Strain Induced Martensitic Transformation in Austempered Ductile Iron (ADI)

Li, Xiaohu; Saal, Patrick; Gan, Weimin; Landesberger, Martin; Hoelzel, Markus; Hofmann, M.

doi:10.1088/1742-6596/746/1/012055

Cited by 5 publications

(4 citation statements)

References 22 publications

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“…Additionally, in the SADP, a typical crystallographic orientation relationship ([001]F//[011]A), labeled as Nishiyama-Wasserman (N-W)) between austenite and ferrite has been found and is depicted in Figure 2b. This also is in good agreement with recent texture measurements showing a similar orientation relationship in bulk samples [28,29].…”

Section: Ausferritic Microstructuresupporting

confidence: 93%

Carbon Redistribution Process in Austempered Ductile Iron (ADI) During Heat Treatment—APT and Synchrotron Diffraction Study

Wagner

Stark

et al. 2019

Metals

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In-situ synchrotron diffraction and atom probe tomography (APT) have been used to study the carbon diffusion and redistribution process in austempered ductile iron (ADI) during austempering. The process of carbon content change in bainitic ferrite during different austempering temperatures has been determined quantitatively. The transformation in ADI is controlled by decarburization of supersaturated ferrite and carbide precipitation and has been found to be divided into three stages based on a model developed for bainitic steels by Takahashi and Bhadeshia. The formation, morphology and composition of carbides and carbon clusters in ferrite after austempering have been identified unequivocally by APT. Finally, the relationships of carbon content in ferrite, carbon gap values, and austempering temperatures in the ADI alloy were expressed using empirical equations.

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Section: Ausferritic Microstructuresupporting

confidence: 93%

Carbon Redistribution Process in Austempered Ductile Iron (ADI) During Heat Treatment—APT and Synchrotron Diffraction Study

Wagner

Stark

et al. 2019

Metals

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“…Before and after, no significant deviation from a single Gaussian peak occurred. This indicates that the trends can be correctly approximated using a single Gaussian function, which we therefore kept for comparability to former results [ 10 , 47 ].…”

Section: Resultsmentioning

confidence: 80%

Phase Transition Kinetics in Austempered Ductile Iron (ADI) with Regard to Mo Content

et al. 2020

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The phase transformation to ausferrite during austempered ductile iron (ADI) heat treatment can be significantly influenced by the alloying element Mo. Utilizing neutron diffraction, the phase transformation from austenite to ausferrite was monitored in-situ during the heat treatment. In addition to the phase volume fractions, the carbon enrichment of retained austenite was investigated. The results from neutron diffraction were compared to the macroscopic length change from dilatometer measurements. They show that the dilatometer data are only of limited use for the investigation of ausferrite formation. However, they allow deriving the time of maximum carbon accumulation in the retained austenite. In addition, the transformation of austenite during ausferritization was investigated using metallographic methods. Finally, the distribution of the alloying elements in the vicinity of the austenite/ferrite interface zone was shown by atom probe tomography (APT) measurements. C and Mn were enriched within the interface, while Si concentration was reduced. The Mo concentration in ferrite, interface and austentite stayed at the same level. The delay of austenite decay during Stage II reaction caused by Mo was studied in detail at 400 °C for the initial material as well as for 0.25 mass % and 0.50 mass % Mo additions.

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“…The metallographic examination of the specimens followed by tempering again showed that the material is isotropic and the metallography of all specimens is uniform. Spheroidal graphite and the ausferrite phase of the ADI alloy can be seen in the metallographic images [28]. The isotropic nature of the material and its uniformity over the entire cross-section are visible.…”

Section: Microstructurementioning

confidence: 91%

Influence of a Novel Double Tempering Process on the Microstructure and Mechanical Properties of Cu-Alloyed Austempered Ductile Iron with Possible Nano (Micro)-Characterization Using Neutron Beam Techniques

Čatipović,

Rogante,

Avdušinović

et al. 2023

Crystals

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In this paper, a novel method for the double heat treatment of ductile iron was applied. Ten sets of specimens (three specimens in each set) of ductile cast iron (DCI) containing 0.51% wt. Cu were prepared and converted to austenitic ductile iron. All specimens were austenitized at 850 °C for 60 min and annealed at 420 °C, 331 °C and 250 °C for 120, 68 and 30 min, respectively. Five sets of samples were then annealed at 500 °C for 60 min, creating a novel double heat treatment process for annealing. Finally, all specimens were slowly cooled in air at ambient temperature. Tensile strength, hardness and elongation were measured in all specimens to compare the specimens with and without subsequent tempering. A microstructural analysis was also performed, which showed that the microstructure changed for the specimens that were subsequently tempered with. The results show that specimens with subsequent tempering have slightly higher hardness, a small decrease in tensile strength and significantly higher elongation. In addition, specimens with subsequent tempering exhibit more uniform mechanical properties compared to specimens without subsequent tempering. The use of neutron beam techniques was proposed to further characterize the newly formed microstructure after subsequent tempering.

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Strain Induced Martensitic Transformation in Austempered Ductile Iron (ADI)

Cited by 5 publications

References 22 publications

Carbon Redistribution Process in Austempered Ductile Iron (ADI) During Heat Treatment—APT and Synchrotron Diffraction Study

Carbon Redistribution Process in Austempered Ductile Iron (ADI) During Heat Treatment—APT and Synchrotron Diffraction Study

Phase Transition Kinetics in Austempered Ductile Iron (ADI) with Regard to Mo Content

Influence of a Novel Double Tempering Process on the Microstructure and Mechanical Properties of Cu-Alloyed Austempered Ductile Iron with Possible Nano (Micro)-Characterization Using Neutron Beam Techniques

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