In situ time-resolved X-ray diffraction of tobermorite formation process under hydrothermal condition: Influence of reactive al compound

Hydrothermal formation reaction of tobermorite in the autoclaved aerated concrete (AAC) process has been investigated by in situ X-ray diffraction. High-energy X-rays from a synchrotron radiation source in combination with a newly developed autoclave cell and a photon-counting pixel array detector were used. XRD measurements were conducted in a temperature range 100–190°C throughout 12 h of reaction time with a time interval of 4.25 min under a saturated steam pressure. To clarify the tobermorite formation mechanism in the AAC process, the effect of Al addition on the tobermorite formation reaction was studied. As intermediate phases, non-crystalline calcium silicate hydrate (C-S-H), hydroxylellestadite (HE), and katoite (KA) were clearly observed. Consequently, it was confirmed that there were two reaction pathways via C-S-H and KA in the tobermorite formation reaction of Al containing system. In addition, detailed information on the structural changes during the hydrothermal reaction was obtained.

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IN SITU STUDIES OF EPITAXIAL GROWTH BY SYNCHROTRON X-RAY DIFFRACTION

Surface Review and Letters ◽

10.1142/s0218625x06008256 ◽

2006 ◽

Vol 13 (02n03) ◽

pp. 155-166 ◽

Cited By ~ 1

Author(s):

WOLFGANG BRAUN ◽

KLAUS H. PLOOG

Keyword(s):

Ostwald Ripening ◽

Crystal Surface ◽

High Energy ◽

Molecular Beam Epitaxy Growth ◽

X Rays ◽

Surface Kinetics ◽

X Ray Diffraction ◽

X Ray ◽

Kinetics Of

X-rays are ideal to study the structure of crystals due to their weak interaction with matter and in most cases allow a quantitative analysis using kinematical theory. To study the incorporation of atoms during crystal growth and to analyze the kinetics on the crystal surface high primary beam intensities available at synchrotrons are required. Our studies of the molecular beam epitaxy growth of III–V semiconductors reveal that, despite their similarity in crystal structure, the surface kinetics of GaAs (001), InAs (001) and GaSb (001) differ strongly. GaAs shows an unexpectedly large coarsening exponent outside the predicted range of Ostwald ripening models during recovery. GaSb exhibits dramatically different surface morphology variations during growth and recovery. Overgrowth of GaAs by epitaxial MnAs demonstrates the ability of X-ray diffraction to follow an interface as it is buried during heteroepitaxy, which is not possible by reflection high-energy electron diffraction.

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Recrystallization of AA1050 Studied by 3DXRD

Materials Science Forum ◽

10.4028/www.scientific.net/msf.519-521.1569 ◽

2006 ◽

Vol 519-521 ◽

pp. 1569-1578

Author(s):

Dorte Juul Jensen

Keyword(s):

Single Crystals ◽

High Energy ◽

Nucleation And Growth ◽

X Rays ◽

X Ray Diffraction ◽

Orientation Relationships ◽

X Ray ◽

3 Dimensional ◽

Kinetics Of

By 3 dimensional X-ray diffraction (3DXRD) using high energy X-rays from synchrotron sources it is possible to study in-situ the nucleation and growth during recrystallization. In this paper it is described and discussed how 3DXRD can supplement EBSP measurements of nucleation and growth. Three types of studies are considered: i) orientation relationships between nuclei and parent deformed matrix, ii) recrystallization kinetics of individual bulk grains and iii) filming of growing grains in deformed single crystals.

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Metal Microstructures in Four Dimensions

X-Rays in Mechanical Engineering Applications ◽

10.1115/imece2004-62435 ◽

2004 ◽

Author(s):

S. F. Nielsen ◽

C. Gundlach ◽

E. M. Lauridsen ◽

R. V. Martins ◽

H. F. Poulsen ◽

...

Keyword(s):

Grain Growth ◽

Three Dimensional ◽

High Energy ◽

Third Generation ◽

Plastic Strains ◽

X Rays ◽

X Ray Diffraction ◽

X Ray ◽

Four Dimensions

By Three Dimensional X-ray Diffraction (3DXRD) microscopy it is possible to characterize microstructures non-destructively in 3 dimensions. The measurements are furthermore typically so fast that dynamics may be monitored in-situ, giving also the 4th dimension, namely the time. The 3DXRD technique is based on diffraction of high energy x-rays from third generation synchrotron sources. In the present paper the 3DXRD technique is described and it’s potentials are illustrated by examples relating to elastic and plastic strains, recovery, recrystallization and grain growth.

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Development of an in situ X-ray diffraction system for hydrothermal reactions and its application to autoclaved aerated concrete formation

Powder Diffraction ◽

10.1154/1.3583565 ◽

2011 ◽

Vol 26 (2) ◽

pp. 126-128 ◽

Cited By ~ 1

Author(s):

J. Kikuma ◽

M. Tsunashima ◽

T. Ishikawa ◽

S. Matsuno ◽

A. Ogawa ◽

...

Keyword(s):

Structural Changes ◽

Hydrothermal Reaction ◽

Photon Counting ◽

Phase Evolution ◽

High Energy ◽

Array Detector ◽

X Rays ◽

Autoclaved Aerated Concrete ◽

Aerated Concrete

An in situ time-resolved XRD system for hydrothermal reaction has been developed in order to investigate the phase evolution during autoclave process in autoclaved aerated concrete (AAC) formation. The system includes a novel autoclave cell for transmission XRD with thin beryllium windows, a two-dimensional photon-counting pixel array detector, and uses high energy X-rays from a synchrotron radiation source. The temperature and pressure inside the cell are extremely stable during hydrothermal reaction over the course of several hours. The system was utilized for the formation reaction of AAC. Phase evolution was clearly observed, including several intermediate phases, and detailed information on the structural changes during the hydrothermal reaction were obtained.

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In-Situ High-Energy X-ray Diffraction Study of Austenite Decomposition During Rapid Cooling and Isothermal Holding in Two HSLA Steels

Metallurgical and Materials Transactions A ◽

10.1007/s11661-021-06192-x ◽

2021 ◽

Vol 52 (5) ◽

pp. 1812-1825

Author(s):

Sen Lin ◽

Ulrika Borggren ◽

Andreas Stark ◽

Annika Borgenstam ◽

Wangzhong Mu ◽

...

Keyword(s):

Isothermal Holding ◽

Weight Percent ◽

High Energy ◽

Decomposition Kinetics ◽

Bainitic Transformation ◽

Austenite Decomposition ◽

X Ray Diffraction ◽

Rapid Cooling ◽

X Ray

AbstractIn-situ high-energy X-ray diffraction experiments with high temporal resolution during rapid cooling (280 °C s−1) and isothermal heat treatments (at 450 °C, 500 °C, and 550 °C for 30 minutes) were performed to study austenite decomposition in two commercial high-strength low-alloy steels. The rapid phase transformations occurring in these types of steels are investigated for the first time in-situ, aiding a detailed analysis of the austenite decomposition kinetics. For the low hardenability steel with main composition Fe-0.08C-1.7Mn-0.403Si-0.303Cr in weight percent, austenite decomposition to polygonal ferrite and bainite occurs already during the initial cooling. However, for the high hardenability steel with main composition Fe-0.08C-1.79Mn-0.182Si-0.757Cr-0.094Mo in weight percent, the austenite decomposition kinetics is retarded, chiefly by the Mo addition, and therefore mainly bainitic transformation occurs during isothermal holding; the bainitic transformation rate at the isothermal holding is clearly enhanced by lowered temperature from 550 °C to 500 °C and 450 °C. During prolonged isothermal holding, carbide formation leads to decreased austenite carbon content and promotes continued bainitic ferrite formation. Moreover, at prolonged isothermal holding at higher temperatures some degenerate pearlite form.

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