The Experts below are selected from a list of 16077 Experts worldwide ranked by ideXlab platform
Jilt Sietsma - One of the best experts on this subject based on the ideXlab platform.
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Size Distribution of Retained Austenite in Phosphorus-Containing TRIP Steels
Materials Science Forum, 2007Co-Authors: L. Zhao, Niels Van Dijk, E.r. Peekstok, Ojin Tegus, Ekkes Brück, Jilt SietsmaAbstract:The present work investigates the influence of phosphorus addition on the size distribution of Retained Austenite in TRIP steels containing 0.01%, 0.09% and 0.14% phosphorus. The size of Retained Austenite is measured by means of neutron depolarization technique and optical microscopy. It is found that the addition of phosphorous increases the size of the larger intergranular and inter-ferritic Austenite grains and therefore also increases the volume fraction of Retained Austenite due to the strengthening effect of phosphorous on the surrounding ferrite and bainite grains. For all phosphorous additions the most frequently observed Austenite size is around 0.2 μm, which is probably corresponds to the interlath film-type Retained Austenite. The average grain size from the neutron depolarization technique agrees in general with that from the optical microscopy and it is suggested that the accuracy can be improved by further development of the data analysis by taking into account the preferred shape and orientation of the Austenite grains.
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Evolution and thermal stability of Retained Austenite in SAE 52100 bainitic steel
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2006Co-Authors: Natalia Luzginova, Lie Zhao, Jilt SietsmaAbstract:Abstract In this work, the evolution of Retained Austenite during isothermal bainitic heat treatment in SAE 52100 steel, 1.01C–1.36Cr–0.32Mn–0.25Si (wt.%), is investigated with optical microscopy, X-ray diffraction and thermo-magnetic measurements. A significant amount of Austenite is Retained in the material. The dependence of the volume fraction of Retained Austenite on bainitic holding time at 503 K shows a maximum at 45 min. It has been demonstrated that the increase of volume fraction of Retained Austenite occurs as a result of the increased carbon concentration. The thermal stability of Austenite is investigated. The temperature at which Retained Austenite starts to decompose to ferrite and carbides upon heating varies with bainitic holding time. The transformation of Austenite to martensite during cooling till 10 K is found to be not complete, and a large amount of Austenite remains untransformed.
Lianbo Wang - One of the best experts on this subject based on the ideXlab platform.
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Microstructures and stability of Retained Austenite in TRIP steels
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2006Co-Authors: X D Wang, B. Huang, Yonghua Rong, Lianbo WangAbstract:Abstract Transformation induced plasticity (TRIP) steels exhibit a combination of high strength and ductility due to their multi-phase microstructure, including ferrite, bainite and Retained Austenite which transforms to martensite under the external stress. The characterization of microstructures is necessary for understanding the relationship between microstructure and property. In the present work, an effort to determine the volume fraction of various phases was made for the conventional TRIP steel containing silicon. The microstructures in the TRIP steel were characterized by optical microscopy, scanning electron microscopy and transmission electron microscopy, especially, an effective method was developed to identify multi-phase microstructures by atomic force microscopy based on the height difference. Furthermore, the stability of Retained Austenite determining TRIP effect was evaluated by electrical resistance tests and tensile tests. The results show that Retained Austenite does not generate martensitic transformation at −80 °C and exhibits a good thermodynamic stability, and the transition temperature from stress-induced martensitic transformation to strain-induced martensitic transformation is determined as about −5 °C, and thus strain-induced martensitic transformation over −5 °C (somewhat lower than room temperature) is favorable for the application of TRIP steels in the automobile industry.
Petr Šittner - One of the best experts on this subject based on the ideXlab platform.
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investigation of Retained Austenite stability in mn si trip steel in tensile deformation condition
Journal of achievements in materials and manufacturing engineering, 2006Co-Authors: Ondrej Muránsky, P Lukas, Jozef Zrník, P. Osiński, Petr ŠittnerAbstract:Purpose: The aim of this study is to contribute to a better understanding of the role of the key factors governing the formation of multiphase TRIP aided steel. Design/methodology/approach: The present work reports the results of in-situ neutron diffraction experiments focused on monitoring the phase evolution in three TRIP steel samples subjected to different thermomechanical processing and mechanical loading to evaluate the stability of Retained Austenite. Findings: In-situ neutron diffraction experiments allowed characterizing the elastoplastic properties of the phases present in TRIP steel. These properties have strong influence on the transformation behaviour of the Retained Austenite during the straining and also critical effect on general mechanical properties of TRIP steel. Research limitations/implications: The precise, fast and cheap measurement of the amount of Retained Austenite in multiphase structure is a basic limitation for further research work, improvement and development control of TRIP steels. Practical implications: It is believed that not only the sufficient volume fraction of the Retained Austenite is the prerequisite to achieve convenient conditions for TRIP effect in low-alloyed steels. Originality/value: It was found that not only volume fraction of Retained Austenite has the influence on mechanical properties of TRIP steels, but also the state (size, distribution, carbon saturation, morphology) of Retained Austenite and the state of surrounding (α-matrix) plays important role.
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Retained Austenite stability investigation in TRIP steel using neutron diffraction
Materials Science and Engineering: A, 2006Co-Authors: Jozef Zrník, P Lukas, Petr Šittner, Ondrej Muránsky, Z. Nový, Peter HorňakAbstract:In situ neutron diffraction experiment was employed for monitoring of conditioned Austenite transformation to ferrite, and also for the Retained Austenite stability evaluation during subsequent mechanical loading. The progress in the Austenite decomposition to ferrite is monitored at different transformation temperatures. The relevant information on the course of the transformation is extracted from neutron diffraction spectra. The useful information was also obtained on the Retained Austenite stability in the TRIP steel during mechanical testing. The in situ neutron diffraction experiments were conducted at two different diffractometers to assess the reliability of the neutron diffraction technique at monitoring the transformation of the Retained Austenite during room temperature tensile testing. In both experiments the neutron investigation was focused on the volume fraction quantification of the Retained Austenite as well as on internal stresses rising in structure phases due to the Retained Austenite transformation.
Jozef Zrník - One of the best experts on this subject based on the ideXlab platform.
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investigation of Retained Austenite stability in mn si trip steel in tensile deformation condition
Journal of achievements in materials and manufacturing engineering, 2006Co-Authors: Ondrej Muránsky, P Lukas, Jozef Zrník, P. Osiński, Petr ŠittnerAbstract:Purpose: The aim of this study is to contribute to a better understanding of the role of the key factors governing the formation of multiphase TRIP aided steel. Design/methodology/approach: The present work reports the results of in-situ neutron diffraction experiments focused on monitoring the phase evolution in three TRIP steel samples subjected to different thermomechanical processing and mechanical loading to evaluate the stability of Retained Austenite. Findings: In-situ neutron diffraction experiments allowed characterizing the elastoplastic properties of the phases present in TRIP steel. These properties have strong influence on the transformation behaviour of the Retained Austenite during the straining and also critical effect on general mechanical properties of TRIP steel. Research limitations/implications: The precise, fast and cheap measurement of the amount of Retained Austenite in multiphase structure is a basic limitation for further research work, improvement and development control of TRIP steels. Practical implications: It is believed that not only the sufficient volume fraction of the Retained Austenite is the prerequisite to achieve convenient conditions for TRIP effect in low-alloyed steels. Originality/value: It was found that not only volume fraction of Retained Austenite has the influence on mechanical properties of TRIP steels, but also the state (size, distribution, carbon saturation, morphology) of Retained Austenite and the state of surrounding (α-matrix) plays important role.
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Retained Austenite stability investigation in TRIP steel using neutron diffraction
Materials Science and Engineering: A, 2006Co-Authors: Jozef Zrník, P Lukas, Petr Šittner, Ondrej Muránsky, Z. Nový, Peter HorňakAbstract:In situ neutron diffraction experiment was employed for monitoring of conditioned Austenite transformation to ferrite, and also for the Retained Austenite stability evaluation during subsequent mechanical loading. The progress in the Austenite decomposition to ferrite is monitored at different transformation temperatures. The relevant information on the course of the transformation is extracted from neutron diffraction spectra. The useful information was also obtained on the Retained Austenite stability in the TRIP steel during mechanical testing. The in situ neutron diffraction experiments were conducted at two different diffractometers to assess the reliability of the neutron diffraction technique at monitoring the transformation of the Retained Austenite during room temperature tensile testing. In both experiments the neutron investigation was focused on the volume fraction quantification of the Retained Austenite as well as on internal stresses rising in structure phases due to the Retained Austenite transformation.
Peter Hodgson - One of the best experts on this subject based on the ideXlab platform.
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effect of Retained Austenite on wear resistance of nanostructured dual phase steels
Materials Science and Technology, 2016Co-Authors: Peter HodgsonAbstract:Nanostructured super bainitic and quenching–partitioning (Q&P) martensitic steels with a significant amount of Retained Austenite obtained by low temperature bainitic transformation and Q&P respectively were studied to explore the effect of Retained Austenite on stirring wear resistance. The results suggest that the Q&P martensitic steel significantly enhanced the hardness of the worn surface (from 674 to 762 HV1) and increased the thickness of the deformed layer (∼3.3 μm), compared to the nanostructured bainitic steel. The underlying reason is that the Q&P martensitic steel has a higher stability of Retained Austenite thereby providing a superior transformation induced plasticity effect to increase surface hardness and reduce wear rate during the wear process.
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Selective Dissolution of Retained Austenite in Nanostructured Bainitic Steels
Advanced Engineering Materials, 2013Co-Authors: Oluwole Kazum, Mathan Bobby Kannan, Ilana Timokhina, Hossein Beladi, Peter Hodgson, Shahin KhoddamAbstract:Nanostructured bainitic steels, containing bainitic ferrite laths and Retained Austenite films, formed at two different isothermal temperatures were compared for corrosion behavior in chloride-containing solution using electrochemical techniques. The potentiodynamic polarization results suggest that nanostructured bainite formed at 200 °C exhibits marginally higher corrosion resistance compared with that at 350 °C. Post-corrosion analysis of the galvanostatically polarized samples revealed localized corrosion for both the steels, but the degree of attack was higher in the 350 °C steel than in the 200 °C steel. The localized corrosion attack was due to selective dissolution of the Retained Austenite phase. The higher volume fraction and larger size of Retained Austenite in the 350 °C steel as compared to that of the 200 °C steel contributed to the pronounced corrosion attack in the 350 °C steel.
