Optimizing the Morphology and Stability of Retained Austenite in a δ-TRIP Steel

Yi, Hong; Chen, P.; Bhadeshia, H. K. D. H.

doi:10.1007/s11661-014-2267-4

Cited by 44 publications

(21 citation statements)

References 24 publications

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“…The similar result was also reported in Ref. [9] that much blocky austenite tended to form when annealed at a lower temperature. Table 2 lists the volume fractions of ferrite, bainite and retained austenite of experimental steel annealed at different temperatures.…”

Section: Microstructural Characterizationsupporting

confidence: 90%

Effect of annealing temperature on microstructure and mechanical properties of a high Al-low Si TRIP steel

Zhao

Chen

Yan

et al. 2015

MATEC Web of Conferences

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Abstract. By using optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), electron back scattered diffraction (EBSD) and tensile test, the effect of annealing temperature on microstructure and mechanical properties of a high Al-low Si TRIP steel was investigated. The results show that TRIP effect can be obtained when annealing temperature is above A c3 due to the existence of -ferrite in this high Al-low Si TRIP steel. That is to say, the microstructure consisting of ferrite, bainite and retained austenite can be obtained when annealing temperature is above A c3 . Furthermore, the tensile strength and the product of strength and elongation decrease with increasing annealing temperature when annealing temperature is above A c3 .

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Section: Microstructural Characterizationsupporting

confidence: 90%

Effect of annealing temperature on microstructure and mechanical properties of a high Al-low Si TRIP steel

Zhao

Chen

Yan

et al. 2015

MATEC Web of Conferences

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“…The mechanical stability of the lath ret is generally better than that of the blocky retained austenite [10]. Previo shown that the retained austenite with various mechanical stability in Q ducive to the continuous transformation of retained austenite [33][34][35], the the uniform elongation of steel. Third, a study by Sun et al [36] indicated angle between some lath ferrite/retained austenite and tensile direction.…”

Section: The Influence Of Microstructures On Uniform Elongations Of Q...mentioning

confidence: 99%

The Influence of Annealing Temperature on the Morphology of Structures and the Mechanical Properties of Prequenching—Quenching and Partitioning Steel

Cheng

Yang

et al. 2022

Materials

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In this study, we comparatively study the microstructures and mechanical properties of prequenching—quenching and partitioning (QQ&P) and traditional Q&P samples at different annealing temperatures (intercritical annealing temperatures). When the annealing temperature is 780 °C, the ferrite and retained austenite in QQ&P samples with lath and blocky morphologies. The lath retained austenite is mainly distributed along the lath ferrite. As the annealing temperature increases, the lath ferrite recrystallizes and gradually grows into the blocky (equiaxed) shape, leading to a decrease in the lath retained austenite content. When the annealing temperature increases to 870 °C, the ferrite content decreases significantly, and the retained austenite is mainly blocky and thin film, distributed at the boundaries of prior austenite grains and between martensite laths, respectively. Different from QQ&P samples, the ferrite and retained austenite in Q&P samples are mainly blocky when the annealing temperature is 780 °C or 810 °C. When the annealing temperature is increased to 870 °C, the microstructures of the Q&P sample are basically the same as that of the QQ&P sample. The 780 °C-QQ&P sample and the 810 °C-QQ&P sample have higher total elongation and product of strength and elongations (PSEs) than their counterpart Q&P samples due to the fact that lath ferrite and retained austenite are conducive to carbon diffusion and carbon homogenization in austenite grains, thereby improving the thermal stability and volume fraction of the retained austenite. In addition, the lath structures can release local stress concentration and delay the formation of voids and microcracks. The difference of mechanical properties between QQ&P samples and Q&P samples decreases with the increase in the annealing temperature. The results show that the low annealing temperature combined with prequenching—Q&P heat treatments can significantly improve the elongation and PSE of Q&P steel.

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“…As a result, when the holding time at IBT is short (2 minutes) in TR-1Mo-2t and TR-2Mo-2t, the lathshaped kind of bainitic ferrite may emerge. As a consequence, RA with lm morphology is found within the lath-shaped bainitic ferrite [31]. Figure 7.a2 and c clearly demonstrate them.…”

Section: Om and Fe-sem Analysismentioning

confidence: 79%

“…Yi et al [30] showed that the presence of Al up to 1.5 wt.% is a stabilizing element of the δ-ferrite, which contributes to excellent tensile properties, in all solid states. The production of bainite and δ-TRIP steels might potentially bene t from the addition of Al [23,30,31].…”

Section: Introductionmentioning

confidence: 99%

Analysis of the properties of 0.2C-4Al-1.2Mn TRIP-assisted Steel subjected to Mo micro-alloy and isothermal bainitic transformation (IBT) time

Gholambargani

Palizdar

Khanlarkhani

et al. 2023

Preprint

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In this investigation, the results of the experiment in which two samples of TRIP-assisted steel were micro-alloyed with 0.05 and 0.30 wt.% Mo addition in combination with isothermal bainitic transformation (IBT) time parameters was analyzed and evaluated. Microstructures were studied using optical microscope (OM) and field emission scanning electron microscope (FE-SEM) equipped with an energy dispersive X-ray spectrometer (EDX). Using X-ray diffraction (XRD), the retained austenite (RA) phase volume percentage was calculated. The studied steels had a multi-phased structure including δ-ferrite as the matrix phase and α-ferrite, bainite, and RA along with some martensite. The quantity of RA and its morphology in the microstructure of the samples are key factors in achieving desirable combinations of mechanical characteristics (high strength and acceptable ductility). Yield stresses of 400-440 MPa, tensile strengths of 790-870 MPa, and elongations to failure of 24-34% were observed in TRIP-assisted steels containing 0.05 and 0.30 wt.% Mo-alloy. It was determined that the best UTS×TE was (850MPa×32%) 27200 MPa.%, with 0.30 wt.% Mo addition and IBT temperature and time of 450 ℃ and 10 minutes.

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Optimizing the Morphology and Stability of Retained Austenite in a δ-TRIP Steel

Cited by 44 publications

References 24 publications

Effect of annealing temperature on microstructure and mechanical properties of a high Al-low Si TRIP steel

Effect of annealing temperature on microstructure and mechanical properties of a high Al-low Si TRIP steel

The Influence of Annealing Temperature on the Morphology of Structures and the Mechanical Properties of Prequenching—Quenching and Partitioning Steel

Analysis of the properties of 0.2C-4Al-1.2Mn TRIP-assisted Steel subjected to Mo micro-alloy and isothermal bainitic transformation (IBT) time

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