Abstract:The cooling rate, density of stacking faults, austenite grain size, and temperature strongly influence the γ fcc → ε hcp → α' bcc martensite transformation in austenitic alloys. During cooling, austenitic Fe-Mn steels can partially transform to ε and α' martensites within a restricted chemical composition. Martensite formation will influence the mechanical behavior of the alloy. The microstructure evolution under three cooling rates of a hot-rolled austenitic steel, Fe-17.0Mn-0.06C (wt%), was analyzed by optic… Show more
“…The samples were first etched with nital (10%) and then with Klemm's I etchant [23,24]. For the Scanning electron microscopy (SEM) measurements, the samples were etched with Villela etchant.…”
Section: Methodsmentioning
confidence: 99%
“…For the quantification of the austenite and the and ␣ martensites, the direct comparison method was used [16], which involves the integration of the most intense peaks of each phase characterized by the (1 1 1), (2 0 0), (2 2 0), and (3 1 1) planes of austenite, the (1 1 0), (2 0 0), (2 1 1), and (2 2 0) planes of ferrite, and the (1 0 0), (0 0 2), (1 0 1), and (1 0 2) planes of martensite. The integration of the intensities was done with support of a graphic software (Origin TM ), following the methodology described by Dafé et al [23].…”
Electron backscattering diffraction (EBSD)Cold rolling Recrystallization TRIP/TWIP steel a b s t r a c t High Mn steels with Si and Al present great plasticity when deformed due to the TRIP/TWIP effect. This work evaluated the microstructural evolution and texture formation of a 17Mn-0.06C steel after hot rolling, cold rolling to 45% of thickness reduction and annealing at 700 • C for different times. The microstructural analysis was performed by means of dilatometry, X-ray diffraction (XRD), optical (OM) and scanning electron microscopy (SEM), electron backscattering diffraction EBSD and transmission electron microscopy (TEM). It was found that during the cooling process, after the steel is annealed, the athermal and ␣ martensites are formed. Tensile test results showed that the steel exhibits yield and tensile strength around 650 and 950 MPa with a total elongation around 45%. The austenite texture contains brass, copper and Goss components while the ␣ and martensites textures contain rotated cube and prismatic and pyramidal fibers, respectively.
“…The samples were first etched with nital (10%) and then with Klemm's I etchant [23,24]. For the Scanning electron microscopy (SEM) measurements, the samples were etched with Villela etchant.…”
Section: Methodsmentioning
confidence: 99%
“…For the quantification of the austenite and the and ␣ martensites, the direct comparison method was used [16], which involves the integration of the most intense peaks of each phase characterized by the (1 1 1), (2 0 0), (2 2 0), and (3 1 1) planes of austenite, the (1 1 0), (2 0 0), (2 1 1), and (2 2 0) planes of ferrite, and the (1 0 0), (0 0 2), (1 0 1), and (1 0 2) planes of martensite. The integration of the intensities was done with support of a graphic software (Origin TM ), following the methodology described by Dafé et al [23].…”
Electron backscattering diffraction (EBSD)Cold rolling Recrystallization TRIP/TWIP steel a b s t r a c t High Mn steels with Si and Al present great plasticity when deformed due to the TRIP/TWIP effect. This work evaluated the microstructural evolution and texture formation of a 17Mn-0.06C steel after hot rolling, cold rolling to 45% of thickness reduction and annealing at 700 • C for different times. The microstructural analysis was performed by means of dilatometry, X-ray diffraction (XRD), optical (OM) and scanning electron microscopy (SEM), electron backscattering diffraction EBSD and transmission electron microscopy (TEM). It was found that during the cooling process, after the steel is annealed, the athermal and ␣ martensites are formed. Tensile test results showed that the steel exhibits yield and tensile strength around 650 and 950 MPa with a total elongation around 45%. The austenite texture contains brass, copper and Goss components while the ␣ and martensites textures contain rotated cube and prismatic and pyramidal fibers, respectively.
“…This indicated that a possible martensitic transformation was also responsible by the deformation , in addition to twinning. The procedure for calculating the SFE has described in detail elsewhere 6 . Saeed-Akbari et al 7 calculated the SFE values for steels containing 10-35%Mn (wt%).…”
Steels containing high levels of Mn, Si and Al exhibit high plasticity when deformed, owing to twinning-induced plastitity (TWIP) and transformation-induced plasticity (TRIP) effects. In this study, we investigated the microstructural evolution of samples of samples of a 17%Mn steel subjected to war rolling at 700° and 800°C. We also studied the effects of the microstructure of the steel samples on their mechanical behavior. Using a mathematic model the stacking fault energy of the steel was estimated to be 14.5 mJ/m 2 . This value was indicative of a martensitic transformation. The presence of martensite and twinned austenite was verified using optical microscopy, scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD) analyses. The presence of austenite and ε-and α'-martensites was confirmed using X-ray diffraction (XRD) analyses and dilatometry. Increasing the rate of cold reduction resulted in the formation of a α'-martensite phase and a decrease in the volume fraction of the ε-martensite phase. The volume fractions of the various phases were measured by integrating the areas under the XRD peaks. The sample subjected to a cold-rolling reduction of 81% and a subsequent annealing treatment did not contain a α'-martensite phase, indicating that it was fully recrystallized. The Vickers microhardness of the samples increased with an increase in the cold-rolling reduction rate. However, the microhardness values of the cold-rolled samples decreased after the annealing treatment.
“…Gutierrez-Urrutia and D. Raabe 25 in their study of FeMnAlC steels, and many other researchers, reported a form of carbides at the grain boundaries in the sediments, the k-carbides (Fe, Mn) 3 AlC. 24,25 SEM images of the second phase are precipitated in the grain boundary (Fe,Mn) 3 AlC phase. This phase is reported in the austenite grain boundaries of FeMnAl steel with high carbon content after hot-rolling, and is deposited after an aging process.…”
Section: -23mentioning
confidence: 87%
“…Stability against the g ® e martensite transformation is usually considered to imply stability against the g ® a' martensite transformation since e martensite laths form as an intermediate phase. 8,24 The Diffraction Pattern is given in Figure 6.…”
This study was undertaken to investigate the microstructure and mechanical properties of hot rolled Fe-13Mn-0.2C-1Al-1Si TWIP steel. Tensile tests were carried out at different strain rates to determine the Portevin-Le Chatelier (PLC) effect during deformation. Subsequently, the samples were investigated by light microscopy and SEM. The sample microstructures revealed inhomogeneous dislocation zones, deformation twinning and twin-dislocation interactions. Consequently, the PLC effect during deformation was determined to be responsible for the excellent mechanical properties of the TWIP steel. Keywords: TWIP steel, mechanical properties, microstructure, Portevin Le Chatelier effect V {tudiji je bila preiskovana mikrostruktura in mehanske lastnosti vro~e valjanega Fe-13Mn-0.2C-1Al-1Si TWIP jekla. Natezni preizkusi so bili izvedeni pri razli~nih hitrostih obremenjevanja. Kot rezultat nateznega preizkusa je bil ugotovljen u~inek Portevin-Le Chatelier (PLC) med deformacijo. Vzorci so bili nato preiskani s svetlobnim mikroskopom in s SEM. Mikrostruktura vzorcev ka`e nehomogena podro~ja dislokacij, deformacijske dvoj~ke in interakcije dvoj~kov z dislokacijami. Ugotovljeno je, da so odli~ne mehanske lastnosti TWIP jekla posledica vpliva PLC med deformacijo.
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