Initiation and propagation of small fatigue crack in beta titanium alloy observed through synchrotron radiation multiscale computed tomography

Xue, Gaoge; Nakamura, Takashi; Fujimura, Nao; Takahashi, Kosuke; Oguma, Hiroyuki; Takeuchi, Akihisa; Uesugi, Masayuki; Uesugi, Kentaro

doi:10.1016/j.engfracmech.2022.108308

Cited by 16 publications

(6 citation statements)

References 43 publications

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“…Liu et al used nano‐CT to investigate the three‐dimensional microstructures of the fine granular area in high strength steel 20 . Additionally, we successfully observed the mutual interaction between a small surface crack with the local microstructure by nano‐CT in a beta titanium alloy Ti‐22V‐4Al 21 . Therefore, it is expected that clearer images of small internal cracks than those of micro‐CT with the surrounding microstructure could be obtained.…”

Section: Introductionmentioning

confidence: 68%

“…20 Additionally, we successfully observed the mutual interaction between a small surface crack with the local microstructure by nano-CT in a beta titanium alloy Ti-22V-4Al. 21 Therefore, it is expected that clearer images of small internal cracks than those of micro-CT with the surrounding microstructure could be obtained. In this work, the difference between the opening behavior of small internal cracks and that of surface cracks was compared, and the possible reasons for the slow growth of internal cracks were discussed.…”

Section: Introductionmentioning

confidence: 99%

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Detection of small internal fatigue cracks in Ti‐6Al‐4V via synchrotron radiation nanocomputed tomography

Xue

Tomoda

Nakamura

et al. 2022

Fatigue Fract Eng Mat Struct

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Two types of synchrotron radiation computed tomography (SR‐CT)—projection CT (micro‐CT) and phase‐contrast imaging CT (nano‐CT)—were used to observe internal fatigue cracks in (α + β) Ti‐6Al‐4V alloy. Micro‐CT detected cracks in the specimen at ~1 μm spatial resolution, and the nano‐CT provided magnified images at ~200 nm spatial resolution. The crack initiation sites were clarified as the α‐phase for both the surface and internal cracks; however, their opening behaviors differed. A sharp crack tip was observed in the surface crack, and the crack tip opening displacement (CTOD) increased with an increase in the applied load. By contrast, a blunted crack tip, similar to that of a crack in a vacuum, was observed for the internal crack, and its CTOD remained almost constant regardless of the applied load. These phenomena are likely to explain the different behaviors of surface and internal cracks, particularly the slower growth rate of internal cracks, which leads to a longer fatigue life in the very high cycle fatigue regime.

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Section: Introductionmentioning

confidence: 68%

Section: Introductionmentioning

confidence: 99%

Detection of small internal fatigue cracks in Ti‐6Al‐4V via synchrotron radiation nanocomputed tomography

Xue

Tomoda

Nakamura

et al. 2022

Fatigue Fract Eng Mat Struct

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“…Some of the tomographic studies on metals have focused on topics related to quasi‐static defect evolution, [ 114–119 ] corrosion, [ 120 ] fatigue cracks, [ 115–117,119 ] diffusion [ 121 ] or hardness [ 76 ] for which the spatial and temporal resolution is usually not very high. Other studies deal with sintering of metals powders.…”

Section: Resultsmentioning

confidence: 99%

“…[ 126 ] Other groups focused on the analysis of crack development induced by pressure [ 115 ] or fatigue. [ 116 ] Recently, Wicke et al studied fatigue crack propagation in the commercial aluminum alloy EN‐AW 6082, [ 119 ] Xue et al in titanium [ 117 ] and Junet et al in TiAl6V4. [ 118 ] Tomography played a central role in all these works.…”

Section: Resultsmentioning

confidence: 99%

X‐ray Tomography and Tomoscopy on Metals: A Review

et al. 2023

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X‐ray tomography is a versatile tool in materials research and engineering since it allows for a non‐destructive and three‐dimensional mapping of the constituents of a heterogeneous material as long as they differ in their interactions with X‐rays. Recent developments of the technique have brought down the time needed for the acquisition of a single tomogram by many orders of magnitude compared to what was needed 25 years ago. Nowadays, up to 1000 full tomograms can be recorded in a second, which enables real‐time studies of changes in samples caused by reactions or by applied processing operations. The term tomoscopy has been coined for such sequences of 3D images. We review the application of X‐ray tomography and tomoscopy on metals and describe each step required and the associated challenges. A selection of representative investigations is presented with a focus on time‐resolved phenomena in metals and alloys ranging from mechanical deformation, solidification to metals processing processes such as welding and additive manufacturing. Finally likely future developments are discussed.

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“…For more efficient in-situ observations by SR X-ray CT, we developed a tabletop fatigue testing machine that allows the application of both static and cyclic loads on the beamline 37 , 38 . Our testing machine allows small increments of loading cycles to capture the gradual propagation of the internal damage by CT imaging.…”

Section: Methodsmentioning

confidence: 99%

X-ray nanoimaging of a transversely embedded carbon fiber in epoxy matrix under static and cyclic loads

Takahashi

Shoya

Matsuo

et al. 2022

Sci Rep

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The initial stage of fatigue failure has not been thoroughly clarified for carbon fiber reinforced plastics (CFRPs). Although the initiation of fatigue cracks has been regarded to be interfacial debonding between the carbon fiber and polymer matrix, their detection among numerous carbon fibers, whose diameter is only 7 µm, is extremely difficult. In this study, a single carbon fiber was transversely embedded in a dumbbell-shaped epoxy sample to focus on the interfacial debonding and was observed using synchrotron radiation (SR) X-ray computed tomography (CT). A tabletop fatigue testing machine driven by a piezoelectric actuator was developed to apply static and cyclic loads along the beamline. SR X-ray multiscale CT imaging was conducted by switching between an absorption-contrast projection method (micro-CT) and a phase-contrast imaging-type X-ray microscopic CT (nano-CT). The carbon fiber was entirely captured by micro-CT and then magnified at both ends on the free surfaces. Nano-CT clearly visualized the interfacial debonding under 30 MPa static tensile load and the implication of the coalescence of nano-voids along the interface under 50 MPa. Under cyclic loads, the interfacial debonding gradually progressed under a 8–40 MPa sinusoidal stress after 10,000 cycles, whereas it did not propagate under a stress below 30 MPa.

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Initiation and propagation of small fatigue crack in beta titanium alloy observed through synchrotron radiation multiscale computed tomography

Cited by 16 publications

References 43 publications

Detection of small internal fatigue cracks in Ti‐6Al‐4V via synchrotron radiation nanocomputed tomography

Detection of small internal fatigue cracks in Ti‐6Al‐4V via synchrotron radiation nanocomputed tomography

X‐ray Tomography and Tomoscopy on Metals: A Review

X-ray nanoimaging of a transversely embedded carbon fiber in epoxy matrix under static and cyclic loads

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