In this paper, scatter in crack growth for dwell time loadings in combination with overloads has been investigated. Multiple tests were performed for surface cracks at 550 °C in the commonly used high temperature material Inconel 718. The test specimens originate from two different batches which also provide for a discussion of how material properties affect the dwell time damage and overload impact. In combination with these tests, an investigation of the microstructure was also carried out, which shows how it influences the growth rate. The results from this study show that, in order to take overloads into consideration when analyzing spectrum loadings containing dwell times, one needs a substantial amount of material data available as the scatter seen from one batch to the other are of significant proportions.

References

References
1.
Larsen
,
J.
, and
Nicholas
,
T.
,
1983
, “
Load Sequence Crack Growth Transients in a Superalloy at Elevated Temperature
,”
14th National Symposium on Fracture Mechanics, Los Angeles, CA, June 30–July 2, Vol. II: Testing and Applications
, ASTM STP 791, pp.
II-536
II-552
.
2.
Nicholas
,
T.
, and
Weerasooriya
,
T.
,
1986
, “
Hold-Time Effects in Elevated Temperature Fatigue Crack Propagation
,” 17th National Symposium on Fracture Mechanics, ASTM STP 905, Albany, NY, Aug. 7–9, 1984, pp.
155
168
.
3.
Weerasooriya
,
T.
,
1987
, “
Effect of Frequency on Fatigue Crack Growth Rate of Inconel 718 at High Temperature
,” Air Force Wright Aeronautical Laboratories Report, Wright-Patterson Air Force Base, OH, Technical Report No. AFWAL-TR-87-4038.
4.
Andrieu
,
E.
,
Molins
,
R.
,
Ghonem
,
H.
, and
Pineau
,
A.
,
1992
, “
Intergranular Crack Tip Oxidation Mechanism in a Nickel-Based Superalloy
,”
Mater. Sci. Eng., A
,
154
(
1
), pp.
21
28
.
5.
Ghonem
,
H.
,
Nicholas
,
T.
, and
Pineau
,
A.
,
1993
, “
Elevated Temperature Fatigue Crack Growth in Alloy 718—Part I: Effects of Mechanical Variables
,”
Fatigue Fract. Eng. Mater. Struct.
,
16
(
5
), pp.
565
576
.
6.
Krupp
,
U.
,
2005
, “
Dynamic Embrittlement—Time-Dependent Quasi-Brittle Intergranular Fracture at High Temperatures
,”
Int. Mater. Rev.
,
50
(
2
), pp.
83
97
.
7.
Woodford
,
D. A.
,
2006
, “
Gas Phase Embrittlement and Time Dependent Cracking of Nickel Based Superalloys
,”
Energy Mater.
,
1
(
1
), pp.
59
79
.
8.
Ghonem
,
H.
, and
Zheng
,
D.
,
1992
, “
Depth of Intergranular Oxygen Diffusion During Environment-Dependent Fatigue Crack Growth in Alloy 718
,”
Mater. Sci. Eng., A
,
150
(
2
), pp.
151
160
.
9.
Molins
,
R.
,
Hochstetter
,
G.
,
Chassaigne
,
J. C.
, and
Andrieu
,
E.
,
1997
, “
Oxidation Effects on the Fatigue Crack Growth Behaviour of Alloy 718 at High Temperature
,”
Acta Mater.
,
45
(
2
), pp.
663
674
.
10.
Liu
,
X. B.
,
Ma
,
L. Z.
,
Chang
,
K. M.
, and
Barbero
,
E.
,
2005
, “
Fatigue Crack Propagation of Ni-Based Superalloys
,”
Acta Metall. Sin.
,
18
(
1
), pp.
55
64
.
11.
Gustafsson
,
D.
, and
Lundström
,
E.
,
2013
, “
High Temperature Fatigue Crack Growth Behaviour of Inconel 718 Under Hold Time and Overload Conditions
,”
Int. J. Fatigue
,
48
, pp.
178
186
.
12.
Ponnelle
,
S.
,
Brethes
,
B.
, and
Pineau
,
A.
,
2002
, “
High Temperature Fatigue Crack Growth Rate in Inconel 718: Dwell Effect Annihilations
,”
European Structural Integrity Society
, Elsevier, Vol.
29
, pp.
257
266
.
13.
Nicholas
,
T.
,
Haritos
,
G.
,
Hastie
,
R.
, Jr.
, and
Harms
,
K.
,
1991
, “
The Effect of Overloads on Sustained-Load Crack Growth in a Nickel-Base Superalloy: Part II—Experiments
,”
Theor. Appl. Fract. Mech.
,
16
(
1
), pp.
51
62
.
14.
Wanhill
,
R.
,
2002
, “
Significance of Dwell Cracking for IN718 Turbine Discs
,”
Int. J. Fatigue
,
24
(
5
), pp.
545
555
.
15.
ASTM
,
2008
, “
Standard Test Method for Measurement of Fatigue Crack Growth Rates
,”
ASTM International
,
West Conshohocken, PA
, ASTM Standard No. E647-08.
16.
Newman
,
J. C.
, Jr.
, and
Raju
,
I. S.
,
1984
, “
Stress-Intensity Factor Equations for Cracks in Three-Dimensional Finite Bodies Subjected to Tension and Bending Loads
,” NASA Langley Research Center, Hampton, VA, NASA Technical Memorandum No. 85793.
17.
Lundström
,
E.
,
Simonsson
,
K.
,
Gustafsson
,
D.
, and
Månsson
,
T.
,
2014
, “
A Load History Dependent Model for Fatigue Crack Propagation in Inconel 718 Under Hold Time Conditions
,”
Eng. Fract. Mech.
,
118
, pp.
17
30
.
18.
Saarimäki
,
J.
,
Moverare
,
J.
,
Eriksson
,
R.
, and
Johansson
,
S.
,
2014
, “
Influence of Overloads on Dwell Time Fatigue Crack Growth in Inconel 718
,”
Mater. Sci. Eng., A
,
612
, pp.
398
405
.
19.
Gutierrez-Urrutia
,
I.
,
Zaefferer
,
S.
, and
Raabe
,
D.
,
2009
, “
Electron Channeling Contrast Imaging of Twins and Dislocations in Twinning-Induced Plasticity Steels Under Controlled Diffraction Conditions in a Scanning Electron Microscope
,”
Scr. Mater.
,
61
(
7
), pp.
737
740
.
20.
Viskari
,
L.
,
Cao
,
Y.
,
Norell
,
M.
,
Sjöberg
,
G.
, and
Stiller
,
K.
,
2011
, “
Grain Boundary Microstructure and Fatigue Crack Growth in Allvac 718Plus Superalloy
,”
Mater. Sci. Eng., A
,
528
(
6
), pp.
2570
2580
.
21.
Lenets
,
Y. N.
,
2012
, “
Practical Aspects of Fatigue Crack Growth in Aero-GTE Applications
,”
ASME
Paper No. GT2012-68736.
22.
Storgärds
,
E.
, and
Simonsson
,
K.
,
2015
, “
Crack Length Evaluation for Cyclic and Sustained Loading at High Temperature Using Potential Drop
,”
Exp. Mech.
,
55
(
3
), pp.
559
568
.
You do not currently have access to this content.