Scanning SQUID microscope differentiation of ferromagnetic steel phases

Shaw, T. J.; Chan, J.W.; Kang, Sungwon; McDermott, Robert; Morris, J.W.; Clarke, John

doi:10.1016/s1359-6454(00)00062-8

Cited by 7 publications

(9 citation statements)

References 17 publications

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“…The sample stage is placed on a brass table attached to an aligned x-y translation stage, which is operated by two stepper motors. A detailed description of this SQUID microscope can be also found in references [13] and [14]. This design makes it possible to scan a sample at room temperature by placing it in close proximity to the SQUID.…”

Section: Methodsmentioning

confidence: 99%

Detection of Fatigue Damage Prior Crack Initiation with Scanning SQUID Microscopy

Lee¹,

Morris²,

Lee³

et al. 2006

AIP Conference Proceedings

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ABSTRACT. The remanence fields of fatigued ferritic steel specimens were measured using a scanning microscope based on a high transition temperature Superconducting Quantum Interference Device (SQUID). The results show an overall increase of remanence until dislocation density saturates and an additional local remanence increase after saturation during cyclic loading. Because of the combined magnetic and spatial resolution of the SQUID microscope, these local changes of dislocation structures can be detected before a crack actually initiates, and identify the sites where crack nucleation will occur.

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Section: Methodsmentioning

confidence: 99%

Detection of Fatigue Damage Prior Crack Initiation with Scanning SQUID Microscopy

Lee¹,

Morris²,

Lee³

et al. 2006

AIP Conference Proceedings

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“…2 and described in detail in refs. [8] and [10]. A high-T c , thin film DC SQUID magnetometer is placed inside a vacuum enclosure and thermally coupled to a liquid nitrogen reservoir by a cold finger.…”

Section: Squid Microscope Apparatus and Measurementsmentioning

confidence: 99%

“…We have recently been investigating the applicability of a new technique, scanning SQUID microscopy, to the non-destructive evaluation of ferromagnetic materials such as structural steels [8][9][10][11]. This technique makes it possible to map the superficial magnetic field of a specimen with high precision and spatial resolution, revealing changes in the microstructural state of a material on a very fine scale.…”

Section: Introductionmentioning

confidence: 99%

“…This technique makes it possible to map the superficial magnetic field of a specimen with high precision and spatial resolution, revealing changes in the microstructural state of a material on a very fine scale. In prior work we have shown that SQUID microscopy can be used to distinguish the microstructural constituents of steel [10] and to identify gradients in plastic deformation (at least when these have associated gradients in the dislocation density [11]). In the present work we extended this investigation to high-cycle fatigue.…”

Section: Introductionmentioning

confidence: 99%

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Detecting damage in steel with scanning SQUID microscopy

Lee¹,

Clatterbuck²,

Morris³

et al. 2002

AIP Conference Proceedings

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ABSTRACT.A "Holy Grail" of NDE research is a non-destructive method for measuring fatigue damage prior to crack initiation. High-Tc scanning SQUID microscopy may be a useful tool. Because of the exceptional magnetic sensitivity of this technique, fatigue damage can be detected well before microcrack initiation, and in the absence of other obvious microstructure or property changes. Given the spatial resolution of the technique, undamaged material can be located and used to set internal standards.

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“…5 In SQUID microscopy, a specimen is scanned in close proximity to the SQUID microscope to produce a two-dimensional ͑2D͒ magnetic field image. [6][7][8] In this way, the SQUID microscope can serve as a useful nondestructive evaluation ͑NDE͒ tool by precisely measuring the local magnetic field variation that can be related to the characteristics of ferromagnetic materials. Therefore, it is expected that the HAZ in the deformed stainless steel with an ␣Ј martensite phase can be visualized by SQUID microscopy through the difference in remanent magnetization.…”

mentioning

confidence: 99%

High-Tc superconducting quantum interference device observation of heat-affected zone in a spot-welded Fe–Cr–Ni system

Watanabe

Kang

Chan

et al. 2003

Applied Physics Letters

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A study was carried out to observe a heat-affected zone (HAZ) in a deformed Fe–Cr–Ni system containing α′ martensite using high-Tc superconducting quantum interference device (SQUID) microscopy. Microstructure and remanent magnetization images were studied by an optical microscope and a SQUID microscope, respectively. The HAZ, in which only the face-centered-cubic austenite phase exists, could be visualized by the SQUID microscope. It was also found that the SQUID images were consistent with the results from the microstructural analysis. It was concluded that a simple SQUID measurement may serve as an effective method for a nondestructive evaluation of ferromagnetic steel phases by correlating remanent magnetization images to microstructural characteristics.

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Scanning SQUID microscope differentiation of ferromagnetic steel phases

Cited by 7 publications

References 17 publications

Detection of Fatigue Damage Prior Crack Initiation with Scanning SQUID Microscopy

Detection of Fatigue Damage Prior Crack Initiation with Scanning SQUID Microscopy

Detecting damage in steel with scanning SQUID microscopy

High-Tc superconducting quantum interference device observation of heat-affected zone in a spot-welded Fe–Cr–Ni system

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