In Situ Studies of Intercritically Austempered Ductile Iron Using Neutron Diffraction

Druschitz, Alan P.; Aristizábal, Ricardo; Druschitz, Edward; Hubbard, Camden R.; Watkins, Thomas R.; Walker, Larry R; Ostrander, M

doi:10.1007/s11661-011-0921-7

Cited by 15 publications

(8 citation statements)

References 6 publications

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“…This would apply when partial reaustenitization is looked for as is the case for manufacturing so-called dual phase ADI. 12,13) • Upon cooling, the results showed that ferrite growth can start at very low undercooling with respect to Tα while pearlite needs some finite undercooling relative to Tp to appear. 14) For modelling the eutectoid transformation, it has been accepted that ferrite appears at the interface between austenite and graphite 15,16) giving rise to the bull-eye structure.…”

Section: Introductionmentioning

confidence: 98%

Critical Temperature Range in Standard and Ni-bearing Spheroidal Graphite Cast Irons

et al. 2012

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Describing the conditions for reaustenitization of spheroidal graphite cast irons is of interest for their heat-treatment after casting, e.g. for manufacturing austempered ductile irons. Differential thermal analysis has been used to characterize the direct eutectoid transformation and the reverse transformation, i.e. the reaustenitization. This has been applied to a standard and a Ni-bearing alloy, with a ferritic matrix for the former, both a ferritic and a pearlitic matrix for the latter. The results are discussed in relation with the stable and metastable three phase fields. While earlier description of the direct eutectoid transformation is confirmed, the one for reverse eutectoid has been found more complex and is amended.

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Section: Introductionmentioning

confidence: 98%

Critical Temperature Range in Standard and Ni-bearing Spheroidal Graphite Cast Irons

et al. 2012

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“…Since a new microstructure developed as a result of the novel double annealing, a detailed microstructural characterization using a neutron beam technique was proposed. It was found that neutron beam characterization gave good results in determining RS in ADI [22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

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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“…[1][2][3][4][5][6][7][8] In previous studies, DMS-ADI was named as dual-phase austempered ductile iron (DP-ADI) [9][10][11][12][13][14][15][16] , austempered ductile iron with dualmatrix structure (ADI with DMS) 1-3, 7, 8, 17, 18 , ductile cast iron with dual-matrix structure (DMS) 19,20 , dual-phase matrix austempered ductile iron (DPM-ADI) 21 , dual-matrix ductile iron (DM-DI) 22 , and intercritically austempered ductile iron (IADI). [23][24][25][26][27][28][29][30][31][32] The term dual-matrix structure was used first by Voigt et al in their study. 33 However, Wade&Ueada 34 first produced the dual-matrix structure in ductile irons and they had named it ductile cast iron with duplex matrix.…”

Section: Introductionmentioning

confidence: 99%

Effect of Austempering Times on the Microstructures and Mechanical Properties of Dual-Matrix Structure Austempered Ductile Iron (DMS-ADI)

et al. 2021

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In this study, the effect of the austempering times on the microstructures and mechanical properties of dual-matrix structure austempered ductile iron (DMS-ADI) was investigated. With this aim, unalloyed as-cast ductile iron tensile samples were austenitized at 810 °C for 30 min to intercritical austenitizing followed by austempering at 350°C for various austempering times (45 min to 180 min). Experimental results showed that dual-matrix structures consisting of proeutectoid ferrite ? ausferrite were obtained in austempered ductile iron from intercritical austenitizing temperatures. It was determined that as the austempering time increased, the ausferritic structure became considerably clear and its volume fraction was almost constant (45-47%) after 90 min of austempering time. The yield and tensile strength of the samples decreased and the total elongation and breaking energy increased with increasing austempering times, but after the 120-min austempering time, both the total elongation and breaking energy of the samples decreased. It was established that the austempering times had no significant effect on the morphology of ausferrite. The best mechanical properties were obtained between 70-and 130-minute austempering times that can be defined as the processing window. In addition, it was determined that the DMS-ADI had similar austempering kinetics with the ADI.

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In Situ Studies of Intercritically Austempered Ductile Iron Using Neutron Diffraction

Cited by 15 publications

References 6 publications

Critical Temperature Range in Standard and Ni-bearing Spheroidal Graphite Cast Irons

Critical Temperature Range in Standard and Ni-bearing Spheroidal Graphite Cast Irons

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

Effect of Austempering Times on the Microstructures and Mechanical Properties of Dual-Matrix Structure Austempered Ductile Iron (DMS-ADI)

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