ORCID Profile
0000-0003-1989-0835
Current Organisation
Deakin University - Geelong Campus at Waurn Ponds
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Publisher: Elsevier BV
Date: 09-2019
Publisher: Elsevier BV
Date: 04-2007
Publisher: Elsevier BV
Date: 2014
Publisher: Elsevier BV
Date: 02-2006
Publisher: Springer Science and Business Media LLC
Date: 23-05-2020
Publisher: Springer Science and Business Media LLC
Date: 13-04-2018
Publisher: Elsevier BV
Date: 05-2021
Publisher: Trans Tech Publications, Ltd.
Date: 06-2011
DOI: 10.4028/WWW.SCIENTIFIC.NET/SSP.172-174.741
Abstract: 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.
Publisher: Elsevier BV
Date: 08-2011
Publisher: International Union of Crystallography (IUCr)
Date: 16-02-2016
DOI: 10.1107/S1600576716000418
Abstract: In situ neutron diffraction, transmission electron microscopy (TEM) and atom probe tomography (APT) have been used to study the early stages of bainite transformation in a 2 mass% Si nano-bainitic steel. It was observed that carbon redistribution between the bainitic ferrite and retained austenite at the early stages of the bainite transformation at low isothermal holding occurred in the following sequence: (i) formation of bainitic ferrite nuclei within carbon-depleted regions immediately after the beginning of isothermal treatment (ii) carbon partitioning immediately after the formation of bainitic ferrite nuclei but substantial carbon diffusion only after 33 min of bainite isothermal holding (iii) formation of the carbon-enriched remaining austenite in the vicinity of bainitic laths at the beginning of the transformation (iv) segregation of carbon to the dislocations near the austenite/ferrite interface and (v) homogeneous redistribution of carbon within the remaining austenite with the progress of the transformation and with the formation of bainitic ferrite colonies. Bainitic ferrite nucleated at internal defects or bainite/austenite interfaces as well as at the prior austenite grain boundary. Bainitic ferrite has been observed in the form of an in idual layer, a colony of layers and a layer with sideplates at the early stages of transformation.
Publisher: Springer Science and Business Media LLC
Date: 27-10-2009
Publisher: Springer Science and Business Media LLC
Date: 16-05-2019
Publisher: Elsevier BV
Date: 09-2014
Publisher: Springer Science and Business Media LLC
Date: 05-10-2011
Publisher: Trans Tech Publications, Ltd.
Date: 2012
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.706-709.2047
Abstract: In the current study, a novel approach was employed to produce a unique combination of ultrafine ferrite grains and low temperature bainite in a low carbon steel with a high hardenability. The thermomechanical route included warm deformation of supercooled austenite followed by reheating in the ferrite region and then cooling to bainitic transformation regime (i.e. 400-250°C). The resultant microstructure was ultrafine ferrite grains (i.e. μm) and very fine bainite consisting of bainitic ferrite laths with high dislocation density and retained austenite films. This microstructure offers a unique combination of ultimate tensile strength and elongation due to the presence of ductile fine ferrite grains and hard low temperature bainitic ferrite laths with retained austenite films. The microstructural characteristics of bainite were studied using optical microscopy in conjunction with scanning and transmission electron microscopy techniques.
Publisher: Elsevier BV
Date: 05-2019
Publisher: Springer Science and Business Media LLC
Date: 20-05-2019
Publisher: Springer Science and Business Media LLC
Date: 20-03-2012
Publisher: MDPI AG
Date: 05-02-2015
DOI: 10.3390/MET5010206
Publisher: Springer Science and Business Media LLC
Date: 09-07-2013
Publisher: Springer Science and Business Media LLC
Date: 21-10-2008
Publisher: Springer Science and Business Media LLC
Date: 10-11-2011
Publisher: Springer Science and Business Media LLC
Date: 08-2004
Publisher: Springer Science and Business Media LLC
Date: 28-08-2013
Publisher: Informa UK Limited
Date: 2011
Publisher: Iron and Steel Institute of Japan
Date: 2004
Publisher: Trans Tech Publications, Ltd.
Date: 2012
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.706-709.2332
Abstract: The influence of pre-straining and bake-hardening on the mechanical properties of thermomechanically processed 0.2C-1.5Si-1.5Mn-0.2Mo-0.004Nb (wt%) steel was analysed using tensile test, transmission electron microscopy (TEM) and atom probe tomography (APT). This steel after processing had high strength (~1200MPa) and good ductility (~20%) due to the formation of fully bainitic microstructure with nanolayers of bainitic ferrite and retained austenite. The bake hardening (BH) of pre-strained (PS) s les increased the yield strength of steel up to 690MPa and showed the bake-hardening response of 220MPa due to the operation of several strengthening mechanisms such as transformation induced plasticity during pre-straining and pinning the dislocations by carbon during bake-hardening treatment. The carbon content of the bainitic ferrite and retained austenite before and after bake-hardening treatment, the solute distribution between these phases and the local composition of fine Fe-C clusters and particles formed during bake-hardening treatment was calculated using APT. The bainitic ferrite and retained austenite microstructural characteristics such as thickness of the layers and their dislocation density before and after bake-hardening treatment were studied using TEM.
Publisher: Wiley
Date: 06-2002
Publisher: Informa UK Limited
Date: 10-2013
Publisher: Iron and Steel Institute of Japan
Date: 2010
Publisher: Springer Science and Business Media LLC
Date: 24-04-2017
Publisher: Trans Tech Publications, Ltd.
Date: 2010
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.638-642.148
Abstract: The performance of multiphase steels with high strength and improved toughness or ductility, such as intercritically annealed dual-phase (DP) and transformation-induced plasticity (TRIP) steels, is of key importance to the automotive industry. In this work we have considered the entire manufacturing process and the effects of this on the final product performance. These steels are formed to produce the required final shape and then the car is paint baked. In this work we also consider the effect of cold working and bake hardening on the fatigue life of the components.
Publisher: Elsevier BV
Date: 04-2013
Publisher: Elsevier BV
Date: 09-2017
Publisher: Springer Science and Business Media LLC
Date: 10-2018
Publisher: Trans Tech Publications, Ltd.
Date: 06-2011
DOI: 10.4028/WWW.SCIENTIFIC.NET/SSP.172-174.1249
Abstract: A 0.79C-1.5Si-1.98Mn-0.98Cr-0.24Mo-1.06Al-1.58Co (wt%) steel was isothermally heat treated at 350°C bainitic transformation temperature for 1 day to form fully bainitic structure with nano-layers of bainitic ferrite and retained austenite, while a 0.26C-1.96Si-2Mn-0.31Mo (wt%) steel was subjected to a successive isothermal heat treatment at 700°C for 300 min followed by 350°C for 120 min to form a hybrid microstructure consisting of ductile ferrite and fine scale bainite. The dislocation density and morphology of bainitic ferrite, and retained austenite characteristics such as size, and volume fraction were studied using Transmission Electron Microscopy. It was found that bainitic ferrite has high dislocation density for both steels. The retained austenite characteristics and bainite morphology were affected by composition of steels. Atom Probe Tomography (APT) has the high spatial resolution required for accurate determination of the carbon content of the bainitic ferrite and retained austenite, the solute distribution between these phases and calculation of the local composition of fine clusters and particles that allows to provide detailed insight into the bainite transformation of the steels. The carbon content of bainitic ferrite in both steels was found to be higher compared to the para-equilibrium level of carbon in ferrite. APT also revealed the presence of fine C-rich clusters and Fe-C carbides in bainitic ferrite of both steels.
Publisher: Elsevier BV
Date: 2017
Publisher: Elsevier BV
Date: 04-2016
Publisher: Trans Tech Publications, Ltd.
Date: 07-2013
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.762.14
Abstract: Two steels, ferritic, high strength with interphase precipitation and nanobainitic, were used to show the advances in and application of atom probe. The coexistence of the nanoscale, interphase Nb-Mo-C clusters and stoichiometric MC nanoparticles was found in the high strength steel after thermomechanical processing. Moreover, the segregation of carbon at different heterogeneous sites such as grain boundary that reduces the solute element available for fine precipitation was observed. The APT study of the solutes redistribution between the retained austenite and bainitic ferrite in the nanobainitic steel revealed: (i) the presence of two types of the retained austenite with higher and lower carbon content and (ii) segregation of carbon at the local defects such as dislocations in the bainitic ferrite during the isothermal hold.
Publisher: Elsevier BV
Date: 02-2012
Publisher: MDPI AG
Date: 31-10-2018
DOI: 10.3390/MET8110886
Abstract: Phase transformations are significant phenomena determining the final properties of a wide range of materials. [...]
Publisher: Elsevier BV
Date: 05-2018
Publisher: Elsevier BV
Date: 03-2007
Publisher: Trans Tech Publications, Ltd.
Date: 03-2010
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.97-101.2163
Abstract: The refinement of microstructure is the most generally accepted approach to simultaneously improve the strength and toughness in steels. In the current study, the role of dynamic/static phase transformation on the ferrite grain refinement was investigated using different thermomechanical processing routes. A Ni-30Fe austenitic model alloy was also used to investigate the substructure character formed during deformation. It was revealed that the microstructure of steel could further be refined to the nanoscale through both the control of processing route and steel composition design.
Publisher: Springer Science and Business Media LLC
Date: 27-07-2016
Publisher: Elsevier BV
Date: 2018
Publisher: Elsevier BV
Date: 06-2011
Publisher: Elsevier BV
Date: 02-2019
Publisher: Trans Tech Publications, Ltd.
Date: 11-2013
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.773-774.257
Abstract: The aim of the present study was to investigate the role of deformation temperature on the active deformation mechanisms in a 0.6C-18Mn-1.5Al (wt%) TWIP steel. The tensile testing was performed at different temperatures, ranging from ambient to 400°C at a constant strain rate of 10 -3 s -1 . The microstructure characterization was carried out using a scanning electron microscopy. The deformation temperature revealed a significant effect on the active deformation mechanisms (i.e. slip versus twinning), resulting in different microstructure evolution and mechanical properties. At the room temperature, the mechanical twinning was the dominant deformation mechanism, enhancing both the strength and ductility. Dynamic strain aging (DSA) effect was observed at different deformation temperatures, though it was more pronounced at higher temperatures. The volume fraction of deformation twins significantly reduced with an increase in the deformation temperature, deteriorating the mechanical behavior. There was a transition temperature (~300°C), above which the mechanical twinning was hardly observed in the microstructure even at fracture, resulting in low ductility and strength. The current observation can be explained through the change in the stacking fault energy with the deformation temperature.
Publisher: Springer Science and Business Media LLC
Date: 23-05-2013
Publisher: Elsevier BV
Date: 02-2021
Publisher: Informa UK Limited
Date: 02-2001
Publisher: Elsevier BV
Date: 10-2013
Publisher: Informa UK Limited
Date: 04-2001
Publisher: Elsevier BV
Date: 12-2011
Publisher: Elsevier BV
Date: 11-2013
Publisher: Springer Science and Business Media LLC
Date: 06-01-2009
Publisher: Elsevier BV
Date: 06-2008
Publisher: Wiley
Date: 20-11-2014
Publisher: Elsevier BV
Date: 10-2006
Publisher: Springer Science and Business Media LLC
Date: 27-03-2018
Publisher: Informa UK Limited
Date: 18-12-2023
Publisher: Trans Tech Publications, Ltd.
Date: 06-2010
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.654-656.1255
Abstract: As-received hot-rolled 5.6 mm thick IF steel sheet was symmetrically/asymmetrically cold rolled at room temperature down to 1.9 mm. The asymmetric rolling was carried out in monotonic (an idle roll is always on the same side of the sheet) and reversal (the sheet was turned 180º around the rolling direction between passes) modes. Microstructure, texture and mechanical properties were analysed. The observed differences in structure and mechanical properties were modest, and therefore further investigation of the effects of other kinds of asymmetry is suggested.
Publisher: Elsevier BV
Date: 07-2016
Publisher: Elsevier BV
Date: 05-2007
Publisher: Springer Science and Business Media LLC
Date: 03-03-2016
DOI: 10.1557/JMR.2016.73
Publisher: MDPI AG
Date: 26-06-2017
DOI: 10.3390/MET7070234
Abstract: The nitrocarburising response of low transformation temperature ultrafine and nanoscale bainitic steel was investigated and compared with martensite and pearlite from the same steel composition. It was found that the retained austenite content of the bainitic steel dictated the core hardness after nitrocarburising. The refined bainitic structure showed improvements in the nitriding depth and hardness of the nitrocarburised layer, compared to coarser grained martensitic and pearlitic structures, possibly due to the fine structure and the distribution of nitride forming elements.
Publisher: Springer Science and Business Media LLC
Date: 08-2003
Publisher: Trans Tech Publications, Ltd.
Date: 2013
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.738-739.212
Abstract: Advances in the development of new high strength steels have resulted in microstructures containing significant volume fractions of retained austenite. The transformation of retained austenite to martensite upon straining contributes towards improving the ductility. However, in order to gain from the above beneficial effect, the volume fraction, size, morphology and distribution of the retained austenite need to be controlled. In this regard, it is well known that carbon concentration in the retained austenite is responsible for its chemical stability, whereas its size and morphology determines its mechanical stability. Thus, to achieve the required mechanical properties, control of the processing parameters affecting the microstructure development is essential.
Publisher: Springer Science and Business Media LLC
Date: 14-06-2014
Publisher: Trans Tech Publications, Ltd.
Date: 06-2010
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.654-656.102
Abstract: The effect of composition and processing schedule on the microstructure of C-Mn-Si-Mo-(Al)-(Nb) steels containing nano-bainite was studied using transmission electron microscopy (TEM) and atom probe tomography (APT). The major phase formed in all steels was nano-bainite. However, the steels with lower carbon and alloying addition content subjected to TMP had better mechanical properties than high alloyed steel after isothermal treatment. The presence of ferrite in the microstructure can improve not only ductility but lead to the formation of retained austenite with optimum chemical stability.
Publisher: Springer Science and Business Media LLC
Date: 30-11-2011
Publisher: Elsevier BV
Date: 02-2008
Publisher: Springer Science and Business Media LLC
Date: 29-08-2007
Publisher: Elsevier
Date: 2017
Publisher: Elsevier BV
Date: 2001
Publisher: Walter de Gruyter GmbH
Date: 12-2021
DOI: 10.3139/146.110239
Abstract: This work focuses on the deformation behavior of an ultra-fine grained Al-Mg-Si alloy processed by equal channel angular pressing over a wide range of temperatures and strain rates. The effect of temperature and strain rate on the homogeneity of plastic deformation, the evolution of microstructure, the strain rate sensitivity and the underlying deformation mechanisms are investigated. It is demonstrated that the localization of plastic deformation at the micro scale is triggered by grain boundary sliding due to grain boundary diffusion. The contributions of different deformation mechanisms during the plastic deformation of the material are discussed.
Publisher: Trans Tech Publications, Ltd.
Date: 07-05-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.922.676
Abstract: High-Mn Twinning Induced Plasticity (TWIP) steels have superior mechanical properties, which make them promising materials in automotive industry to improve the passenger safety and the fuel consumption. The TWIP steels are characterized by high work hardening rates due to continuous mechanical twin formation during the deformation. Mechanical twinning is a unique deformation mode, which is highly governed by the stacking fault energy (SFE). The composition of steel alloy was Fe-18Mn-0.6C-1Al (wt.%) with SFE of about 25-30 mJ/m 2 at room temperature. The SFE ensures the mechanical twinning to be the main deformation mechanism at room temperature. The microstructure, mechanical properties, work hardening behaviour and SFE of the steel was studied at the temperature range of ambient≤T[°C]≤400 ° C. The mechanical properties were determined using Instron tensile testing machine with 30kN load cell and strain rate of 10 -3 s -1 and the work hardening behaviour curves were generated using true stress and true strain data. The microstructure after deformation at different temperatures was examined using Zeiss Supra 55VP SEM. It was found that an increase in the deformation temperature raised the SFE resulting in the deterioration of the mechanical twinning that led to decrease not only in the strength but also in the total strain of the steel. A correlation between the temperature, the SFE, the mechanical twinning, the mechanical properties and the work hardening rate was also found.
Publisher: Iron and Steel Institute of Japan
Date: 2005
Publisher: Springer Science and Business Media LLC
Date: 20-08-2018
Publisher: Elsevier BV
Date: 12-1999
Publisher: Elsevier BV
Date: 03-2009
Publisher: Elsevier BV
Date: 06-2018
Publisher: Springer Science and Business Media LLC
Date: 28-09-2021
Publisher: Trans Tech Publications, Ltd.
Date: 06-2011
DOI: 10.4028/WWW.SCIENTIFIC.NET/SSP.172-174.123
Abstract: A 0.79C-1.5Si-1.98Mn-0.98Cr-0.24Mo-1.06Al-1.58Co (wt%) steel was isothermally heat treated at 200°C for 10 days to form a nano-scale bainitic microstructure consisting of nanobainitic ferrite laths with high dislocation density and retained austenite films. The crystallographic analysis using TEM and EBSD revealed that the bainitic ferrite laths are close to the Nishiyama-Wassermann orientation relationship with the parent austenite. There was only one type of packet identified in a given transformed austenite grain. Each packet consisted of two different blocks having variants with the same habit plane, but different crystallographic orientations. The presence of fine C-rich clusters and Fe-C carbides with a wide range of compositions in bainitic ferrite was revealed by Three-dimensional Atom Probe Tomography (APT). The high carbon content of bainitic ferrite compared to the para-equilibrium level of carbon in ferrite, absence of segregation of carbon to the austenite/bainitic ferrite interface and absence of partitioning of substitutional elements between the retained austenite and bainitic ferrite were also found using APT.
Publisher: Springer Science and Business Media LLC
Date: 17-09-2012
Publisher: Elsevier BV
Date: 03-2018
Publisher: Informa UK Limited
Date: 04-2011
Publisher: Elsevier BV
Date: 02-2014
Publisher: Elsevier BV
Date: 05-2008
Publisher: Elsevier BV
Date: 02-2022
Publisher: Elsevier BV
Date: 04-2017
Publisher: Springer Science and Business Media LLC
Date: 04-08-2016
Publisher: Elsevier BV
Date: 2014
Publisher: Elsevier BV
Date: 06-2008
Publisher: Elsevier BV
Date: 12-2016
Publisher: Informa UK Limited
Date: 21-04-2022
Publisher: Elsevier BV
Date: 03-2018
Publisher: Trans Tech Publications, Ltd.
Date: 2012
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.706-709.2788
Abstract: In the present study, the effects of kinematic and geometric asymmetries in rolling during multi-pass processing of IF steel are examined. The theoretical investigation by final element simulations and experimental investigations by means of electron-backscatter diffraction analysis and tensile tests suggest that asymmetric rolling increases the total imposed strain compared to symmetric rolling, and largely re-distributes the strain components due to additional shear. This enhances the intensity of grain refinement, strengthens and tilts crystallographic orientations, and increases mechanical strength. The effect is highest in the asymmetric rolling with differential roll diameters.
Location: Australia
Start Date: 2015
End Date: 2017
Funder: Australian Research Council
View Funded ActivityStart Date: 2007
End Date: 2007
Funder: Australian Research Council
View Funded ActivityStart Date: 2009
End Date: 2011
Funder: Australian Research Council
View Funded ActivityStart Date: 2007
End Date: 2010
Funder: Australian Research Council
View Funded ActivityStart Date: 2012
End Date: 2012
Funder: Australian Research Council
View Funded ActivityStart Date: 2004
End Date: 2008
Funder: Australian Research Council
View Funded ActivityStart Date: 2012
End Date: 2012
Funder: Australian Research Council
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