The Experts below are selected from a list of 5334 Experts worldwide ranked by ideXlab platform
Ahmed Charaï - One of the best experts on this subject based on the ideXlab platform.
-
effect of the bainitic transformation temperature on retained Austenite Fraction and stability in ti microalloyed trip steels
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009Co-Authors: Myriam Dumont, X Bano, A Kammouni, Ahmed Charaï, W. Saikaly, C. MarteauAbstract:TRIP properties in four hot-rolled microalloyed steels were studied as a function of bainitic domain entrance temperature. It was found that this temperature affects the size and morphology of the retained Austenite grains. Size and morphology was shown to play a role on the stability of the retained Austenite. This stability was shown to be the major factor affecting the mechanical properties of these steels. In the case of the lowest bainitic temperature, the TRIP effect is hindered due to the premature transformation of Austenite into martensite probably due to an insufficient carbon enrichment of the small Austenite grains. Moreover the bainitic treatment performed at the highest temperature contained a very low volume Fraction of retained Austenite that does not transform even under deformation. Using TEM and the Kikuchi-line method, it was shown that the sample that did not undergo a phase transformation during FIB milling had a carbon concentration in its retained Austenite grains of approximately 1.7%.
-
effect of the bainitic transformation temperature on retained Austenite Fraction and stability in ti microalloyed trip steels
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009Co-Authors: Myriam Dumont, X Bano, A Kammouni, Ahmed Charaï, W. Saikaly, C. MarteauAbstract:TRIP properties in four hot-rolled microalloyed steels were studied as a function of bainitic domain entrance temperature. It was found that this temperature affects the size and morphology of the retained Austenite grains. Size and morphology was shown to play a role on the stability of the retained Austenite. This stability was shown to be the major factor affecting the mechanical properties of these steels. In the case of the lowest bainitic temperature, the TRIP effect is hindered due to the premature transformation of Austenite into martensite probably due to an insufficient carbon enrichment of the small Austenite grains. Moreover the bainitic treatment performed at the highest temperature contained a very low volume Fraction of retained Austenite that does not transform even under deformation. Using TEM and the Kikuchi-line method, it was shown that the sample that did not undergo a phase transformation during FIB milling had a carbon concentration in its retained Austenite grains of approximately 1.7%.
Han Dong - One of the best experts on this subject based on the ideXlab platform.
-
effect of reverted Austenite Fraction on hydrogen embrittlement of trip aided medium mn steel 0 1c 5mn
Engineering Failure Analysis, 2019Co-Authors: Yongjian Zhang, Wen Quan Cao, Weijun Hui, Xiaoli Zhao, Cunyu Wang, Han DongAbstract:Abstract The present work was attempted to evaluate the influence of reverted Austenite (RA) Fraction on hydrogen embrittlement (HE) of a hot rolled transformation-induced plasticity (TRIP)-aided medium Mn steel (0.1C-5Mn) by using electrochemical charging, slow strain rate tensile (SSRT) test and thermal desorption spectrometry (TDS) analysis. Different volume Fractions of RA (~10–30 vol%) in the tested steel sheet were obtained by changing intercritical annealing time. The result of TDS analysis demonstrated that the charged hydrogen is primarily diffusible hydrogen corresponding to low-temperature hydrogen desorption peak and its concentration increases almost linearly with an increase in the volume Fraction of RA. It was found that the intercritically annealed specimen exhibits an increasing susceptibility to HE with an increase in the volume Fraction of RA primarily due to the increased RA transformation to martensite during tensile deformation. It is thus regarded that the TRIP effect is harmful to the HE resistance of TRIP-aided steels, and therefore both the mechanical stability and amount of RA have a strong influence on the HE behavior of TRIP-aided medium Mn steel.
-
phase transformation behavior of cold rolled 0 1c 5mn steel during heating process studied by differential scanning calorimetry
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2015Co-Authors: Wen Quan Cao, Cunyu Wang, Han DongAbstract:Abstract The microstructural evolution of a cold-rolled steel 0.1C–5Mn was characterized by SEM and EBSD, and the α → γ phase transformation of the steel was determined by differential scanning calorimetry (DSC) upon heating. The retained Austenite Fraction and the dislocation density were examined by XRD. Based on the DSC data, the Kissinger׳s method was used to calculate the activation energy of the cold rolled steel. The activation energy of 363–824 kJ/mol suggested a sluggish phase transformation during the heating process and it showed an increase trend with the increase of thickness reduction which was affected by the density of the dislocation and the drag effect by the solute Mn. The stored energy (14–30 J/g) was associated with energy released from the α → γ transformation during the heating process. Based on the effects of temperature on the phase transformation behavior, the cold rolled medium-Mn steel with different thickness reductions were annealed at the onset phase transformation temperature with 5 min and 6 h, which results in a very good combination strength and ductility.
-
effects of cold rolling reduction on retained Austenite Fraction and mechanical properties of high si trip steel
Journal of Iron and Steel Research International, 2013Co-Authors: F U Yongtao, Wen Quan Cao, Jing Liu, Jie Shi, Han DongAbstract:Abstract Transformation-induced plasticity-aided steel [TRIP steel (0. 4C-1. 5Si-1. 5Mn)] was rolled at room temperature to different thickness reductions (0, 4%, 10%, 20%, 40%, and 60%). The mechanical properties, microstructure and Austenite Fractions of the rolled samples were measured by tensile test, electron back scattered difFraction (EBSD) and X-ray difFraction (XRD) for each rolling. The deformation behavior was studied based on the analysis of the mechanical properties and microstructure of steel after tensile deformation, aiming at understanding the effects of cold rolling reduction on the decay behavior of the Austenite and the change of mechanical properties of the TRIP steels. It was found that increasing rolling reduction increases the yield stress gradually but decreases the total elongation significantly. It is very interesting that after 10% rolling reduction the yield stress is about 1000 MPa but still with 20% total elongation, which gives an excellent combination of yield strength and ductility. Based on the XRD results, it was revealed that in both rolling and tension the Austenite volume Fraction monotonically decayed with the increase of rolling strain, but the decaying rate is faster in tension than in rolling, which may be ascribed to the higher temperature in rolled specimens than in the tensioned ones during deformation. Experimental results and theoretical reasoning indicate that the decreasing trend of Austenite volume Fraction with strain can be formulated by a unique equation.
-
heat treatment effects on the microstructure and mechanical properties of a medium manganese steel 0 2c 5mn
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2012Co-Authors: J Zhao, Wen Quan Cao, Cunyu Wang, Jie Shi, Chang Wang, Han DongAbstract:Abstract Microstructures and mechanical properties of 0.2C–5Mn steel processed under different heat treatment conditions were examined by scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and X-ray difFraction (XRD). It was found that high temperature austenization (above Ac3) resulted in a full martensite structure after quenching, which gradually transformed into the ferrite/Austenite duplex structure during the following annealing process. However, austenization in the intercritical region (between Ac1 and Ac3) gave a duplex structure after quenching, which was nearly not affected by followed annealing process. The ultrahigh strength ∼1000 MPa and total elongation ∼40% were only obtained in the specimens with 6 h annealing at 650 °C under both heat treatment conditions. However, the excellent mechanical properties could be obtained in the intercritically austenitized samples with only 10 min annealing at 650 °C. Based on the analysis on the relationship between microstructure and mechanical properties, it was found that the total elongation was strongly dependent on the Austenite Fraction, which was ascribed to the phase transformation induced plasticity of the large volume Fraction of Austenite. Otherwise, the dependence of the yield stress on the Austenite grain size accords with Hall-Petch equation, which implies that the Austenite is soft phase. It was concluded that 10 min annealing at 650 °C was enough to obtain a large volume Fraction of Austenite (∼30%) in 0.2C–5Mn steel when the specimens were austenitized at 675 °C.
A Kammouni - One of the best experts on this subject based on the ideXlab platform.
-
effect of the bainitic transformation temperature on retained Austenite Fraction and stability in ti microalloyed trip steels
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009Co-Authors: Myriam Dumont, X Bano, A Kammouni, Ahmed Charaï, W. Saikaly, C. MarteauAbstract:TRIP properties in four hot-rolled microalloyed steels were studied as a function of bainitic domain entrance temperature. It was found that this temperature affects the size and morphology of the retained Austenite grains. Size and morphology was shown to play a role on the stability of the retained Austenite. This stability was shown to be the major factor affecting the mechanical properties of these steels. In the case of the lowest bainitic temperature, the TRIP effect is hindered due to the premature transformation of Austenite into martensite probably due to an insufficient carbon enrichment of the small Austenite grains. Moreover the bainitic treatment performed at the highest temperature contained a very low volume Fraction of retained Austenite that does not transform even under deformation. Using TEM and the Kikuchi-line method, it was shown that the sample that did not undergo a phase transformation during FIB milling had a carbon concentration in its retained Austenite grains of approximately 1.7%.
-
effect of the bainitic transformation temperature on retained Austenite Fraction and stability in ti microalloyed trip steels
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009Co-Authors: Myriam Dumont, X Bano, A Kammouni, Ahmed Charaï, W. Saikaly, C. MarteauAbstract:TRIP properties in four hot-rolled microalloyed steels were studied as a function of bainitic domain entrance temperature. It was found that this temperature affects the size and morphology of the retained Austenite grains. Size and morphology was shown to play a role on the stability of the retained Austenite. This stability was shown to be the major factor affecting the mechanical properties of these steels. In the case of the lowest bainitic temperature, the TRIP effect is hindered due to the premature transformation of Austenite into martensite probably due to an insufficient carbon enrichment of the small Austenite grains. Moreover the bainitic treatment performed at the highest temperature contained a very low volume Fraction of retained Austenite that does not transform even under deformation. Using TEM and the Kikuchi-line method, it was shown that the sample that did not undergo a phase transformation during FIB milling had a carbon concentration in its retained Austenite grains of approximately 1.7%.
Myriam Dumont - One of the best experts on this subject based on the ideXlab platform.
-
effect of the bainitic transformation temperature on retained Austenite Fraction and stability in ti microalloyed trip steels
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009Co-Authors: Myriam Dumont, X Bano, A Kammouni, Ahmed Charaï, W. Saikaly, C. MarteauAbstract:TRIP properties in four hot-rolled microalloyed steels were studied as a function of bainitic domain entrance temperature. It was found that this temperature affects the size and morphology of the retained Austenite grains. Size and morphology was shown to play a role on the stability of the retained Austenite. This stability was shown to be the major factor affecting the mechanical properties of these steels. In the case of the lowest bainitic temperature, the TRIP effect is hindered due to the premature transformation of Austenite into martensite probably due to an insufficient carbon enrichment of the small Austenite grains. Moreover the bainitic treatment performed at the highest temperature contained a very low volume Fraction of retained Austenite that does not transform even under deformation. Using TEM and the Kikuchi-line method, it was shown that the sample that did not undergo a phase transformation during FIB milling had a carbon concentration in its retained Austenite grains of approximately 1.7%.
-
effect of the bainitic transformation temperature on retained Austenite Fraction and stability in ti microalloyed trip steels
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009Co-Authors: Myriam Dumont, X Bano, A Kammouni, Ahmed Charaï, W. Saikaly, C. MarteauAbstract:TRIP properties in four hot-rolled microalloyed steels were studied as a function of bainitic domain entrance temperature. It was found that this temperature affects the size and morphology of the retained Austenite grains. Size and morphology was shown to play a role on the stability of the retained Austenite. This stability was shown to be the major factor affecting the mechanical properties of these steels. In the case of the lowest bainitic temperature, the TRIP effect is hindered due to the premature transformation of Austenite into martensite probably due to an insufficient carbon enrichment of the small Austenite grains. Moreover the bainitic treatment performed at the highest temperature contained a very low volume Fraction of retained Austenite that does not transform even under deformation. Using TEM and the Kikuchi-line method, it was shown that the sample that did not undergo a phase transformation during FIB milling had a carbon concentration in its retained Austenite grains of approximately 1.7%.
Wen Quan Cao - One of the best experts on this subject based on the ideXlab platform.
-
effect of reverted Austenite Fraction on hydrogen embrittlement of trip aided medium mn steel 0 1c 5mn
Engineering Failure Analysis, 2019Co-Authors: Yongjian Zhang, Wen Quan Cao, Weijun Hui, Xiaoli Zhao, Cunyu Wang, Han DongAbstract:Abstract The present work was attempted to evaluate the influence of reverted Austenite (RA) Fraction on hydrogen embrittlement (HE) of a hot rolled transformation-induced plasticity (TRIP)-aided medium Mn steel (0.1C-5Mn) by using electrochemical charging, slow strain rate tensile (SSRT) test and thermal desorption spectrometry (TDS) analysis. Different volume Fractions of RA (~10–30 vol%) in the tested steel sheet were obtained by changing intercritical annealing time. The result of TDS analysis demonstrated that the charged hydrogen is primarily diffusible hydrogen corresponding to low-temperature hydrogen desorption peak and its concentration increases almost linearly with an increase in the volume Fraction of RA. It was found that the intercritically annealed specimen exhibits an increasing susceptibility to HE with an increase in the volume Fraction of RA primarily due to the increased RA transformation to martensite during tensile deformation. It is thus regarded that the TRIP effect is harmful to the HE resistance of TRIP-aided steels, and therefore both the mechanical stability and amount of RA have a strong influence on the HE behavior of TRIP-aided medium Mn steel.
-
variation in retained Austenite content and mechanical properties of 0 2c 7mn steel after intercritical annealing
International Journal of Minerals Metallurgy and Materials, 2016Co-Authors: Wen Quan Cao, Chi Zhang, Chuan Zhao, Zhigang YangAbstract:The effects of annealing time and temperature on the retained Austenite content and mechanical properties of 0.2C–7Mn steel were studied. The retained Austenite content of 0.2C–7Mn steel was compared with that of 0.2C–5Mn steel. It is found that 0.2C–7Mn steel exhibits a similar variation trend of retained Austenite content as 0.2C–5Mn steel. However, in detail, these trends are different. 0.2C–7Mn steel contains approximately 7.5vol% retained Austenite after austenitization and quenching. The stability of the reversed Austenite in 0.2C–7Mn steel is lower than that in 0.2C–5Mn steel; in contrast, the equilibrium reversed Austenite Fraction of 0.2C–7Mn steel is substantially greater than that of 0.2C–5Mn steel. Therefore, the retained Austenite content in 0.2C–7Mn steel reaches 53.1vol%. The tensile results show that long annealing time and high annealing temperature may not favor the enhancement of mechanical properties of 0.2C–7Mn steel. The effect of retained Austenite on the tensile strength of the steel depends on the content of retained Austenite; in contrast, the 0.2% yield strength linearly decreases with increasing retained Austenite content.
-
phase transformation behavior of cold rolled 0 1c 5mn steel during heating process studied by differential scanning calorimetry
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2015Co-Authors: Wen Quan Cao, Cunyu Wang, Han DongAbstract:Abstract The microstructural evolution of a cold-rolled steel 0.1C–5Mn was characterized by SEM and EBSD, and the α → γ phase transformation of the steel was determined by differential scanning calorimetry (DSC) upon heating. The retained Austenite Fraction and the dislocation density were examined by XRD. Based on the DSC data, the Kissinger׳s method was used to calculate the activation energy of the cold rolled steel. The activation energy of 363–824 kJ/mol suggested a sluggish phase transformation during the heating process and it showed an increase trend with the increase of thickness reduction which was affected by the density of the dislocation and the drag effect by the solute Mn. The stored energy (14–30 J/g) was associated with energy released from the α → γ transformation during the heating process. Based on the effects of temperature on the phase transformation behavior, the cold rolled medium-Mn steel with different thickness reductions were annealed at the onset phase transformation temperature with 5 min and 6 h, which results in a very good combination strength and ductility.
-
effects of cold rolling reduction on retained Austenite Fraction and mechanical properties of high si trip steel
Journal of Iron and Steel Research International, 2013Co-Authors: F U Yongtao, Wen Quan Cao, Jing Liu, Jie Shi, Han DongAbstract:Abstract Transformation-induced plasticity-aided steel [TRIP steel (0. 4C-1. 5Si-1. 5Mn)] was rolled at room temperature to different thickness reductions (0, 4%, 10%, 20%, 40%, and 60%). The mechanical properties, microstructure and Austenite Fractions of the rolled samples were measured by tensile test, electron back scattered difFraction (EBSD) and X-ray difFraction (XRD) for each rolling. The deformation behavior was studied based on the analysis of the mechanical properties and microstructure of steel after tensile deformation, aiming at understanding the effects of cold rolling reduction on the decay behavior of the Austenite and the change of mechanical properties of the TRIP steels. It was found that increasing rolling reduction increases the yield stress gradually but decreases the total elongation significantly. It is very interesting that after 10% rolling reduction the yield stress is about 1000 MPa but still with 20% total elongation, which gives an excellent combination of yield strength and ductility. Based on the XRD results, it was revealed that in both rolling and tension the Austenite volume Fraction monotonically decayed with the increase of rolling strain, but the decaying rate is faster in tension than in rolling, which may be ascribed to the higher temperature in rolled specimens than in the tensioned ones during deformation. Experimental results and theoretical reasoning indicate that the decreasing trend of Austenite volume Fraction with strain can be formulated by a unique equation.
-
heat treatment effects on the microstructure and mechanical properties of a medium manganese steel 0 2c 5mn
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2012Co-Authors: J Zhao, Wen Quan Cao, Cunyu Wang, Jie Shi, Chang Wang, Han DongAbstract:Abstract Microstructures and mechanical properties of 0.2C–5Mn steel processed under different heat treatment conditions were examined by scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and X-ray difFraction (XRD). It was found that high temperature austenization (above Ac3) resulted in a full martensite structure after quenching, which gradually transformed into the ferrite/Austenite duplex structure during the following annealing process. However, austenization in the intercritical region (between Ac1 and Ac3) gave a duplex structure after quenching, which was nearly not affected by followed annealing process. The ultrahigh strength ∼1000 MPa and total elongation ∼40% were only obtained in the specimens with 6 h annealing at 650 °C under both heat treatment conditions. However, the excellent mechanical properties could be obtained in the intercritically austenitized samples with only 10 min annealing at 650 °C. Based on the analysis on the relationship between microstructure and mechanical properties, it was found that the total elongation was strongly dependent on the Austenite Fraction, which was ascribed to the phase transformation induced plasticity of the large volume Fraction of Austenite. Otherwise, the dependence of the yield stress on the Austenite grain size accords with Hall-Petch equation, which implies that the Austenite is soft phase. It was concluded that 10 min annealing at 650 °C was enough to obtain a large volume Fraction of Austenite (∼30%) in 0.2C–5Mn steel when the specimens were austenitized at 675 °C.
