Elevated-temperature mechanical stability and transformation behavior of retained austenite in a quenching and partitioning steel

Min, Junying; Hector, Louis G.; Zhang, Ling; Lin, Jianping; Carsley, John E.; Sun, Li

doi:10.1016/j.msea.2016.07.090

Cited by 48 publications

(14 citation statements)

References 25 publications

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“…Recent studies have mainly concerned the kinetics of SIMT at room deformation temperature [3,4,[6][7][8][9][10][13][14][15][16][17]. However, some results concerning the effectiveness of the TRIP effect at reduced and elevated deformation temperatures are available in the literature [22,23,[26][27][28][29][30]. Mukherjee et al [30] investigated the stability of the γ phase in Fe-0.4C-1.48Mn-0.49Si-0.96Al steel deformed at 20 and 150 • C. They noticed a slight decrease in ultimate tensile strength (UTS) for the higher deformation temperature.…”

Section: Introductionmentioning

confidence: 99%

“…Their microstructure consists of ferrite, bainite, and dispersed retained austenite of different morphologies [ 7 , 8 , 9 ]. The mechanical stability of the retained austenite is related to its resistance against strain-induced martensitic transformation depending on grain size [ 10 , 11 ], morphology [ 12 , 13 ], type of surrounding phases [ 14 , 15 ], stress state [ 16 , 17 ], strain rate [ 18 , 19 , 20 , 21 ], and also on the stacking fault energy (SFE) affected by the deformation temperature [ 13 , 22 , 23 , 24 , 25 , 26 ].…”

Section: Introductionmentioning

confidence: 99%

“…In both cases, some amount of heat is generated in the deformed sheets [ 27 , 28 ]. The stability of retained austenite gradually increases with increasing deformation temperature [ 23 , 26 , 29 , 30 ]. Thus, it is very important to assess the effectiveness of the SIMT at elevated deformation temperatures.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Elevated Deformation Temperatures on Microstructural and Tensile Behavior of Si-Al Alloyed TRIP-Aided Steel

Kozłowska

Grajcar

2020

Materials

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The influence of elevated deformation temperatures on the relationships between the microstructure and mechanical properties in a hot-rolled Si-Al-alloyed transformation-induced plasticity (TRIP)-aided steel was studied in a static tensile test. The morphological features of specimens deformed at the different temperatures were characterized by different microstructural techniques: optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM). An increase in the deformation temperature from 20 to 200 °C resulted in the reduced effectiveness of the TRIP effect, due to the increasing mechanical stability of the γ phase. The gradual transformation of retained austenite into martensite expressed by a progressive increase in the work hardening exponent (n) led to a beneficial balance of strength, uniform elongation and total elongation. The best product of UTS × TEl = 17,805 MPa% showed the sample deformed at 20 °C with a peak n value amounting to 0.3.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of Elevated Deformation Temperatures on Microstructural and Tensile Behavior of Si-Al Alloyed TRIP-Aided Steel

Kozłowska

Grajcar

2020

Materials

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“…Recently, a commercial third-generation AHHS processed with a quenching and partitioning (Q&P) heat treatment has been the subject of several studies aimed at understanding its mechanical properties and martensitic transformation. [3][4][5][6] The Q&P process increases carbon enrichment of the retained austenite for both ductility and strength enhancements. [7][8][9][10] With an as-received microstructure consisting (primarily) of ferrite (a), tempered martensite (a¢ T ), and retained austenite, this material has a 980 MPa tensile strength with 18% total elongation, making it attractive for automotive applications.…”

Section: Introductionmentioning

confidence: 99%

Nanoscale Solute Partitioning and Carbide Precipitation in a Multiphase TRIP Steel Analyzed by Atom Probe Tomography

Devaraj

Abu-Farha

et al. 2018

JOM

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Nanoscale solute partitioning across multiple constituent phases in a 980grade quenched and partitioned (Q&P) steel was analyzed using atom probe tomography (APT). The Q&P process was used to increase the C content in the retained austenite phase thereby improving its stability under plastic straining. Significant carbon enrichment of austenite was measured with decreased levels of C in martensite and almost depleted C content in ferrite, supporting the C partitioning mechanism in the literature. The APT analysis of retained austenite surrounded by martensite demonstrated a higher amount of C content compared with retained austenite surrounded by the ferrite phase. Lath and discrete carbide particle precipitation was also observed inside martensite colonies, tying up C and reducing the total amount of C available for austenite stabilization. In addition, the partitioning of Mn and other minor elements was quantitatively investigated by correlating APT and SEM-EBSD. These techniques provide a robust methodology for analyzing nanoscale compositional partitioning in multiphase steels, TRIP steels in particular, which can be used to better explain their microstructure-mechanical property relationships.

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“…No primeiro caso essa estabilidade, como tem sido comentado, é garantida, principalmente, pelo teor de carbono, que é um dos elementos fundamentais para estabilização da austenita [43]. No entanto, outros fatores também influenciam a estabilidade da austenita, como seu tamanho de grão, morfologia e orientação, propriedades das fases que a circundam e a temperatura e taxa de deformação [44][45][46][47][48]. Contudo, entre todos os fatores que estabilizam a austenita, o teor de carbono e o tamanho de grão são os dois mecanismos principais [35,48].…”

Section: Importância Justificativa E Desafios Para O Desenvolvimentounclassified

Análise numérica e experimental de um aço TRIP submetido aos processos de estampagem a quente e têmpera e partição (Q&P).

Echeverri¹

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The development of numerical and physical simulation methods has created new possibilities regarding the optimization of metal forming processes, taking into account real industrial forming processes. Therefore, by applying such methods of analysis it is now possible to assess the material phase transformations and predict the interactions between material properties and the forming process, the constitutive behavior of the material, and optimize process variables as well as predicting the best material-process-performance relationship. The increasing usage of Advanced High Strength Steels (AHSS) in automotive applications demands a better insight of the physical phenomena involved in the thermomechanical processing in order to optimize the performance of the final manufactured part. Thermomechanical simulation of the hot stamping, quenching and partitioning process was carried out in a Gleeble machine coupled to the XTMS Synchrotron X-ray diffraction line at the National Nanotechnology Laboratory (LNNano). Carbon partitioning, carbon contents, and amount of retained austenite, martensite, bainite and ferrite was assessed online during the experiments. In addition, characterization techniques by optical, electron microscopy (FEG-SEM and STEM), EBSD, and Atom Probe Tomography (APT) were applied. Mechanical testing of subsize specimens of the processed steels was performed by means of tensile tests and macro and nanoindentation tests. The numerical analysis was performed using the finite element method (FEM) and object-oriented finite element technique (OOF). The results were compared with the experimental results of mechanical testing of specimens used in the thermomechanical simulations and with hot stamped sheets, where quenching and partitioning were carried out. The results and conclusions obtained in this project allow the identification of the fundamental mechanisms of the process, helping the design of the hot stamping process for AHSS steels used primarily in the automotive industry, seeking weight reduction to improve fuel economy and increased passenger safety.

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Elevated-temperature mechanical stability and transformation behavior of retained austenite in a quenching and partitioning steel

Cited by 48 publications

References 25 publications

Effect of Elevated Deformation Temperatures on Microstructural and Tensile Behavior of Si-Al Alloyed TRIP-Aided Steel

Effect of Elevated Deformation Temperatures on Microstructural and Tensile Behavior of Si-Al Alloyed TRIP-Aided Steel

Nanoscale Solute Partitioning and Carbide Precipitation in a Multiphase TRIP Steel Analyzed by Atom Probe Tomography

Análise numérica e experimental de um aço TRIP submetido aos processos de estampagem a quente e têmpera e partição (Q&P).

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