scholarly journals Revealing the Dynamic Transformation of Austenite to Bainite during Uniaxial Warm Compression through In-Situ Synchrotron X-ray Diffraction

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 467
Author(s):  
William Lemos Bevilaqua ◽  
Jérémy Epp ◽  
Heiner Meyer ◽  
Juan Dong ◽  
Hans Roelofs ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Thermomechanical Processing ◽  
High Energy ◽  
Isothermal Treatment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Post Process ◽  
Dynamic Transformation ◽  
Bainitic Microstructure

In this work, the microstructural evolution during the dynamic transformation of austenite to bainite was directly observed by in-situ high energy synchrotron X-ray diffraction measurements during warm uniaxial compression performed at the P07 beamline of PETRA III, DESY (Deutsches Elektronen-Synchrotron). Plastic deformation triggers the phase transformation, which is continuously stimulated by the introduction of dynamic dislocations into the austenite. This scenario accelerates the kinetics of bainite formation in comparison with conventional isothermal treatment. No mechanical stabilization of austenite was observed during dynamic transformation. Evidence of carbon partitioning between phases during plastic deformation was obtained. Further post-process investigations suggest that the bainitic microstructure developed during compression is oriented perpendicular to the loading direction. The findings open up new possibilities to design carbide-free bainitic microstructures directly via thermomechanical processing.

Effect of Thermomechanical Processing on the Microstructure and Retained Austenite Stability during In Situ Tensile Testing Using Synchrotron X-Ray Diffraction of NbMoAl TRIP Steel

2011 ◽  
Vol 172-174 ◽  
pp. 741-746 ◽  
Author(s):  
Elena V. Pereloma ◽  
Lai Chang Zhang ◽  
Klaus Dieter Liss ◽  
Ulf Garbe ◽  
Jonathan Almer ◽  
...  
Keyword(s):  
Tensile Testing ◽  
Retained Austenite ◽  
Thermomechanical Processing ◽  
Critical Role ◽  
High Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
The Stability

In this work we compare and contrast the stability of retained austenite during tensile testing of Nb-Mo-Al transformation-induced plasticity steel subjected to different thermomechanical processing schedules. The obtained microstructures were characterised using optical metallography, transmission electron microscopy and X-ray diffraction. The transformation of retained austenite to martensite under tensile loading was observed by in-situ high energy X-ray diffraction at 1ID / APS. It has been shown that the variations in the microstructure of the steel, such as volume fractions of present phases, their morphology and dimensions, play a critical role in the strain-induced transition of retained austenite to martensite.

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

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.

scholarly journals Dislocation densities in a low-carbon steel during martensite transformation determined by in situ high energy X-Ray diffraction

2021 ◽  
Vol 800 ◽  
pp. 140249
Author(s):  
Juan Macchi ◽  
Steve Gaudez ◽  
Guillaume Geandier ◽  
Julien Teixeira ◽  
Sabine Denis ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Martensite Transformation ◽  
Low Carbon Steel ◽  
High Energy ◽  
Low Carbon ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dislocation Densities

scholarly journals Thermal expansion of La-based BMG studied by in situ high-energy X-ray diffraction

2010 ◽  
Vol 504 ◽  
pp. S155-S158 ◽  
Author(s):  
J. Bednarcik ◽  
C. Curfs ◽  
M. Sikorski ◽  
H. Franz ◽  
J.Z. Jiang
Keyword(s):  
Thermal Expansion ◽  
High Energy ◽  
X Ray Diffraction ◽  
X Ray

Solid state synthesis of LiFePO4 studied by in situ high energy X-ray diffraction

2011 ◽  
Vol 21 (15) ◽  
pp. 5604 ◽  
Author(s):  
Zonghai Chen ◽  
Yang Ren ◽  
Yan Qin ◽  
Huiming Wu ◽  
Shengqian Ma ◽  
...  
Keyword(s):  
Solid State ◽  
High Energy ◽  
Solid State Synthesis ◽  
X Ray Diffraction ◽  
X Ray

A Study on the Growth of Cubic GaN Films Using an AlGaAs Buffer Layer Grown on GaAs (100) by Plasma-Assisted Molecular Beam Epitaxy

2000 ◽  
Vol 639 ◽  
Author(s):  
Ryuhei Kimura ◽  
Kiyoshi Takahashi ◽  
H. T. Grahn
Keyword(s):  
Molecular Beam Epitaxy ◽  
Buffer Layer ◽  
Molecular Beam ◽  
High Energy ◽  
Rf Plasma ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cubic Gan

ABSTRACTAn investigation of the growth mechanism for RF-plasma assisted molecular beam epitaxy of cubic GaN films using a nitrided AlGaAs buffer layer was carried out by in-situ reflection high energy electron diffraction (RHEED) and high resolution X-ray diffraction (HRXRD). It was found that hexagonal GaN nuclei grow on (1, 1, 1) facets during nitridation of the AlGaAs buffer layer, but a highly pure, cubic-phase GaN epilayer was grown on the nitrided AlGaAs buffer layer.

scholarly journals Revealing the mechanism of electric-field-induced phase transition in antiferroelectric NaNbO3 by in situ high-energy x-ray diffraction

2021 ◽  
Vol 118 (13) ◽  
pp. 132903
Author(s):  
Mao-Hua Zhang ◽  
Changhao Zhao ◽  
Lovro Fulanović ◽  
Jürgen Rödel ◽  
Nikola Novak ◽  
...  
Keyword(s):  
Phase Transition ◽  
Electric Field ◽  
High Energy ◽  
X Ray Diffraction ◽  
X Ray

Using In Situ High-Energy X-ray Diffraction to Quantify Electrode Behavior of Li-Ion Batteries from Extreme Fast Charging

2021 ◽  
Author(s):  
Partha P. Paul ◽  
Chuntian Cao ◽  
Vivek Thampy ◽  
Hans-Georg Steinrück ◽  
Tanvir R. Tanim ◽  
...  
Keyword(s):  
High Energy ◽  
Li Ion Batteries ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fast Charging ◽  
Li Ion
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