Quantitative Metallography of the Age Hardening Precipitate in Superalloys by Replica Electron Microscopy

Seher, RJ; James, HM; Maniar, GN

doi:10.1520/stp36847s

Cited by 12 publications

(10 citation statements)

References 2 publications

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“…In each replica, a population of no less 200 particles was counted, and their size was measured with the aim of calculating the mean size, particle density and volume fraction. The volume fraction was calculated by the Maniar's method [19]. Thin foils samples were also prepared by electrolytic polishing using a solution of acetic acid (95%) and perchloric acid (5%), at room temperature (~ 25 o C).…”

Section: Methodsmentioning

confidence: 99%

Interaction between recrystallization and strain-induced precipitation in a high Nb- and N-bearing austenitic stainless steel: Influence of the interpass time

Silva

Gallego

Cabrera

et al. 2015

Materials Science and Engineering: A

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In this work, we studied the influence of the interpass time (20 and 5 s) on the interaction between recrystallization and strain-induced precipitation occurring during multiple passes' deformations under continuous cooling conditions in a high niobium-and nitrogen-bearing austenitic stainless steel (ISO 5832-9). The correlation between microstructure evolution and hot mechanical properties was performed by physical simulation using hot torsion tests. The microstructure evolution was analyzed by optical microscopy, transmission electron microscopy and electron back scattered diffraction (EBSD). This technique indicated that dynamic recrystallization occurred at the first passes promoting an excellent grain refinement. On the other hand, shorter interpass time (5 s) allowed higher volume fraction of smallest precipitates than larger interpass time (20 s). After soaking, only TiNbN precipitates were found, whereas, Z-phase (CrNbN) and NbN were formed during thermomechanical processing. Particles with sizes between 20 and 50 nm were effective to pin grain boundaries and dislocations.2

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Section: Methodsmentioning

confidence: 99%

Interaction between recrystallization and strain-induced precipitation in a high Nb- and N-bearing austenitic stainless steel: Influence of the interpass time

Silva

Gallego

Cabrera

et al. 2015

Materials Science and Engineering: A

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“…The size and volume fraction of the c¢ precipitates were determined by the Fullman Intercept Method at the same horizontal cross sections which were used for DAS calculations. [23] Microprobe investigations with a JEOL JXA-8100 system were performed to examine element segregations within the samples. DSC analysis with a heating rate of 5 K/min was performed with a Netzsch STA409.…”

Section: B Sample Preparationmentioning

confidence: 99%

Microstructure of the Nickel-Base Superalloy CMSX-4 Fabricated by Selective Electron Beam Melting

Ramsperger

Singer

Körner

2016

Metall Mater Trans A

194

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Powder bed-based additive manufacturing (AM) processes are characterized by very hightemperature gradients and solidification rates. These conditions lead to microstructures orders of magnitude smaller than in conventional casting processes. Especially in the field of high performance alloys, like nickel-base superalloys, this opens new opportunities for homogenization and alloy development. Nevertheless, the high susceptibility to cracking of precipitation-hardenable superalloys is a challenge for AM. In this study, electron beam-based AM is used to fabricate samples from gas-atomized pre-alloyed CMSX-4 powder. The influence of the processing strategy on crack formation is investigated. The samples are characterized by optical and SEM microscopy and analyzed by microprobe analysis. Differential scanning calorimetry is used to demonstrate the effect of the fine microstructure on characteristic temperatures. In addition, in situ heat treatment effects are investigated.

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“…In order to calculate the contribution of the precipitates to yield strength, we employed segment calculation and summation of the results (Table 5). According to the methods of McCall-Boyd [26] and the Ashby-Orowan correction model [27], the formula for the volume fraction and precipitation strengthening of the precipitates in H13 is obtained as Formulas (12) and (13). McCall and Boyd [28] analyzed the characteristics of precipitates in ThO 2 by employing carbon extraction replica methods in the 1960s.…”

Section: Effect Of Precipitates In H13 During Tempering On Mechanicalmentioning

confidence: 99%

Precipitation Behavior of Carbides in H13 Hot Work Die Steel and Its Strengthening during Tempering

Ning

Mao

Chen

et al. 2017

Metals

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Abstract:The properties of carbides, such as morphology, size, and type, in H13 hot work die steel were studied with optical microscopy, transmission electron microscopy, electron diffraction, and energy dispersive X-ray analysis; their size distribution and quantity after tempering, at different positions within the ingot, were analyzed using Image-Pro Plus software. Thermodynamic calculations were also performed for these carbides. The microstructures near the ingot surface were homogeneous and had slender martensite laths. Two kinds of carbide precipitates have been detected in H13: (1) MC and M 6 C, generally smaller than 200 nm; and (2) M 23 C 6 , usually larger than 200 nm. MC and M 6 C play the key role in precipitation hardening. These are the most frequent carbides precipitating at the halfway point from the center of the ingot, and the least frequent at the surface. From the center of the ingot to its surface, the size and volume fraction of the carbides decrease, and the toughness improves, while the contribution of the carbides to the yield strength increases.

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Quantitative Metallography of the Age Hardening Precipitate in Superalloys by Replica Electron Microscopy

Cited by 12 publications

References 2 publications

Interaction between recrystallization and strain-induced precipitation in a high Nb- and N-bearing austenitic stainless steel: Influence of the interpass time

Interaction between recrystallization and strain-induced precipitation in a high Nb- and N-bearing austenitic stainless steel: Influence of the interpass time

Microstructure of the Nickel-Base Superalloy CMSX-4 Fabricated by Selective Electron Beam Melting

Precipitation Behavior of Carbides in H13 Hot Work Die Steel and Its Strengthening during Tempering

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