Deformation Behaviour of TRIP Steel Monitoring by 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.

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Deformation Behaviour of TRIP Steel Monitored by In Situ Neutron Diffraction

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.939.25 ◽

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.

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Impact of Microstructure Modification on Deformation Behaviour of Bulk TRIP Steel

Materials Science Forum ◽

10.4028/www.scientific.net/msf.782.99 ◽

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.

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

Materials Science Forum ◽

10.4028/www.scientific.net/msf.502.339 ◽

2005 ◽

Vol 502 ◽

pp. 339-344 ◽

Cited By ~ 7

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.

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OS0106 In-situ Neutron Diffraction Study on Tensile Deformation Behaviour of Mg-Zn-Y Alloy Containing of LPSO Phases

The Proceedings of the Materials and Mechanics Conference ◽

10.1299/jsmemm.2014._os0106-1_ ◽

2014 ◽

Vol 2014 (0) ◽

pp. _OS0106-1_-_OS0106-3_

Author(s):

Satoshi MOROOKA ◽

Gong WU ◽

Kazuya AIZAWA ◽

Osamu UMEZAWA ◽

Michiaki YAMASAKI ◽

...

Keyword(s):

Neutron Diffraction ◽

Diffraction Study ◽

Tensile Deformation ◽

Deformation Behaviour ◽

Neutron Diffraction Study ◽

In Situ Neutron Diffraction

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

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.345-346.41 ◽

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.

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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 ◽

10.3390/met9050482 ◽

2019 ◽

Vol 9 (5) ◽

pp. 482 ◽

Cited By ~ 2

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.

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In Situ Neutron Diffraction Studies of Phase Transformations in Si - Mn TRIP Steel

Materials Science Forum ◽

10.4028/www.scientific.net/msf.490-491.275 ◽

2005 ◽

Vol 490-491 ◽

pp. 275-280

Author(s):

O. Muránsky ◽

Petr Lukáš ◽

Petr Šittner ◽

Jozef Zrník ◽

P. Jenčuš ◽

...

Keyword(s):

Neutron Diffraction ◽

Trip Steel ◽

High Strength ◽

Phase Evolution ◽

In Situ Monitoring ◽

Trip Steels ◽

Bainite Microstructure ◽

In Situ Neutron Diffraction ◽

Strength And Ductility

High strength and ductility of the TRIP steels is often attributed to the transformation induced plasticity effect resulting from the strain induced martensitic transformation of the retained austenite in the bainite microstructure. The present work reports results of in-situ neutron diffraction experiments focused on monitoring the phase evolution in two TRIP steel samples (two different thermomechanical treatments) subjected to tensile loading at room temperature. Comparison of the single lineprofile analysis of reactor data (TKSN-400 at NPI Rez) and multi lineprofile analysis of data obtained at spallation neutron source (diffractometer ENGIN-X at ISIS RAL Chilton) suggests that the former can be used in the first approximation for in-situ monitoring of the phase evolution in TRIP steels subjected to mechanical loads.

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