Austenite-Ferrite Transformation in Non-Oriented Electrical Steels

The aim of the present work is to determine the austenite to ferrite transformation temperatures in a Si-Al non-oriented electrical steel. Critical transformation temperatures on heating and cooling are determined using an in-situ X-ray diffraction technique where the specimen is heated or cooled in a stepwise manner. The transformation temperatures are estimated from changes in the intensities of the (110)α and (111)γ peaks as a function of temperature. The time evolution of the microstructure resulting from isothermal heat treatments at temperatures between 800 and 1000 °C applied after cooling from 1050 °C is followed by quantitative metallography on samples quenched into water. The results show that, on cooling, formation of ferrite starts at about 950 °C and ends at 790 °C, indicating a strong effect of Si and Al on the austenite to ferrite and eutectoid transformations. These results suggest that the low tensile ductility exhibited by this material at temperatures near 1000 °C can be attributed to strain localization in strain-induced ferrite formed at temperatures as high as 1025 °C.

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Texture Evolution Under Fast Heating and Cooling Rates of Zirconium Alloys Studied In-Situ by Synchrotron X-Ray Diffraction

SSRN Electronic Journal ◽

10.2139/ssrn.3680386 ◽

2020 ◽

Author(s):

Chi-Toan Nguyen ◽

Alistair Garner ◽

Javier Romero ◽

Antoine Ambard ◽

Michael Preuss ◽

...

Keyword(s):

Texture Evolution ◽

Zirconium Alloys ◽

X Ray Diffraction ◽

Fast Heating ◽

Cooling Rates ◽

X Ray ◽

Heating And Cooling

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Phase Transitions in Gold Contacts to Gallium Arsenide

MRS Proceedings ◽

10.1557/proc-37-595 ◽

1984 ◽

Vol 37 ◽

Cited By ~ 2

Author(s):

Edward Beam ◽

D. D. L. Chung

Keyword(s):

Gallium Arsenide ◽

Phase Transitions ◽

Peritectic Transformation ◽

Complete Dissolution ◽

X Ray Diffraction ◽

X Ray ◽

Heating And Cooling ◽

Similar Phase ◽

Gold Contacts

AbstractX-ray diffraction was used in situ to study the phase transitions which occurred in 1500 Å Au/GaAs(100) upon heating and cooling. The reaction between Au and GaAs took the form Au + Ga → α Au-Ga. Upon heating, α Au-Ga completely dissolved in liquid Au-Ga. Upon subsequent cooling, β Au-Ga (or Au7Ga2) formed. In 1 atm of nitrogen, phase transitions were observed reversibly at 525 ± 25°C (due to the complete dissolution of α Au-Ga upon heating) and 415 ± 5°C (due to the peritectic transformation of β Au-Ga to α Au-Ga and liquid Au-Ga upon heating). In a vacuum of 425 μ (0.031 Kg/2m) similar phase transitions were observed at 425 ± 25°C and 387 ± 13°C, respectively.

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In situ x-ray diffraction study of graphitic carbon formed during heating and cooling of amorphous-C/Ni bilayers

Applied Physics Letters ◽

10.1063/1.3397985 ◽

2010 ◽

Vol 96 (15) ◽

pp. 153105 ◽

Cited By ~ 60

Author(s):

K. L. Saenger ◽

J. C. Tsang ◽

A. A. Bol ◽

J. O. Chu ◽

A. Grill ◽

...

Keyword(s):

Diffraction Study ◽

Graphitic Carbon ◽

X Ray Diffraction ◽

X Ray ◽

Heating And Cooling

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Sample chamber for synchrotron based in-situ X-ray diffraction experiments under electric fields and temperatures between 100 K and 1250 K

Journal of Synchrotron Radiation ◽

10.1107/s1600577520014344 ◽

2021 ◽

Vol 28 (1) ◽

pp. 158-168

Author(s):

Melanie Nentwich ◽

Tina Weigel ◽

Carsten Richter ◽

Hartmut Stöcker ◽

Erik Mehner ◽

...

Keyword(s):

Electric Fields ◽

Degrees Of Freedom ◽

X Ray Diffraction ◽

X Ray ◽

Heating And Cooling ◽

Hemispherical Dome ◽

Sample Chamber ◽

Overall Performance ◽

Scientific Questions

Many scientific questions require X-ray experiments conducted at varying temperatures, sometimes combined with the application of electric fields. Here, a customized sample chamber developed for beamlines P23 and P24 of PETRA III at DESY to suit these demands is presented. The chamber body consists mainly of standard vacuum parts housing the heater/cooler assembly supplying a temperature range of 100 K to 1250 K and an xyz manipulator holding an electric contact needle for electric measurements at both high voltage and low current. The chamber is closed by an exchangeable hemispherical dome offering all degrees of freedom for single-crystal experiments within one hemisphere of solid angle. The currently available dome materials (PC, PS, PEEK polymers) differ in their absorption and scattering characteristics, with PEEK providing the best overall performance. The article further describes heating and cooling capabilities, electric characteristics, and plans for future upgrades of the chamber. Examples of applications are discussed.

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Tensile Deformation of Ultrafine-Grained Fe-Mn-Al-Ni-C Alloy Studied by In Situ Synchrotron Radiation X-ray Diffraction

Crystals ◽

10.3390/cryst10121115 ◽

2020 ◽

Vol 10 (12) ◽

pp. 1115

Author(s):

Si Gao ◽

Takuma Yoshimura ◽

Wenqi Mao ◽

Yu Bai ◽

Wu Gong ◽

...

Keyword(s):

Synchrotron Radiation ◽

Tensile Deformation ◽

Tensile Ductility ◽

High Strength ◽

X Ray Diffraction ◽

Premature Failure ◽

X Ray ◽

Intermetallic Particles ◽

Ultrafine Grained

Intermetallic compounds are usually considered as deleterious phase in alloy designing and processing since their brittleness leads to poor ductility and premature failure during deformation of the alloys. However, several studies recently found that some alloys containing large amounts of NiAl-type intermetallic particles exhibited not only high strength but also good tensile ductility. To clarify the role of the intermetallic particles in the excellent tensile properties of such alloys, the tensile deformation behavior of an ultrafine-grained Fe-Mn-Al-Ni-C alloy containing austenite matrix and B2 intermetallic particles was investigated by using in situ synchrotron radiation X-ray diffraction in the present study. The elastic stress partitioning behavior of two constituent phases during tensile deformation were quantitively measured, and it was suggested that B2 particles played an important role in the high strength and large tensile ductility of the material.

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Mechanism of Solid-State Amorphization in the Fe-Si-Cu-Mg-O System

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.316.295 ◽

2021 ◽

Vol 316 ◽

pp. 295-299

Author(s):

Nikolai N. Nikul'chenkov ◽

Andrey A. Redikul'tsev ◽

Mikhail L. Lobanov

Keyword(s):

Solid Solution ◽

Solid State ◽

Amorphous State ◽

Continuous Annealing ◽

X Ray Diffraction ◽

Transformation Temperatures ◽

X Ray ◽

Heating And Cooling ◽

Cu Alloy ◽

State Amorphization

Solid-state amorphization process occurring at 600-1060 °C continuous annealing was observed by non-ambient x-ray diffraction on Fe-3%Si-0.5%Cu alloy surface with MgO as thermostable coating. The phenomenon was occurred at α→γ transformation temperatures (920-960 °C) in a layer consisting of Si solid solution in α-Fe and oxides (MgFe)2SiO4, (MgFe)O, SiO2. Amorphous state remained both during heating and cooling to 20 °C. Simulation for diffusion amorphization of Fe (Si) solid solution was proposed. Mg2Si complexes are reduced from oxides by hydrogen then transfer to solid solution and solid-state amorphization is occurred.

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Determination of equilibrium transformation temperatures Ae3 and Ae1 for low-carbon steels using the in situ high-temperature X-ray diffraction technique

Powder Diffraction ◽

10.1154/1.3308411 ◽

2010 ◽

Vol 25 (1) ◽

pp. 31-37

Author(s):

F. Equihua ◽

A. Salinas

Keyword(s):

High Temperature ◽

Carbon Steels ◽

Simulation Software ◽

Low Carbon ◽

X Ray Diffraction ◽

Transformation Temperatures ◽

X Ray ◽

Diffraction Patterns ◽

Integrated Intensities

This paper describes a method to determine the equilibrium transformation temperatures in low C steels using the in situ high-temperature X-ray diffraction technique. The samples were heated and then cooled from 1000 to 720 °C in a stepwise manner decreasing to −10 °C. Austenite and ferrite fractions were determined by a quantitative method using the integrated intensities of austenite (111)γ and ferrite (110)α peaks from X-ray diffraction patterns. The effect of the temperature on interplanar d spacings of (111) and (110) crystallographic planes was determined using 2θ maximum positions of the austenite (111)γ and ferrite (110)α peaks. The equilibrium transformation temperatures were determined to be Ae1=720 °C and Ae3=950 °C. The results are in excellent agreement with those obtained by dilatometric analysis and Thermo-Calc phase diagram simulation software. In addition, the results were supported by microstructural observations: the formation of thin ferrite films (5–10 μm) was observed at temperatures near to experimental Ae3.

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The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100071107 ◽

1973 ◽

Vol 31 ◽

pp. 132-133 ◽

Cited By ~ 1

Author(s):

R. E. Herfert

Keyword(s):

Surface Characterization ◽

Analytical Techniques ◽

X Ray Diffraction ◽

Depth Of Penetration ◽

X Ray ◽

The Past ◽

Transmission Electron ◽

Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

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