High-throughput investigation of processing–microstructure relation in quenching and partitioning steels via gradient heat treatment and rapid characterization

Abstract

This study presents a new high-throughput method to investigate the relationship between the quenching temperature (QT) and microstructure in quenching and partitioning (Q&P) steels produced by “one-step” Q&P treatment. This approach involves a gradient heat treatment, in which a rod sample is quenched and then a significant temperature gradient is established along the rod for isothermal holding, allowing the exploration of QT from 457 to 280°C in a single heat treatment. Synchrotron X-ray diffraction and high-speed nanoindentation mapping were used to efficiently measure phase fractions and the carbon content in retained austenite (RA) across different QTs. The results show that as QT decreases, a larger fraction of austenite transforms into martensite and bainite during isothermal holding, leading to increased carbon enrichment in the untransformed austenite. The volume fraction of RA initially increases with decreasing QT due to carbon enrichment, then decreases as the untransformed austenite fraction reduces after isothermal holding. The experimental results are compared to the predictions by thermodynamic models, which tend to overestimate the kinetics of phase transformation and carbon partitioning, emphasizing the importance of high-throughput experimental validation.

Keywords

gradient heat treatment / high-throughput / nanoindentation / quenching and partitioning steel / synchrotron X-ray diffraction

References

[1] Speer JG, Edmonds DV, Rizzo FC, Matlock DK. Partitioning of carbon from supersaturated plates of ferrite, with application to steel processing and fundamentals of the bainite transformation. Curr Opin Solid State Mater Sci. 2004; 8(3–4): 219-237.

[2] Speer J, Matlock DK, De Cooman BC, Schroth JG. Carbon partitioning into austenite after martensite transformation. Acta Mater. 2003; 51(9): 2611-2622.

[3] Kumar S. Quenching and partitioning (Q&P) process: a critical review of the competing reactions. Mater Sci Technol. 2022; 38(11): 663-675.

[4] Chen S, Wang C, Shan L, Li Y, Zhao X, Xu W. Revealing the conditions of bainitic transformation in quenching and partitioning steels. Metall Mater Trans A. 2019; 50(9): 4037-4046.

[5] Gui X, Gao G, Guo H, Zhao F, Tan Z, Bai B. Effect of bainitic transformation during BQ&P process on the mechanical properties in an ultrahigh strength Mn-Si-Cr-C steel. Mater Sci Eng A. 2017; 684: 598-605.

[6] Yan S, Liu X, Liu WJ, Lan H, Wu H. Comparison on mechanical properties and microstructure of a C–Mn–Si steel treated by quenching and partitioning (Q&P) and quenching and tempering (Q&T) processes. Mater Sci Eng A. 2015; 620: 58-66.

[7] Kumar S, Singh SB. Quenching and partitioning (Q&P) steel: alloy design, phase transformation and evolution of microstructure. Metall Mater Trans A. 2023; 54(8): 3134-3156.

[8] Dong XX, Shen YF, Jia N, Zhu YT. Improving mechanical properties and retained-austenite stability of a medium carbon Q&P steel by adjusting phase ratio. Mater Sci Eng A. 2022; 833:142580.

[9] Seo EJ, Cho L, De Cooman BC. Application of quenching and partitioning (Q&P) processing to press hardening steel. Metall Mater Trans A. 2014; 45: 4022-4037.

[10] Seo EJ, Cho L, Estrin Y, De Cooman BC. Microstructure-mechanical properties relationships for quenching and partitioning (Q&P) processed steel. Acta Mater. 2016; 113: 124-139.

[11] Clarke AJ, Speer JG, Miller MK, et al. Carbon partitioning to austenite from martensite or bainite during the quench and partition (Q&P) process: a critical assessment. Acta Mater. 2008; 56(1): 16-22.

[12] Kumar S, Singh SB. Microstructure-property relationship in the quenching and partitioning (Q&P) steel. Mater Char. 2023; 196:112561.

[13] Wang Y, Xu Y, Zhang T, Li J, Hou X, Sun W. Effects of quenching temperature on bainite transformation, retained austenite and mechanical properties of hot-galvanized Q&P steel. Mater Sci Eng A. 2021; 822:141643.

[14] Carpio M, Calvo J, García O, Pedraza JP, Cabrera JM. Heat treatment design for a QP steel: effect of partitioning temperature. Metals. 2021; 11(7):1136.

[15] Ebner S, Suppan C, Stark A, Schnitzer R, Hofer C. Austenite decomposition and carbon partitioning during quenching and partitioning heat treatments studied via in-situ X-ray diffraction. Mater Des. 2019; 178:107862.

[16] Edmonds DV, He K, Rizzo FC, De Cooman BC, Matlock DK, Speer JG. Quenching and partitioning martensite—a novel steel heat treatment. Mater Sci Eng A. 2006; 438–440: 25-34.

[17] Liu L, He BB, Cheng GJ, Yen HW, Huang MX. Optimum properties of quenching and partitioning steels achieved by balancing fraction and stability of retained austenite. Scr Mater. 2018; 150: 1-6.

[18] Zhao Y, Sargent N, Li K, Xiong W. A new high-throughput method using additive manufacturing for alloy design and heat treatment optimization. Materialia. 2020; 13:100835.

[19] Wei M, Zhao L, Jiang L, Yang L, Wang H. Development of high-throughput rapid heat-treatment and characterization process. Acta Mater. 2023; 261:119365.

[20] Pashangeh S, Somani M, Banadkouki SSG. Microstructural evolution in a high-silicon medium carbon steel following quenching and isothermal holding above and below the M_s temperature. J Mater Res Technol. 2020; 9(3): 3438-3446.

[21] Wang Z, Huang MX. Optimising the strength-ductility-toughness combination in ultra-high strength quenching and partitioning steels by tailoring martensite matrix and retained austenite. Int J Plast. 2020; 134:102851.

[22] Allain S, Geandier G, Hell J-C, Soler M, Danoix F, Gouné M. Effects of Q&P processing conditions on austenite carbon enrichment studied by in situ high-energy X-ray diffraction experiments. Metals. 2017; 7(7):232.

[23] Stainless Structurals Special Profiles in Steel. Comparing the thermal conductivity of stainless steel to other metals. Accessed August 26, 2020. https://www.stainless-structurals.com/blog/comparing-the-thermal-conductivity-of-stainless-steel-to-other-metals/

[24] Liu Y-J, Tian J-Y, Liu M, Gan X-L, Liu S, Xu G. Effect of isothermal martensite and bainite transformation on microstructure and properties in a medium-carbon high-strength Q&P steel. J Iron Steel Res Int. 2024; 31(12): 3095-3108.

[25] Zhao J, Zhao X, Zhao X, Dong C, Kang S. Effects of nucleation site and morphology of carbide-free bainite on microstructures and properties of bainite/martensite multi-phase steels. Mater Sci Eng A. 2019; 744: 86-93.

[26] Van Dijk NH, Butt AM, Zhao L, et al. Thermal stability of retained austenite in TRIP steels studied by synchrotron X-ray diffraction during cooling. Acta Mater. 2005; 53(20): 5439-5447.

[27] Li YZ, Liang ZY, Huang MX. Strengthening contributions of dislocations and twins in warm-rolled TWIP steels. Int J Plast. 2022; 150:103198.

[28] Ungár T, Dragomir I, Révész Á, Borbély A. The contrast factors of dislocations in cubic crystals: the dislocation model of strain anisotropy in practice. J Appl Crystallogr. 1999; 32(5): 992-1002.

[29] Harjo S, Kawasaki T, Tomota Y, et al. Work hardening, dislocation structure, and load partitioning in lath martensite determined by in situ neutron diffraction line profile analysis. Metall Mater Trans A. 2017; 48(9): 4080-4092.

[30] Samanta S, Das S, Chakrabarti D, Samajdar I, Singh SB, Haldar A. Development of multiphase microstructure with bainite, martensite, and retained austenite in a co-containing steel through quenching and partitioning (Q&P) treatment. Metall Mater Trans A. 2013; 44: 5653-5664.

[31] Toji Y, Matsuda H, Herbig M, Choi P-P, Raabe D. Atomic-scale analysis of carbon partitioning between martensite and austenite by atom probe tomography and correlative transmission electron microscopy. Acta Mater. 2014; 65: 215-228.

[32] Zhou S, Hu F, Wang K, et al. A study of deformation behavior and stability of retained austenite in carbide-free bainitic steel during nanoindentation process. J Mater Res Technol. 2022; 20: 2221-2234.

[33] Yu X-P, Wu H-B, Gu Y, Yuan R, Zhang Y-Y, Feng Y-H. Effect of prior martensite on bainite transformation and microstructure of high-carbon nano-bainitic steel. J Iron Steel Res Int. 2022; 29(4): 647-654.

[34] He SH, He BB, Zhu KY, Huang MX. On the correlation among dislocation density, lath thickness and yield stress of bainite. Acta Mater. 2017; 135: 382-389.

[35] Yang G, Xia SL, Zhang FC, et al. Effect of tempering temperature on monotonic and low-cycle fatigue properties of a new low-carbon martensitic steel. Mater Sci Eng A. 2021; 826:141939.

[36] Koistinen DP, Marburger RE. A general equation prescribing the extent of the austenite-martensite transformation in pure iron-carbon alloys and plain carbon steels. Acta Metall. 1959; 7(1): 59-60.

[37] Li Y, Martín DS, Wang J, Wang C, Xu W. A review of the thermal stability of metastable austenite in steels: martensite formation. J Mater Sci Technol. 2021; 91: 200-214.

[38] Gong W, Tomota Y, Harjo S, Su YH, Aizawa K. Effect of prior martensite on bainite transformation in nanobainite steel. Acta Mater. 2015; 85: 243-249.

[39] Li Y, Chen S, Wang C, Martín DS, Xu W. Modeling retained austenite in Q&P steels accounting for the bainitic transformation and correction of its mismatch on optimal conditions. Acta Mater. 2020; 188: 528-538.

[40] Dai Z, Yang Z, Zhang C, Chen H. Incomplete carbon partitioning during quenching and partitioning of Fe-C-Mn-Si steels: modeling and experimental validations. Acta Mater. 2020; 200: 597-607.

[41] Dai Z, Chen H, Ding R, et al. Fundamentals and application of solid-state phase transformations for advanced high strength steels containing metastable retained austenite. Mater Sci Eng R. 2021; 143:100590.

[42] Cahn JW. The impurity-drag effect in grain boundary motion. Acta Metall. 1962; 10(9): 789-798.

[43] Hillert M. Solute drag in grain boundary migration and phase transformations. Acta Mater. 2004; 52(18): 5289-5293.

[44] Hosseini N, Forouzan F, Vuorinen E. In-situ microstructural evolution during quenching and partitioning of a high-carbon steel by high-temperature X-Ray Diffraction. Mater Today Commun. 2022; 31:103503.

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