Journal ArticleDOI
Fatigue Crack Growth Behavior of PWA 1484 Single Crystal Superalloy at Elevated Temperatures
Jack Telesman,Louis J. Ghosn +1 more
TLDR
In this article, a study was done to determine the fatigue crack growth behavior of a PWA 1484 single-crystal nickel-base superalloy in a temperature range of 427 C to 871 C. The failure mode transitions were explained by invoking arguments based on environmental damage mechanisms.Abstract:
A study was done to determine the fatigue crack growth behavior of a PWA 1484 single-crystal nickel-base superalloy in a temperature range of 427 C to 871 C. Two distinctive failure modes were observed, which were a function of both temperature and frequency. At lower temperatures and higher frequencies crack growth occurred on the {l_brace}111{r_brace} octahedral slip planes at an oblique angle to the loading direction. Higher temperatures and decrease in frequencies favored a Mode I type failure process. The failure mode transitions were explained by invoking arguments based on environmental damage mechanisms. The fatigue crack growth rate data were analyzed using three different crack driving force parameters. The parameters investigated consisted of the Mode I stress intensity parameter corrected for the inclined crack trajectory, and two different octahedral Mode II parameters, which are based on the calculation of resolved shear stresses on the {l_brace}111{r_brace} slip systems. The Mode I {Delta}K parameter did a fair job in correlating the data but did not collapse it into a single narrow band. The two octahedral crack driving force parameters, {Delta}K{sub RSS} and a newly proposed {Delta}K{sub OCT}, collapsed all the data into a single narrow band. In addition to correlating the fatiguemore » crack growth rates, the two octahedral parameters also predicted the {l_brace}111{r_brace} planes on which the crack growth took place.« lessread more
Citations
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Journal ArticleDOI
Crack initiation mechanisms during very high cycle fatigue of Ni-based single crystal superalloys at high temperature
Alice Cervellon,Samuel Hémery,Philipp Kürnsteiner,Baptiste Gault,Baptiste Gault,Paraskevas Kontis,Jonathan Cormier +6 more
TL;DR: In this paper, a rough zone has been identified around the crack initiation site on the fracture surface and a crack initiation mechanism based on these observations and on the stress intensity parameter determined around the rough zone, which has been demonstrated to be a constant threshold dependent on the material.
Journal ArticleDOI
Ultrasonic fatigue of a single crystal Ni-base superalloy at 1000 °C
TL;DR: An ultrasonic fatigue testing system capable of operating at temperatures up to 1000°C has been developed and utilized to study the fatigue behavior of a single crystal superalloy (PWA 1484) at a temperature of 1000 ÂC and loading frequency of approximately 20 Â kHz as mentioned in this paper.
Journal ArticleDOI
Fatigue behaviour and lifing of two single crystal superalloys
D. W. Maclachlan,D.M. Knowles +1 more
TL;DR: In this article, a model has been developed to predict the high temperature cyclic life of single crystal superalloys RR2000 and CMSX-4 under conditions of creep and fatigue.
Journal ArticleDOI
Temperature effect on the low cycle fatigue behavior of a directionally solidified nickel-base superalloy
TL;DR: In this paper, the effect of temperature on low cycle fatigue behavior of a directionally solidified nickel-base superalloy has been investigated from 550 to 850 Â c. The fracture modes can be divided into three types: crystallographic plane facets fracture (shear fracture) at low temperature region ( 700 Â C), the dominant reason of the fracture mode transition with temperature is the deformation of the precipitated phase at different temperatures.
Journal ArticleDOI
Crack Paths in Single-crystal Ni-base Superalloys under Isothermal and Thermomechanical Fatigue
TL;DR: In this paper, the relative influences of the several crack growth parameters on the transition between Mode I opening and crystallographic shearing crack growth are graphically summarized, and the relative influence of these parameters on crack growth in Ni-base superalloys under isothermal and thermomechanical fatigue is analyzed.
References
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Journal ArticleDOI
The influence of temperature and cyclic frequency on the fatigue fracture of cube oriented nickel-base superalloy single crystals
G. R. Leverant,M. Gell +1 more
TL;DR: In this article, carbon-free single crystals of Mar-M200 were tested in pulsating tension, stress-controlled fatigue at temperatures and frequencies ranging from 1033 to 1255°K and 0.033 to 1058 Hz, respectively.
Journal ArticleDOI
Stress intensity factors for anisotropic compact-tension specimens with inclined cracks
Kwai S. Chan,Thomas A. Cruse +1 more
TL;DR: In this article, a boundary integral equation (BIE) technique has been applied for modeling compact-tension specimens of a Ni-based superalloy single crystal with an inclined crack, which allows explicit calculations of the K I and K II stress intensity factors for the inclined crack from the boundary condition data.
Journal ArticleDOI
The unusual near-threshold FCG behavior of a single crystal superalloy and the resolved shear stress as the crack driving force
Jack Telesman,Louis J. Ghosn +1 more
TL;DR: In this article, an investigation of the fatigue growth (FCG) behavior of PWA 1480 single crystal nickel base superalloy was conducted, where a region where the crack growth rate became essentially independent of the applied stress intensity was observed.
Journal ArticleDOI
Resolved shear stress intensity coefficient and fatigue crack growth in large crystals
Qi Chen,Hao-Wen Liu +1 more
TL;DR: In this article, the resolved shear stress intensity coefficient in a crack solid, RSSIC, is defined, and the coefficients for the slip systems at a crack tip are evaluated from the calculated stress intensity factors.
Book ChapterDOI
The Effect of Microstructure on the Fatigue Behavior of NI Base Superalloys
TL;DR: In this paper, the fatigue crack propagation (FCP) and low cycle fatigue (LCF) behavior of Ni base systems is reviewed. And it is shown that for typical Ni base alloys such as Waspaloy, Rene 95, In 718 and Astroloy the FCP rate decreases with increasing slip planarity.
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The unusual near-threshold FCG behavior of a single crystal superalloy and the resolved shear stress as the crack driving force
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