Enhancement of Impact Toughness Via Tailoring Deformation Compatibility of Constituent Phases in Duplex Q&amp;P Steel with Excellent Strength and Ductility

Du, Hao; Gong, Yu; Liang, Tu; Li, Yu; Xu, Yuantao; Lu, Xianwen; Zeng, Qiaoshi; Jin, Xuejun

doi:10.1007/s11661-020-05701-8

Cited by 25 publications

(3 citation statements)

References 96 publications

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“…The microvoids are often nucleated near the RA films in the M/A constituents; meanwhile, there is no clear evidence of void or crack initiation at the grain boundaries or transition carbides. This is in accordance with the findings of Du et al, who reported that the deformation incompatibility between RA and tempered martensite leads to the preferential formation of voids and microcracks [ 52 ]. The straight propagation path of the secondary crack through the bainitic ferrite grain shown in Figure 15 c also indicates that the coarse islands of RA cannot effectively inhibit crack growth.…”

Section: Discussionsupporting

confidence: 93%

Strength–Toughness of a Low-Alloy 0.25C Steel Treated by Q&P Processing

et al. 2023

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Quenching and partitioning (Q&P) treatments were applied to 0.25C steel to produce the microstructures that exhibit an improved balance of mechanical properties. The simultaneous bainitic transformation and carbon enrichment of retained austenite (RA) during the partitioning stage at 350 °C result in the coexistence of RA islands with irregular shapes embedded in bainitic ferrite and film-like RA in the martensitic matrix. The decomposition of coarse RA islands and the tempering of primary martensite during partitioning is accompanied by a decrease in the dislocation density and the precipitation/growth of η-carbide in the lath interiors of primary martensite. The best combinations of a yield strength above 1200 MPa and an impact toughness of about 100 J were obtained in the steel samples quenched to 210–230 °C and subjected to partitioning at 350 °C for 100–600 s. A detailed analysis of the microstructures and the mechanical properties of the steel subjected to Q&P, water quenching, and isothermal treatment revealed that the ideal strength–toughness combinations could be attributed to the mixture of the tempered lath martensite with finely dispersed and stabilized RA and the particles of η-carbide located in the lath interiors.

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Section: Discussionsupporting

confidence: 93%

Strength–Toughness of a Low-Alloy 0.25C Steel Treated by Q&P Processing

et al. 2023

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“…Hot-rolling schedules were previously described elsewhere. [33,34] Square specimens with a thickness of 3 mm were cut from the as-received slab by wire-cut electrical discharge machining. These square specimens were first austenitized at 730 °C for 30 minutes and subsequently quenched in liquid nitrogen (À 196 °C) for 5 h followed by intercritical annealing treatment at 600 °C for 30 minutes.…”

Section: A Materials Treatment and Microstructural Characterizationmentioning

confidence: 99%

Interpretation of Dynamic Strain Aging in an Intercritical Annealed Steel by Dislocation Multiplication Induced by Martensitic Transformation

Gong

Zeng

et al. 2021

Metall Mater Trans A

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To elucidate the dynamic strain aging (DSA) mechanism that causes serrated flow in the tensile curves of an intercritical annealed steel with retained austenite (RA) and intercritical ferrite, the multi-aspect microstructural characterization and micromechanical deformation behavior were systematically investigated in this study. Our results demonstrate that the DSA phenomenon is dependent on the strain rate, deformation temperature, and strain. This is accompanied by deformation-induced martensitic transformation (DIMT) and the generation of crystallographic defects in nucleating and propagating Portevin-Le Chatelier bands. An increase in the deformation temperature and strain rate leads to an increase in the stacking fault energy of RA. This inhibits the growth of martensitic embryos and retards the kinetics of martensitic transformation of RA, consequently decreasing or suppressing the DSA phenomenon. Furthermore, neither the long-range diffusion model of carbon atoms nor the short-range diffusion model on the reorientation of C-Mn complexes could reasonably explain the DSA phenomenon in this study. Based on the in situ synchrotron X-ray diffraction results and established mathematical models stemming from the dislocation multiplication theory, the DSA could be attributed to the periodic instantaneous dislocation multiplication in constituent phases caused by burst DIMT.

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“…Other HS materials include the precipitates, second phase, and multilevel grain and multiphase microstructures. [20][21][22][23][24][25][26][27] Tailoring microstructural heterogeneity is needed to enhance the synergistic effect in HS materials. [1][2][3][4][5][6][7][8][9][10] Nanoscale grains produce high strength but low ductility, while coarse grains do the opposite.…”

Section: Introductionmentioning

confidence: 99%

Gradient and lamellar heterostructures for superior mechanical properties

Zhu

2021

MRS Bulletin

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Heterostructured (HS) materials are a novel class of materials with mechanical properties that are superior over their conventional homogeneous counterparts. They are composed of HS zones with a dramatic difference in mechanical behaviors, which produces a synergistic effect on mechanical properties that are above the prediction by the rule-of-mixtures. Among all heterostructures, the two most studied are grain-size gradient structure and heterolamellar structure. These two heterostructures produce typical heterogeneous deformation during tensile deformation, producing long-range back stress in the soft zones and forward stress in the hard zones, which collectively produces hetero deformation-induced (HDI) stress to enhance the yield strength before yielding, and HDI hardening after yielding to retain ductility. In this article, we will focus on these two types of heterostructures. The issues, concerns, and progress are reviewed with the emphasis on the synergistic effect of mechanical properties, the fundamentals of several special plastic behaviors (e.g., strain gradient, HDI hardening and strain hardening), the plastic deformation mechanism, and the relationship between the microstructure and properties.

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Enhancement of Impact Toughness Via Tailoring Deformation Compatibility of Constituent Phases in Duplex Q&P Steel with Excellent Strength and Ductility

Cited by 25 publications

References 96 publications

Strength–Toughness of a Low-Alloy 0.25C Steel Treated by Q&P Processing

Strength–Toughness of a Low-Alloy 0.25C Steel Treated by Q&P Processing

Interpretation of Dynamic Strain Aging in an Intercritical Annealed Steel by Dislocation Multiplication Induced by Martensitic Transformation

Gradient and lamellar heterostructures for superior mechanical properties

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