Deformation Behaviour of TRIP Steel Monitored by In Situ Neutron Diffraction

2014 ◽  
Vol 939 ◽  
pp. 25-30
Author(s):  
Jozef Zrník ◽  
Ondrej Muránsky ◽  
Petr Sittner
Keyword(s):  
Neutron Diffraction ◽  
Trip Steel ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Tensile Deformation ◽  
Deformation Behaviour ◽  
Tensile Load ◽  
Ferrite Matrix ◽  
Granular Bainite

The paper presents results ofin-situneutron diffraction experiments aimed on monitoring the phase evolution and load distribution in transformation induced plasticity (TRIP) steel when subjected to tensile loading. Tensile deformation behaviour of two TRIP-assisted multiphase steel with slightly different microstructures resulted from different thermo-mechanical treatments applied was investigated byin-situneutron diffraction. The steel with lower retained austenite volume fraction (fγ=0.04) and higher volume fraction of needle-like bainite in the α-matrix exhibits higher yield stress (sample B, 600MPa) but considerably lower elongation in comparison to the steel with higher austenite volume fraction (fγ=0.08), granular bainite and ferrite matrix (sample A, 500 MPa). The neutron diffraction results showed that the applied tensile load is redistributed at the yielding point in a way that the retained austenite bears a significantly larger load than the α-matrix during the TRIP steel deformation. Steel sample with higher volume fraction of retained austenite and less strong ferrite matrix proved to be a better TRIP steel with respect to strength, ductility and the side effect of the strain induced austenite-martensite transformation. The transforming retained austenite in time of loading provides potential for higher ductility of experimental TRIP steel but at the same time acts as a reinforcement phase during the further plastic deformation.TRIP steel, austenite conditioning, austenite transformation, structure, retained austenite, tensile deformation, neutron diffraction, load partitioning, mechanical properties.

Deformation Behaviour of TRIP Steel Monitoring by in-Situ Neutron Diffraction

2011 ◽  
Vol 465 ◽  
pp. 390-394 ◽  
Author(s):  
Jozef Zrník ◽  
Ondrej Muránsky ◽  
Petr Šittner ◽  
E.C. Oliver
Keyword(s):  
Neutron Diffraction ◽  
Trip Steel ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Tensile Deformation ◽  
Deformation Behaviour ◽  
Tensile Load ◽  
Phase Evolution ◽  
In Situ Neutron Diffraction

The paper presents results of in-situ neutron diffraction experiments aimed on monitoring the phase evolution and load distribution in TRIP steel when subjected to tensile loading. Tensile deformation behaviour of TRIP steel with different initial microstructures showed that the applied tensile load is redistributed at the yield point and the harder retained austenite (Feγ) bears larger load then ferrite (Feα) matrix. After load partioning is finished, macroscopic yielding comes through simultaneous activity of the martensite transformation (in the austenite) and plastic deformation process in ferrite. The steel with higher volume fraction of retained austenite and less stronger ferrite appears to be a better TRIP steel having efficient structure for better plasticity purpose.

Impact of Microstructure Modification on Deformation Behaviour of Bulk TRIP Steel

2014 ◽  
Vol 782 ◽  
pp. 99-103
Author(s):  
Jozef Zrník ◽  
Ondrej Muránsky ◽  
Petr Šittner
Keyword(s):  
Trip Steel ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Tensile Deformation ◽  
Deformation Behaviour ◽  
Tensile Load ◽  
Phase Evolution ◽  
Microstructure Modification ◽  
Plastic Deformation Process

The paper presents results ofin-situneutron diffraction experiments aimed on monitoring the phase evolution and load distribution in TRIP steel when subjected to tensile loading. Tensile deformation behaviour of TRIP steel with different initial microstructures showed that the applied tensile load is redistributed at the yield point and the harder retained austenite (Feγ) bears larger load then ferrite (Feα) matrix. After load partioning is finished, macroscopic yielding comes through simultaneous activity of the martensite transformation (in the austenite) and plastic deformation process in ferrite. The steel with higher volume fraction of retained austenite and less stronger ferrite appears to be a better TRIP steel having efficient structure for better plasticity purpose.

In Situ Neutron Diffraction Analysis of Phase Transformation Kinetics in TRIP Steel

2005 ◽  
Vol 502 ◽  
pp. 339-344 ◽  
Author(s):  
Jozef Zrník ◽  
O. Muránsky ◽  
Petr Lukáš ◽  
Petr Šittner ◽  
Z. Nový
Keyword(s):  
Neutron Diffraction ◽  
Trip Steel ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Internal Stresses ◽  
Austenite Transformation ◽  
Austenite Stability ◽  
Retained Austenite Stability ◽  
In Situ Neutron Diffraction

The precise characterization of the multiphase microstructure of low alloyed TRIP steels is of great importance for the interpretation and optimisation of their mechanical properties. In-situ neutron diffraction experiment was employed for monitoring of conditioned austenite transformation to ferrite, and also for retained austenite stability evaluation during subsequent mechanical loading. The progress in austenite decomposition to ferrite is monitored at different transformation temperatures. The relevant information on the course of transformation is extracted from neutron diffraction spectra. The integrated intensities of austenite and ferrite neutron diffraction profiles over the time of transformation are then assumed as a measure of the volume fractions of both phases in dependence on transformation temperature. Useful information was also obtained on retained austenite stability in TRIP steel during mechanical testing. The in-situ neutron diffraction experiments were conducted at two different diffractometers to assess the reliability of neutron diffraction technique in monitoring the transformation of retained austenite during room temperature tensile test. In both experiments the neutron investigation was focused on the volume fraction quantification of retained austenite as well as on internal stresses rising in structure phases due to retained austenite transformation.

Thermomechanical Processing Controlling the Austenite Transformation in Si – Mn TRIP Steel

2007 ◽  
Vol 345-346 ◽  
pp. 41-44
Author(s):  
Jozef Zrník ◽  
Ondrej Muránsky ◽  
Ondrej Stejskal ◽  
Peter Horňak
Keyword(s):  
Neutron Diffraction ◽  
Trip Steel ◽  
Tensile Testing ◽  
Retained Austenite ◽  
Thermomechanical Processing ◽  
Deformation Behaviour ◽  
Transformation Process ◽  
Austenite Transformation ◽  
Neutron Diffraction Technique

The paper deals with the deformation and transformation behaviour of thermomechanically (TM) treated low alloyed Si-Mn TRIP steel. The aim of this work was to investigate the contribution of the factors governing the deformation and transformation process of conditioned austenite. Variation in strain and temperature parameters of TM treatment of TRIP steel samples resulted in formation of different complex microstructures. The deformation behaviour of TRIP specimens of different multiphase structures was tested in incremental neutron diffraction in situ tensile testing. It was proved that neutron diffraction technique is very convenient method for retained austenite (RA) transformation of the retained austenite with respect to monitoring of transformation quantification of retained austenite and rising internal stress in structural phases.

scholarly journals Investigating the Difference in Mechanical Stability of Retained Austenite in Bainitic and Martensitic High-Carbon Bearing Steels using in situ Neutron Diffraction and Crystal Plasticity Modeling

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 482 ◽  
Author(s):  
Rohit Voothaluru ◽  
Vikram Bedekar ◽  
Dunji Yu ◽  
Qingge Xie ◽  
Ke An ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Crystal Plasticity ◽  
Retained Austenite ◽  
Mechanical Stability ◽  
Volume Fraction ◽  
High Carbon ◽  
Martensitic Matrix ◽  
Bearing Steels ◽  
In Situ Neutron Diffraction

In situ neutron diffraction of the uniaxial tension test was used to study the effect of the surrounding matrix microstructure on the mechanical stability of retained austenite in high-carbon bearing steels. Comparing the samples with bainitic microstructures to those with martensitic ones, it was found that the retained austenite in a bainitic matrix starts transforming into martensite at a lower strain compared to that within a martensitic matrix. On the other hand, the rate of transformation of the austenite was found to be higher within a martensitic microstructure. Crystal plasticity modeling was used to analyze the transformation phenomenon in these two microstructures and determine the effect of the surrounding microstructure on elastic, plastic, and transformation components of the strain. The results showed that the predominant difference in the deformation accumulated was from the transformation strain and the critical transformation driving force within the two microstructures. The retained austenite was more stable for identical loading conditions in case of martensitic matrix compared to the bainitic one. It was also observed that the initial volume fraction of retained austenite within the bainitic matrix would alter the onset of transformation to martensite, but not the rate of transformation.

Microstructure and Mechanical Properties of Hot Rolled TRIP Steel Based on Dynamic Transformation of Undercooled Austenite

2010 ◽  
Vol 152-153 ◽  
pp. 1038-1043
Author(s):  
Yun Yang Yin ◽  
Fang Fang ◽  
Zhi Jin Fan
Keyword(s):  
Electron Microscopy ◽  
Trip Steel ◽  
Retained Austenite ◽  
Volume Fraction ◽  
High Volume ◽  
Ferrite Matrix ◽  
Total Elongation ◽  
Dynamic Transformation ◽  
Hot Rolled ◽  
Undercooled Austenite

The microstructure characteristics and tensile properties in a 0.2C-1.5Mn-1.0Al-0.50Si, high strength hot rolled TRIP steel obtained by a new processing based on dynamic transformation of undercooled austenite(DTUA) were investigated. The results show that the main feature of the new technology is that the ferrite was produced by the applied strain during DTUA. Characterization by means of optical and scanning electron microscopy, transmission electron microscopy and X-ray diffraction has shown that the microstructure of the investigated steel contained a ferrite matrix with fine grain size, bainite with small bainitic packets, and high volume fraction of retained austenite with a large number of granular retained austenite. Tensile testing indicates the steels produced by this processing have higher strength (790MPa) and total elongation (35%) as well as low yield ratio..

Microstructure-dependent deformation behaviour of a low γ′ volume fraction Ni-base superalloy studied by in-situ neutron diffraction

2020 ◽  
Vol 183 ◽  
pp. 182-195 ◽  
Author(s):  
Nitesh Raj Jaladurgam ◽  
Hongjia Li ◽  
Joe Kelleher ◽  
Christer Persson ◽  
Axel Steuwer ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Volume Fraction ◽  
Deformation Behaviour ◽  
In Situ Neutron Diffraction ◽  
Base Superalloy

Experimental study on tensile deformation process of graphitized high carbon steel sheet

2021 ◽  
Vol 4 ◽  
pp. 74-80
Author(s):  
Zhang Yong Jun ◽  
◽  
Li Xin Peng ◽  
Wang Jiu Hua ◽  
Han Jing Tao ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Carbon Steel ◽  
Steel Sheet ◽  
Tensile Deformation ◽  
High Carbon Steel ◽  
Ferrite Matrix ◽  
High Carbon ◽  
Graphite Inclusion ◽  
Carbon Steel Sheet

As the object for the study, graphitized high-carbon steel sheet with a carbon content of 0.66 % was used, the tensile test of this sheet using a universal testing (breaking) machine was performed; as well as in-situ observation of the microstructure in the process of tensile deformation of this sheet using in-situ technology of scanning electron microscopy (SEM) was made. The test results show that the main mechanical properties in different directions of tested graphitized high-carbon steel sheet are relatively the same, that is, for a tensile sample of different directions, the ratio of the yield strength σ0,2 to the tensile strength σв is approximately 0.73; the strain hardening index n is approximately 0.24; the plastic deformation coefficient r is approximately 0.83. This indicates that this sheet did not exhibit significant anisotropy. In the process of tensile, deformation of the specimen is mainly developed from local plastic deformation of the graphite inclusions to the total deformation in the deformation zone of the sample; with the increase of displacement, micro-gap between the graphite inclusion and ferrite grain along the direction of the axis of tensile gradually formed and propagated along the direction perpendicular to the axis of tensile; number of slip lines in the ferrite matrix gradually increased, and the distance between them gradually decreases; when the sample breaks, in the fracture large dimple with the core of graphite inclusion and small dimples in the ferrite appears. And the ferrite matrix near the fracture is covered with slip lines, this shows that the ferritic matrix underwent severe plastic deformation before breaking.

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