Influence of Alloy Content and Prior Microstructure on Evolution of Secondary Phases in Weldments of 9Cr-Reduced Activation Ferritic-Martensitic Steel

Paul, V. Thomas; Sudha, C.; Saroja, S.

doi:10.1007/s11661-015-2954-9

Cited by 11 publications

(3 citation statements)

References 37 publications

(38 reference statements)

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“…Although yttrium addition improves the property of the RAFM steel [9,10], all of the previous studies have added Y 2 O 3 with an yttrium mass fraction exceeding 0.15wt-% to the ODS–RAFM steel. When present in excessive amounts, the yttrium segregates and many yttrium-rich blocks appear in the alloy.…”

Section: Introductionmentioning

confidence: 99%

Effects of yttrium on microstructure and properties of reduced activation ferritic-martensitic steel

Qiu

Zhan

et al. 2018

Materials Science and Technology

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This study investigates the inclusions, microstructure, tensile properties, and impact toughness of reduced activation ferritic/martensitic (RAFM) steels with different Y contents (0.006, 0.034 and 0.071 wt-%). Owing to the pinning of the grain boundary to the Y inclusions (which refines the original austenite grain size) and an existing Fe–Cr–Ta–Y–S–O phase, the tensile strength at both room and high temperatures increased with increasing Y content (below 0.071%). Increasing the Y content to 0.034 wt-% decreased the ductile-to-brittle transition temperature (DBTT). However, when the Y content reached 0.071 wt-%, the DBTT increased as the Y precipitated into blocky yttrium-rich inclusions. The microstructure, tensile properties, and impact toughness of the RAFM steel were optimised at a Y content of approximately 0.034 wt-%.

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Section: Introductionmentioning

confidence: 99%

Effects of yttrium on microstructure and properties of reduced activation ferritic-martensitic steel

Qiu

Zhan

et al. 2018

Materials Science and Technology

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“…The dissolution of pre-existing carbides precipitates occurs as the soaking temperature is increased above Ac 3 leading to enhanced enrichment of the austenite matrix with alloying elements which would decrease the M S temperature resulting in the formation of fine martensite laths with the higher amount of dislocation density [154]. Paul et al [159] have already studied the accelerated kinetics in terms of enhanced precipitation of carbides at lath/grain boundaries during ageing treatment of 9Cr-RAFM steel.…”

Section: Microstructurementioning

confidence: 99%

Fractographic correlations with mechanical properties in ferritic martensitic steels

Das¹,

Chakravartty²

2017

Surf. Topogr.: Metrol. Prop.

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The ultimate continuum of a material is nothing but the process called fracture. Fracture surface retains the imprint of the entire deformation history undergone in a material. Hence, it is possible to derive the approximate deformation and fracture properties of a material from a systematic fracture feature analysis. There has been large volume of literature available in the open domain correlating different mechanical and fracture responses of reduced activation ferritic martensitic grade steels under various testing conditions/circumstances with corresponding microstructural interpretation. There has been no such literature available to establish the relationship between the two-dimensional fracture geometry/topography with its corresponding deformation and mechanical properties of the material as a function of testing temperature, which has been the primary aim in the current investigation. A comprehensive literature survey has been carried out to realize this fact. In order to establish the above hypothesis, many tensile experiments were carried out at constant strain rate by systematic variation of the test temperature. The initial void volume fraction or the inclusion content of material was kept unaltered and the test temperature has been varied orderly on different multiple specimens to vary the deformation-induced nucleation sites of micro voids (i.e. different carbides, phase interfaces, dislocation pile up etc), which results in a change of fracture topography under uniaxial tensile deformation. A conventional metallographic technique followed by optical microscopy has been employed to understand the basic morphologies and characteristics of the alloy exposed at different temperatures. Fractographic investigation of the broken tensile specimens at various temperatures is carried out to measure the fracture features by using quantitative fractography on representative scanning electron fractographs through image processing.

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“…A detailed description of the HAZ (region V) of RAFM steel consisting of CGHAZ and FGHAZ has also been given elsewhere. [10] Detailed characterization of regions II, III, and IV will be described in the following sections.…”

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confidence: 99%

Microstructural Variations Across a Dissimilar 316L Austenitic: 9Cr Reduced Activation Ferritic Martensitic Steel Weld Joint

Paul

Karthikeyan

Dasgupta

et al. 2015

Metall Mater Trans A

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This paper discuss the microstructural variations across a dissimilar weld joint between SS316 and 9Cr-RAFM steel and its modifications on post weld heat treatments (PWHT). Detailed characterization showed a mixed microstructure of austenite and martensite in the weld which is in agreement with the phases predicted using Schaeffler diagram based on composition measurements. The presence of very low volume fraction of d-ferrite in SS316L has been identified employing state of the art electron back-scattered diffraction technique. PWHT of the ferritic steel did not reduce the hardness in the weld metal. Thermal exposure at 973 K (700°C) showed a progressive reduction in hardness of weld joint with duration of treatment except in austenitic base metal. However, diffusion annealing at 1073 K (800°C) for 100 hours resulted in an unexpected increase in hardness of weld metal, which is a manifestation of the dilution effects and enrichment of Ni on the transformation characteristics of the weld zone. Migration of carbon from ferritic steel aided the precipitation of fine carbides in the austenitic base metal on annealing at 973 K (700°C); but enhanced diffusion at 1073 K (880°C) resulted in coarsening of carbides and thereby reduction of hardness.

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Influence of Alloy Content and Prior Microstructure on Evolution of Secondary Phases in Weldments of 9Cr-Reduced Activation Ferritic-Martensitic Steel

Cited by 11 publications

References 37 publications

Effects of yttrium on microstructure and properties of reduced activation ferritic-martensitic steel

Effects of yttrium on microstructure and properties of reduced activation ferritic-martensitic steel

Fractographic correlations with mechanical properties in ferritic martensitic steels

Microstructural Variations Across a Dissimilar 316L Austenitic: 9Cr Reduced Activation Ferritic Martensitic Steel Weld Joint

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