An evaluation of the fatigue crack propagation rate for powder metallurgical nickel-based superalloys using the DCPD method at elevated temperatures

Na, Seonghyeon; Yoon, Donghyun; Kim, J.H.; Kim, Hong‐Kyu; Kim, Dong-Hoon

doi:10.1016/j.ijfatigue.2017.04.003

Cited by 18 publications

(6 citation statements)

References 8 publications

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“…Errors in crack extensions during creep (under static loading at 500°) obtained between measured values and those predicted by calibrations predefined under fatigue loading were supposed to be due to changes in geometries of the specimen and crack tip caused by high temperature behaviour deformation [47]. Moreover, crack propagation is faster under elevated temperature, which was observed on powder metallurgical nickel-based superalloy by Na et al [158].…”

Section: High Temperature: Fatigue and Creep Loadingmentioning

confidence: 83%

“…The determination of calibration curves is found to significantly influence the accuracy of the method [56]. Several work have determined calibration curves and obtained linear [21,22,34,76,134,140,153,154] or non-linear [45,46,56,75,80,129,133,[155][156][157][158] relation between PDs and crack lengths. The linearity of calibration curves was regarded as an advantage of the PD technique over the other NTD methods [41,76].…”

Section: Introductionmentioning

confidence: 99%

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Potential difference methods for measuring crack growth: A review

Rouse

Hyde

2020

International Journal of Fatigue

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Non-destructive testing techniques are widely applied in industry for the evaluation of quantities of interest without inflicting additional damage accumulation. Crack detection and monitoring is a prime example of where non-destructive testing is valuable. Among the variety of non-destructive testing techniques, the direct current and alternating current potential difference methods, which are based on the principle that an electrical potential field around a conductive specimen is disturbed by the presence of geometric irregularities (or "features"), have received a great deal of attention in the literature. This is mainly due to the high levels of accuracy associated with these techniques and good estimations of crack initiation and propagation having been achieved.A critical review of the evolution and applications of potential difference methods is presented in this paper. Potential difference methods are capable of providing accurate and continuous measurements with simple installation and exclude the requirement of visual access under harsh service conditions. Alternating current potential difference methods require lower current input than direct current equivalents and hence provide higher sensitivity and offer better noise rejection but are vulnerable to capacitance effects and are more expensive. Calibration curves can be determined analytically, numerically, or by direct or analogue experimental techniques with each method offering strengths and limitations. Application of these should be determined in accordance with the specific scenario. The performance of electric probes (of voltage measurements and current injection) on topand side-face of C(T) and SEN(B) specimens are reviewed in detail as case examples. Specific guidance in normalising measurements and eliminating errors from thermoelectric effects can be implemented in order to improve the accuracy of PD methods. Abundant results have been obtained by applying PD methods in monitoring cracks geometries under aggressive conditions such as corrosion, high temperature, creep and cycled loading.

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Section: High Temperature: Fatigue and Creep Loadingmentioning

confidence: 83%

Section: Introductionmentioning

confidence: 99%

Potential difference methods for measuring crack growth: A review

Rouse

Hyde

2020

International Journal of Fatigue

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“…It has been proven that intergranular fracture is more conducive to FCP, greatly reducing the resistance to FCP. [42,43] With increasing ΔK, more dislocations are emitted from the crack tip, causing more hydrogen atoms to be carried. This results in more severe intergranular fracture on the fracture surface with the ΔK of 16 MPa Â m 0.5 compared to that with the ΔK of 12 MPa Â m 0.5 .…”

Section: Fracture Mechanisms Of Fcp Rate Specimens Tempered At 150 °Cmentioning

confidence: 99%

Factors Affecting the Cracking Resistances of a Spring Steel Tempered at Different Temperatures

Xia,

Zhang,

Wang

et al. 2024

steel research int.

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Cracking resistance is vital to the practical application of spring steels, which consists of fracture toughness (KIC) under the quasistatic loading condition and fatigue crack propagation (FCP) resistance under the cyclic loading condition. In the present study, the relation between the KIC/FCP resistance and microstructure of the 50CrMnSiVNb spring steel tempered at various temperatures is studied. In the results, it is shown that the dislocation density is the main factor influencing the KIC and FCP resistances, and the carbide size/quantity and morphology can also affect the KIC and FCP resistances. Thus, reducing the dislocation density is the most effective method to enhance the cracking resistance of the investigated steel. Moreover, decreasing the aspect ratio and obtaining a moderate size of tempered carbides are also beneficial to the cracking resistance. In addition, free hydrogen atoms can cause intergranular fracture on the fracture surface, worsening the FCP rate. To enhance the FCP resistance, smelting processes need to be improved to reduce the hydrogen content of the investigated steel.

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“…[1][2][3][4] Originally, the technique of powder metallurgy (P/M) was introduced for consolidating the superalloys to hinder them from being segregated, and also for fabricating the products with intricate shapes. [5] However, other problems such as gas porosity and undesired precipitation along previous particle boundaries (PPBs) were also found to occur in P/M superalloys. [6][7][8][9] There is a great interest in preparing the ultra-clean metal powders due to the extensive use of (P/M) superalloys in the production of high performance components in advanced gas engines.…”

Section: Introductionmentioning

confidence: 99%

Oxidation during the production of FGH4095 superalloy powders by electrode induction-melt inert gas atomization

Feng¹,

Xia²,

Chen³

2018

Chinese Phys. B

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Super-clean and super-spherical FGH4095 superalloy powder is produced by the ceramic-free electrode inductionmelt inert gas atomization (EIGA) technique. A continuous and steady-state liquid metal flow is achieved at high-frequency (350 kHz) alternating current and high electric power (100 kW). The superalloy is immersed in a high-frequency induction coil, and the liquid metal falling into a supersonic nozzle is atomized by an Ar gas of high kinetic gas energy. Numerical calculations are performed to optimize the structure parameters for the nozzle tip. The undesired oxidation reaction of alloying elements starts at 1000 • C with the reaction originating from the active sites on the powder surfaces, leading to the formation of oxides, Me x O y . The role of active sites and kinetic factors associated with the diffusion of oxygen present in the atomization gas streams are also examined. The observed results reveal that the oxidation process occurring at the surface of the produced powders gradually moves toward the core, and that there exists a clear interface between the product layer and the reactant. The present study lays a theoretical foundation for controlling the oxidation of nickel-based superalloy powders from the powder process step.

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An evaluation of the fatigue crack propagation rate for powder metallurgical nickel-based superalloys using the DCPD method at elevated temperatures

Cited by 18 publications

References 8 publications

Potential difference methods for measuring crack growth: A review

Potential difference methods for measuring crack growth: A review

Factors Affecting the Cracking Resistances of a Spring Steel Tempered at Different Temperatures

Oxidation during the production of FGH4095 superalloy powders by electrode induction-melt inert gas atomization

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