<i>In situ</i>observation of nucleation, fragmentation and microstructure evolution in Sn–Bi and Al–Cu alloys

Yasuda, Hideyuki; Yamamoto, Yasuhiko; Nakatsuka, Noriaki; Nagira, Tomoya; Yoshiya, Masato; Sugiyama, A.; Ohnaka, Itsuo; Umetani, Keiji; Uesugi, K.

doi:10.1179/136404608x361800

Cited by 49 publications

(19 citation statements)

References 11 publications

(4 reference statements)

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“…[9][10][11][12][13][14][15][16][17] The in situ observations of deformation at the grain scale in semi-solid Al-Cu alloys and carbon steels have been carried out using similar techniques. [18][19][20][21][22] Past research [18][19][20][21][22] showed that shear-induced dilation occurred by grain rearrangement including rotation and translation of solid particles in response to a force chain network at the low shear rate of 10 À3 to 10 À2 /s.…”

Section: Introductionmentioning

confidence: 99%

In Situ Observation of Deformation in Semi-solid Fe-C Alloys at High Shear Rate

Nagira

Morita

Yokota

et al. 2014

Metall Mater Trans A

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Synchrotron X-ray radiography at 125 frames per second was used to study deformation mechanisms in semi-solid Fe-C alloys at high solid fraction and shear strain rates of 10 À1 /s. An image correlation approach was also used to quantify the shear strain fields and study shearinduced dilation and the origin of shear cracking. It was shown that, at high solid fraction (90 to 93 pct solid), rearrangement including rotation and translation of solid particles became restricted and shear strain localized into narrow liquid-filled channels/fissures. Shear cracking was shown to originate from inadequate liquid flow into the expanding spaces between solid particles caused by shear-induced dilation. At lower solid fraction (~85 pct solid), solid particles rearranged with a significantly higher component of rotation leading to more shear-induced dilation and a wider shear band.

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Section: Introductionmentioning

confidence: 99%

In Situ Observation of Deformation in Semi-solid Fe-C Alloys at High Shear Rate

Nagira

Morita

Yokota

et al. 2014

Metall Mater Trans A

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“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] In the third generation synchrotron radiation facilities such as SPring-8, 21) hard X-rays with photon energy ranging from 10 to 100 keV can be used for the Xray imaging. The hard X-ray penetrates through bulk specimen of metallic materials.…”

Section: Introductionmentioning

confidence: 99%

Development of X-ray Imaging for Observing Solidification of Carbon Steels

et al. 2011

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Time-resolved X-ray imaging of dendritic solidification for pure Fe and carbon steels with sufficient spatial and time resolutions has been developed for the first time by overcoming essential problems in low contrast between solid and liquid phases and in high melting temperatures. Static observation showed that the solid/liquid interface in pure Fe specimen was determined by the absorption contrast at photon energy ranging from 16 to 30 keV. In addition, the phase contrast was also observed in the vicinity of the interface. Dynamic observation showed that cellular growth in pure Fe specimen was observed at a growth velocity up to 400 mm/s. Feasibility observation was also performed for two different carbon steels (0.0025 mass% C and 0.45 mass% C). Growing dendrites were observed in-situ at a growth velocity up to 500 mm/s. This study proves that the developed imaging enabled to observe solidification phenomena in-situ for various kinds of steels.KEY WORDS: in-situ observation; radiography; synchrotron radiation; dendrite.of carbon steels by X-ray imaging will be concluded. Based on the requirements, the paper explains an X-ray imaging developed by this study and demonstrates in-situ observation of solidification for pure Fe. Feasibility observations for carbon steels were briefly presented. Preparation of X-ray Imaging Requirement for Transmission X-ray ImagingImportant parameters for developing X-ray imaging using the absorption contrast are intensity of transmission X-ray through a specimen and contrast between different phases. One estimates the intensities through Fe-C alloys and pure Fe for building X-ray optics and for choosing dimension of specimen. In general, intensity of transmission X-ray, I, is expressed by (m/r) and r are the mass X-ray absorption coefficient and the mass density, respectively. The suffix, i, indicates constituent element species. r¯is average density and w i is mass fraction of the constituent element, i. The mass X-ray absorption coefficient, (m/r), which is a function of photon energy, is uniquely defined by the element.The linear X-ray absorption coefficient of Fe-C alloys is given byThe mass X-ray absorption coefficient of C is 0.044 m 2 /kg at 20 keV while that of Fe is 2.57 m 2 /kg at 20 keV. 27) Since the mass fraction of C is mostly less than 0.01 in conventional carbon steels, the mass X-ray absorption coefficient and the density of Fe dominantly determine the linear X-ray absorption coefficient of the Fe-C specimen.Conventional carbon steels contain Mn as well. The mass X-ray absorption coefficient of Mn is 2.25 m 2 /kg at 20 keV. 27) Since the partition coefficient of Mn in Fe matrix is approximately 0.75, difference in Mn concentration between solid and liquid phases is estimated to be 0.1-0.3 mass% for a specimen with average Mn concentration of 0.3-0.9 mass%. Change in the linear X-ray absorption coefficient is evaluated by the same procedure as for Fe-C system. The solute redistribution gives only 0.01-0.03% change in the linear X-ray absorption coefficient. The ch...

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“…[12][13][14][15][16][17][18][19][20][21] Recently a similar technique has been applied to in-situ observation of shear deformation in semi-solid Al-Cu and Fe-C alloys. [22][23][24] The time-resolved sequence of images showed impingement between solid particles and the translation and rotation of solid particles about their contacts in response to shear at the grain scale.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Shear Deformation Based on In-situ Observation of Deformation in Semi-solid Al–Cu Alloys and Water-particle Mixture

et al. 2013

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In-situ observation of deformation at the grain scale in semi-solid Al-Cu alloys has been carried out using synchrotron X-ray radiography. The deformed microstructure was characterized by the quantitative analysis of solid motion from the image sequences during shear in semi-solid Al-Cu alloys. The influence of solid particle shape on shear deformation was also examined by comparing with in-situ observation of deformation in water-polystyrene particle mixtures where the polystyrene particles are spherical with a diameter of 500 μm. In both semi-solid Al-Cu alloys and water-particle mixtures, solid particles located close to the shear plane developed an increasing component perpendicular to the shear plane, and a relatively high shear strain rate and decreased solid fraction was localized in a shear domain. The shear band width in semi-solid Al-Cu alloys (~10 mean particles diameter) was approximately two times wider than that formed in water-particle mixtures due to the difference in the solid particle shape.

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In situobservation of nucleation, fragmentation and microstructure evolution in Sn–Bi and Al–Cu alloys

Cited by 49 publications

References 11 publications

In Situ Observation of Deformation in Semi-solid Fe-C Alloys at High Shear Rate

In Situ Observation of Deformation in Semi-solid Fe-C Alloys at High Shear Rate

Development of X-ray Imaging for Observing Solidification of Carbon Steels

Characterization of Shear Deformation Based on In-situ Observation of Deformation in Semi-solid Al–Cu Alloys and Water-particle Mixture

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