) Strain rate
f Frequency
F Force
F Diameter of crack initiation specimen
Hz Hertz
Kt Stress concentration factor
k Stiffness
K Stress intensity
∆K, ∆K , ∆K Stress intensity range, threshold and effective
th eff
ω Frequency
M Modal mass
m Exponent of the Paris law equation
N Number of cycles to failure
f
ν Poisson’s ratio
P Static load
Pa, MPa Pascal, megapascal
p Probability of failure
S
R Stress ratio
iii
Table of Symbols
R Radius of pit
R Static strength
m
R Average roughness
a
S, S , S , S Stress, maximum, minimum and mean
max min m
s Standard deviation or seconds
s S Alternating stress
a, a
s s s Maximum, minimum and mean stress
max, min, m
U , A Displacement amplitude of the ultrasonic amplifier
0 0
T Temperature
V, V Tension voltage, root mean square
RMS
Y(a/w) Dimensionless correction function of Wu’s Equation
w Width of crack growth specimen
w Weight
√(cid:4)(cid:5)(cid:6)(cid:4) Square root of the area of a defect

iv
Table of Contents

Introduction ………………………………………………………………………………………………………………………….5

CHAPTER I: Literature review…..……………………………………………………………………………………..7
1. General concepts of fatigue...................................................................................................................................... 8
1.1. Fatigue crack initiation .................................................................................................................................. 10
1.2. Fatigue crack growth ...................................................................................................................................... 11
1.3. Regimes of fatigue ............................................................................................................................................ 13
1.4. Influence of mean stress on fatigue .......................................................................................................... 14
2. Gigacycle fatigue ........................................................................................................................................................ 16
2.1. Gigacycle fatigue interpretations ............................................................................................................... 18
2.2. Gigacycle fatigue testing machines ........................................................................................................... 20
2.3. Ultrasonic fatigue principles ........................................................................................................................ 23
2.4. Gigacycle fatigue of steel and aluminium alloys .................................................................................. 29
3. Effect of corrosion on fatigue ............................................................................................................................... 31
3.1. Corrosion fatigue crack initiation .............................................................................................................. 31
3.2. Corrosion crack initiation interpretations ............................................................................................. 37
3.3. Corrosion fatigue crack propagation ........................................................................................................ 38
3.4. Corrosion fatigue crack propagation interpretations ....................................................................... 40
4. Effects of defects on fatigue .................................................................................................................................. 44
References of Chapter I................................................................................................................................................. 51

CHAPTER II: Experimental conditions, materials and tests results …………..……………55
1. Gigacycle fatigue testing device .......................................................................................................................... 56
1.1. Crack initiation tests features ..................................................................................................................... 57
1.1.1 Specimen generalities............................................................................................................................... 57
1.1.2. Tension-compression tests (R=–1) .................................................................................................... 58
1.1.3. Tension-tension tests (R>0) ................................................................................................................. 58
1.1.4. Tests with imposed temperature ....................................................................................................... 59
1.1.5. Tests in sea water flow............................................................................................................................ 61
1.1.6. How to carry out crack initiation tests ............................................................................................. 61
1
Contents
1.2. Crack growth tests features ......................................................................................................................... 62
1.2.1. Specimen generalities.............................................................................................................................. 62
1.2.2. Crack growth observation ..................................................................................................................... 63
1.2.3. How to carry out crack growth tests ................................................................................................. 64
1.3. Machine components calculations ............................................................................................................ 67
1.3.1. Horns .............................................................................................................................................................. 67
1.3.2. Elongation bars .......................................................................................................................................... 69
1.4. Calibration ........................................................................................................................................................... 71
2. Fatigue tests on AS7G06 cast aluminium alloy ............................................................................................. 75
2.1. AS7G06 characteristics .................................................................................................................................. 75
2.2. Specimen geometry ......................................................................................................................................... 78
2.3. Temperature measurement of AS7G06 during tests ......................................................................... 80
2.4. AS7G06 fatigue results ................................................................................................................................... 82
2.4.1. Crack initiation tests at room temperature .................................................................................... 83
2.4.1.1. Tension-compression: R=-1 at room temperature ............................................................... 83
2.4.1.2. Tension-tension: R=0.01 at room temperature ..................................................................... 85
2.4.1.3. Tension-tension: R=0.5 at room temperature ........................................................................ 86
2.4.2. Crack initiation tests at 150 °C ............................................................................................................ 87
2.4.2.1. Tension-compression: R=-1 at 150 °C ........................................................................................ 87
2.4.2.2. Tension-tension: R=0.01 at 150 °C .............................................................................................. 89
2.4.3. Synthesis of the results on AS7G06 ................................................................................................... 90
3. Fatigue tests on R5 steel ........................................................................................................................................ 93
3.1. R5 steel characteristics .................................................................................................................................. 94
3.2. Specimen geometry ......................................................................................................................................... 97
3.3. Temperature measurement of R5 steel during testing .................................................................... 98
3.4. R5 steel fatigue results ................................................................................................................................... 101
3.4.1. Crack initiation tests without any corrosion .................................................................................. 101
3.4.1.1. Tension-compression: R=–1........................................................................................................ 101
3.4.1.2. Tension-tension: R=0.3 ................................................................................................................. 103
3.4.2. Effect of corrosion on fatigue crack initiation................................................................................ 104
3.4.2.1. Crack initiation with pre-corrosion: R=-1 ............................................................................. 104
3.4.2.2. Crack initiation with artificial sea water in situ: R=-1 ...................................................... 105
3.4.2.3. Surface roughness effect on fatigue strength under sea water flow .......................... 107
3.4.2.4. Corrosion with and without cyclic loading. .......................................................................... 108
3.4.3. Synthesis of crack initiation results ................................................................................................... 115
3.4.4. Crack growth tests results ..................................................................................................................... 117

References of chapter II............................................................................................................................................. 118

2
Contents
CHAPTER III: Fractography analysis and discussion ………………………………………………119
1. Analysis of AS7G06 cast aluminium alloy results ............................................................................. 120
1.1. Fractography of specimens tested at room temperature .................................................... 120
1.1.1. Tension-Compression (R=-1) at room temperature ................................................. 120
1.1.2. Tension-Tension (R=0.01) at room temperature ....................................................... 121
1.1.3. Tension-Tension (R=0.5) at room temperature ......................................................... 124
1.2. Fractography of specimens tested at 150 °C ......................................................................... 126
1.2.1. Tension-Compression: R=-1 at 150 °C ............................................................................ 126
1.2.2. Tension-Tension (R=0.01) at 150 °C ............................................................................... 129
1.3. Discussion ............................................................................................................................................ 131
2. Analysis of R5 steel results ........................................................................................................................ 134
2.1. Fractography of specimens tested without any corrosion ............................................. 134
2.1.1. Tension-Compression (R=–1)............................................................................................. 134
2.1.2. Tension-Tension (R=0.3) ...................................................................................................... 136
2.2. Fractography of specimens with corrosion ........................................................................... 138
2.2.1. Tension-Compression (R=-1) with pre-corrosion ..................................................... 139
2.2.2. Tension-Compression (R=-1) under sea water flow ................................................. 142
2.3. Discussion ............................................................................................................................................ 147
References of Chapter III...................................................................................................................................... 151

CHAPTER IV: Assessment of the fatigue crack initiation and propagation duration …..….153
1 Paris-Hertzberg crack growth law .................................................................................................................. 154
2 Application of the Paris-Hertzberg law to corrosion pits ..................................................................... 158
2.1 Assumptions ............................................................................................................................................... 159
2.2 Short crack initiation ............................................................................................................................... 160
3 Determination of the propagation stages duration ................................................................................. 165
3.1 From a to a (microstructural short crack growth regime) ................................................ 166
int 0
3.2 From a to a (physical short crack growth regime) .................................................................. 167
0 i
3.3 From a to a (long crack growth) .................................................................................................. 168
i final
3.4 Calculation of total propagation duration ...................................................................................... 170
4 Calculation for R5 steel with pre-corrosion................................................................................................ 172
5 Calculation for R5 steel with sea water corrosion ................................................................................... 174
6 Discussion ................................................................................................................................................................. 176
References of chapter IV ........................................................................................................................................... 178
3