Characterization of fatigue crack growth, damage mechanisms and damage evolution of the nickel-based superalloys MAR-M247 CC (HIP) and CM-247 LC under thermomechanical fatigue loading using in situ optical microscopy

Eckmann, Stefan; Schweizer, Christoph

doi:10.1016/j.ijfatigue.2017.01.015

Cited by 29 publications

(7 citation statements)

References 13 publications

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“…To get a better understanding of the damaging mechanisms under TMF‐loading, additional to the potential drop technique, far‐field optical microscopes were used 18 to track the advancing damage on corner crack (CC) specimens in situ. It was found that, while under OP loading mainly one crack seems to be evolving transgranularly, multiple cracks develop and evolve intergranularly and interdendritically under IP loading with hold times at maximum temperature.…”

Section: Introductionmentioning

confidence: 99%

Investigation of damage mechanisms and short fatigue crack growth during thermomechanical fatigue loading of the nickel‐based superalloy Inconel 100

Schackert

Schweizer

2022

Fatigue Fract Eng Mat Struct

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Growing demands on gas turbines, meaning lower consumption and higher efficiency, is accompanied by higher temperatures inside the turbine. Better lifetime prediction concepts for thermomechanical fatigue (TMF) loading of gas turbine components are needed to ensure safe operation. The influence of the TMF loading history—either in‐phase (IP) or out‐of‐phase (OP)—on crack initiation and short crack growth is studied for the cast nickel‐based super alloy IN100, which is commonly used as blade material. Therefore, smooth specimens are loaded at two different mechanical strain levels with, respectively, two phase relationships, using a temperature cycle T = 300–950°C and T = 300–850°C. The replica technique is used to detect cracks in the order of tens of micrometers. The differences in crack initiation and short crack growth are studied for the different loading conditions and the development of the crack length evolving from multiple short cracks is investigated.

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Section: Introductionmentioning

confidence: 99%

Investigation of damage mechanisms and short fatigue crack growth during thermomechanical fatigue loading of the nickel‐based superalloy Inconel 100

Schackert

Schweizer

2022

Fatigue Fract Eng Mat Struct

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“…The Ni base exhibits limited solubility to these trace elements. The trace elements interact with Ni in the base during welding, to form a low-melting-point eutectic phase, and segregate at the grain boundaries, leading to the precipitation of brittle carbides [18][19][20] during welding, resulting in clear hot cracks on the weld bead. This is also one of the main reasons that MAR-M247 is not applicable for repair welding.…”

Section: Introductionmentioning

confidence: 99%

Impact of electromagnetic stirring on the gas metal arc welding of an MAR-M247 superalloy

Yu-Chih

Lu²,

Chen

2021

Int J Adv Manuf Technol

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In this paper, the impact of electromagnetic stirring (EMS) on the gas metal arc welding (GATW) of an MAR-M247 superalloy was investigated. Results revealed that, without electromagnetic stirring, it was easy for carbides in the heat-affected zone (HAZ) of the weld bead to liquefy during welding, leading to weld bead cracks. Electromagnetic stirring re ned the grains in the HAZ and the weld bead, leading to grain strengthening and subsequently resulting in the effective improvement in the hardness of the weld bead. In addition, electromagnetic stirring signi cantly facilitated the formation of the weld bead by the removal of large inclusions which in turn effectively improved crack resistance at the joint. It also accelerated the oating up of gas holes thereby reducing the generation of gas hole defects.

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“…We did not find a specification of the dead time in literature although it is a critical parameter for PID controlled systems [7]. Because of the speed limitation, many authors use two different strain sensors within the same experiment: a mechanical extensometer measuring average strain for the PID controller at higher sampling rates, and an additional DIC system for other mechanical quantities like crack parameters measured in the spatially resolved strain field at lower frame rates [8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Real-Time GPU-Based Digital Image Correlation Sensor for Marker-Free Strain-Controlled Fatigue Testing

et al. 2019

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Digital image correlation (DIC) is a highly accurate image-based deformation measurement method achieving a repeatability in the range of σ = 10−5 relative to the field-of-view. The method is well accepted in material testing for non-contact strain measurement. However, the correlation makes it computationally slow on conventional, CPU-based computers. Recently, there have been DIC implementations based on graphics processing units (GPU) for strain-field evaluations with numerous templates per image at rather low image rates, but there are no real-time implementations for fast strain measurements with sampling rates above 1 kHz. In this article, a GPU-based 2D-DIC system is described achieving a strain sampling rate of 1.2 kHz with a latency of less than 2 milliseconds. In addition, the system uses the incidental, characteristic microstructure of the specimen surface for marker-free correlation, without need for any surface preparation—even on polished hourglass specimen. The system generates an elongation signal for standard PID-controllers of testing machines so that it directly replaces mechanical extensometers. Strain-controlled LCF measurements of steel, aluminum, and nickel-based superalloys at temperatures of up to 1000 °C are reported and the performance is compared to other path-dependent and path-independent DIC systems. According to our knowledge, this is one of the first GPU-based image processing systems for real-time closed-loop applications.

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Characterization of fatigue crack growth, damage mechanisms and damage evolution of the nickel-based superalloys MAR-M247 CC (HIP) and CM-247 LC under thermomechanical fatigue loading using in situ optical microscopy

Cited by 29 publications

References 13 publications

Investigation of damage mechanisms and short fatigue crack growth during thermomechanical fatigue loading of the nickel‐based superalloy Inconel 100

Investigation of damage mechanisms and short fatigue crack growth during thermomechanical fatigue loading of the nickel‐based superalloy Inconel 100

Impact of electromagnetic stirring on the gas metal arc welding of an MAR-M247 superalloy

Real-Time GPU-Based Digital Image Correlation Sensor for Marker-Free Strain-Controlled Fatigue Testing

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