Coherent to incoherent transition of precipitates during rupture test in TP347H austenitic stainless steels

Hong, Chang-Whan; Heo, Yoon-Uk; Heo, N. H.; Kim, Sung–Joon

doi:10.1016/j.matchar.2016.03.018

Cited by 20 publications

(2 citation statements)

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“…The lattice parameters of crystal structure is about 3.5877 Å as resulted from sintering at 900 o C and 3.5876 Å as resulted from sintering at 950C. These measurements are in agreement with some previous studies [8], [20]- [22] in determining the matrix of austenitic stainless steels and superalloys. In the basis of composition and electron diffraction patterns, fine particles of FeNiCr compounds that are evenly distributed in the interior and boundaries of austenite grains as reported by Dani et al [20] are particles containing high Cr, known as a'-Cr phase.…”

Section: Resultssupporting

confidence: 91%

Effect of Temperature of Spark Plasma Sintering on the Development of Oxide Compound in Fe-25wt%Ni-17wt%CrAustenitic Stainless Steel

2020

IJETER

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To investigate the effect of sintering temperature of spark plasma on the development of oxide compound in Fe-25wt%Ni-17wt%Cr austenitic stainless steels (ASS).The ingredient samples were high purity powder of Fe, Ni and Cr and mixed by through milling process for 5 hours. Compacting the three elements under 30MPa and vacuum was carried out in a spark plasma sintering (SPS) machine at temperature of 900 and 950 o C for 5 minutes. The microstructure of Fe-25wt%Ni-17wt%Cr ASS including oxide compound layer was examined through an Optical Microscope (OM), a Scanning Electron Microscope (SEM) and a Transmission Electron Microscope (TEM) equipped with Energy Dispersive Spectrometers (EDS), and also by Raman Spectroscopy.The crystal structure of austenite grains in the matrix was identified using X-Ray Diffractometer. Although, the SPS can consolidate nano alloy, the Fe-25wt%Ni-17wt%Cr ASS consists of matrix of fine austenite, g-FeNi grains and particles of a'-Cr. Sintering temperature at 950 o C increase O content in the surface of Fe-25wt%Ni-17wt%Cr ASS that mainly related to increasing the distribution of very fine a'-Cr particles as CrO compound beside of increasing the trapped air bubbles. The Raman spectra of Cr-rich M 2 O 3 was identified (M: Metal) at sintering temperature of 950 o C, while the Fe-rich M 2 O 3 and pure Fe 3 O 4 without significant amount of dissolved chromium or nickel in a main band at 671 cm −1 was identified at 900 o C. The existence of g-Fe 2 O 3 and a-Fe 2 O 3 was also successfully detected from the Raman.Changes in the number of particles with high Cr content or a'-Cr in the matrix with fine grains of g-FeNi formed during the process of sintering by spark plasma makes more oxide compounds in the Fe-25Ni-17Cr ASS at 950C as compared to sintering temperature at 900 o C. The oxide compound is formed from the reaction of O and Cr content in a'-Cr particles during process of spark plasma sintering.

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Section: Resultssupporting

confidence: 91%

Effect of Temperature of Spark Plasma Sintering on the Development of Oxide Compound in Fe-25wt%Ni-17wt%CrAustenitic Stainless Steel

2020

IJETER

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“…Both patterns also have sharp peaks, which indicates that crystals are formed perfectly in the austenite matrix of Fe-25Ni-17Cr ASS. Some studies about austenitic stainless steels and superalloys [15][16][17][18] have reported the lattice parameters of austenite matrix close to the results of this study. Sintering using SPS on the Fe-17Cr-25Ni ASS formed particles with a distribution as shown in Figure 2.a for temperature of 900°C and Figure 2.b for temperature of 950°C.…”

Section: Resultssupporting

confidence: 88%

Effect of Spark Plasma Sintering (SPS) at Temperatures of 900 and 950oc for 5 Minutes on Microstructural Formation of Fe-25Ni-17Cr Austenitic Stainless Steel

Dani¹

2020

IJETER

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This research is related to fabricate Fe-25Ni-17Cr austenitic stainless steel. Methodology: Fe-25Ni-17Cr austenitic stainless steel were made by spark plasma sintering at 900 and 950 o C for 5 minutes. Results: The microstructure of both the steels sintered at 900 and 950°C consists of particles with high Cr content, a'-Cr and austenite matrix containing of fine grains of g-FeNi.Sintering at high temperatures causes the fine grains to be seen more clearly. The fine grains of g-FeNi are twin grains that contain defects such as dislocations, stacking faults and trapped air bubbles. The defects are formed during the mixing process through milling and compacting under a 30 MPa load during the sintering process. The density of the first two defects decreased with increasing the sintering temperature. By contrast, more trapped air bubbles were noticed as increasing the sintering temperature and the distribution of fine a'-Fe particles higher. Since beside of higher the density of steel sintered at the high temperature, smaller grain size of austenite matrix and higher distribution of fine a'-Fe in the austenite matrix, the hardness of this steel is greater than the steel sintered at temperature of 900 o C. Applications/Originality/Value: This study fabricated austenitic stainless steel made from powders of 58% Fe, 25% Ni and 17% Cr. The manufacturing process is carried out through a sintering by spark plasma at temperatures of 900 and 950C for 5 minutes. The microstructure of austenitic stainless steel that formed very well at 950C consisted of very fine grains of austenite g-FeNi and a'-Fe particles were distributed throughout the g-FeNi grains, resulting in a high hardness of 399.3 HV 0.2 .

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Effects of Typical Inclusions on the As‐Cast Microstructure and Recrystallization of Low‐Density Steel

Guo,

Zhu,

Wang

et al. 2024

steel research int.

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Herein, the effect of nonmetallic inclusions (NMIs) on the microstructure and dynamic recrystallization (DRX) of Fe–23Mn–6Al–0.7C low‐density steel is studied. The specimens are separately added sulfur (S) and nitrogen (N) to change the characteristics of NMIs. As a result, the addition of S significantly increases the number of MnS inclusions and AlN–MnS complex inclusions in low‐density steel. The addition of N results in a significant increase in the size of NMIs. In the results, NMIs act as the heterogeneous nucleation sites for austenite and refine the as‐cast grains in low‐density steel. In addition, the treated specimens are subjected to a thermal compression simulation experiment. During the thermal compression process, discontinuous DRX is considered to be the main recrystallization method in the experimental low‐density steels. Meanwhile, the typical NMIs significantly accelerate the DRX within grains in low‐density steel through the mechanism of particle‐stimulated nucleation and continuous DRX.

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Coherent to incoherent transition of precipitates during rupture test in TP347H austenitic stainless steels

Cited by 20 publications

References 31 publications

Effect of Temperature of Spark Plasma Sintering on the Development of Oxide Compound in Fe-25wt%Ni-17wt%CrAustenitic Stainless Steel

Effect of Temperature of Spark Plasma Sintering on the Development of Oxide Compound in Fe-25wt%Ni-17wt%CrAustenitic Stainless Steel

Effect of Spark Plasma Sintering (SPS) at Temperatures of 900 and 950oc for 5 Minutes on Microstructural Formation of Fe-25Ni-17Cr Austenitic Stainless Steel

Effects of Typical Inclusions on the As‐Cast Microstructure and Recrystallization of Low‐Density Steel

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