STEM microanalysis of precipitates and their nuclei in a nickel-base superalloy

Menzies, R. G.; Bricknell, R.H.; Craven, A. J.

doi:10.1080/01418618008239328

Cited by 40 publications

(5 citation statements)

References 6 publications

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“…As mentioned previously, the precipitates on PPB can be divided into two types, namely, the small refractory oxide and blocky carbide compounds, and the irregularly large γ′. The oxide and carbide are mainly formed by diffusion and segregation of Zr, Ti, Nb, etc., for example, the Zr could react with residual oxygen in the container at extremely low partial oxygen pressure and moderate temperature; some of the oxides may have already formed during atomization prior to consolidation [ 20 , 26 , 27 ]. The stable MC-type carbide starts to precipitate by element segregation or dissolution of metastable carbide which releases the forming elements of the carbide [ 24 , 28 ].…”

Section: Discussionmentioning

confidence: 99%

Effects of Temperature and Pressure of Hot Isostatic Pressing on the Grain Structure of Powder Metallurgy Superalloy

Tan

Liu

et al. 2018

Materials

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The microstructure with homogeneously distributed grains and less prior particle boundary (PPB) precipitates is always desired for powder metallurgy superalloys after hot isostatic pressing (HIPping). In this work, we studied the effects of HIPping parameters, temperature and pressure on the grain structure in PM superalloy FGH96, by means of scanning electron microscope (SEM), electron backscatter diffraction (EBSD), transmission electron microscope (TEM) and Time-of-flight secondary ion spectrometry (ToF-SIMS). It was found that temperature and pressure played different roles in controlling PPB precipitation and grain structure during HIPping, the tendency of grain coarsening under high temperature could be inhibited by increasing HIPping pressure which facilitates the recrystallization. In general, relatively high temperature and pressure of HIPping were preferred to obtain an as-HIPped superalloy FGH96 with diminished PPB precipitation and homogeneously refined grains.

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Section: Discussionmentioning

confidence: 99%

Effects of Temperature and Pressure of Hot Isostatic Pressing on the Grain Structure of Powder Metallurgy Superalloy

Tan

Liu

et al. 2018

Materials

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“…Figure 7c,d provides an examples of monoclinic m-ZrO 2 occasionally found in polycrystalline Ni-based superalloys. [31,111,[162][163][164][165][166] A number of studies on PM processed Ni-based superalloys report on ZrO 2 . [164][165][166] Here, its role as nucleation site for MC carbides may depend on individual superalloy composition and thermomechanical processing.…”

Section: Precipitation Of Zr-rich Phasesmentioning

confidence: 99%

Review of Microstructure–Mechanical Property Relationships in Cast and Wrought Ni‐Based Superalloys with Boron, Carbon, and Zirconium Microalloying Additions

et al. 2022

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Cast and wrought Ni‐based superalloys are materials of choice for harsh high‐temperature environments of aircraft engines and gas turbines. Their compositional complexity requires sophisticated thermo‐mechanical processing. A typical microstructure consists of a polycrystalline γ‐matrix, strengthening Ni3(Al,Ti) γ′ precipitates, carbides (MC, M6C, and M23C6), borides (M2B, M3B2, and M5B3), and other inclusions. Microalloying additions of B, C, and Zr commonly improve high‐temperature strength and creep resistance, although excessive additions are detrimental. Grain boundary (GB) segregation may improve cohesion and displace embrittling impurities. Finely dispersed carbides and borides are desired to control grain size via GB pinning. However, excessive decoration of GBs may lead to failure during processing and in‐service. Hence, a systematic review on the roles of B, C, and Zr in cast and wrought Ni‐based superalloys is required. The current state of knowledge on GB segregation and precipitation is reviewed. Experimental and modeling results are compared across various processing steps. The impact of GB precipitation on mechanical properties is most well researched. Co‐precipitation in proximity to GBs interacting with local microstructure evolution and mechanical properties remains less explored. Addressing these gaps in knowledge allows a more complete understanding of processing–microstructure–properties relationships in advanced cast and wrought Ni‐based superalloys.

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“…In the case of as-HIPped Ti-based alloys, PPBs and porosity are generally not present whereas inclusions are observed occasionally which could act as crack initiators and cause scatter in ductility [5]. As far as as-HIPped nickel-based superalloys are concerned, PPBs due to carbide or oxide decoration are a very common issue and thermally-induced pores could be formed if high temperature post-HIP heat treatments are conducted [6][7][8][9][10][11][12][13][14]. PPBs are vulnerable sites for crack initiation and propagation and thus very harmful for high temperature mechanical properties of Ni-based superalloys, especially for hot ductility, low cycle fatigue (LCF) properties and stress rupture properties [15][16].…”

Section: Introductionmentioning

confidence: 99%

High cycle fatigue and fracture behaviour of a hot isostatically pressed nickel-based superalloy

Qiu

2013

Philosophical Magazine

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show abstract

STEM microanalysis of precipitates and their nuclei in a nickel-base superalloy

Cited by 40 publications

References 6 publications

Effects of Temperature and Pressure of Hot Isostatic Pressing on the Grain Structure of Powder Metallurgy Superalloy

Effects of Temperature and Pressure of Hot Isostatic Pressing on the Grain Structure of Powder Metallurgy Superalloy

Review of Microstructure–Mechanical Property Relationships in Cast and Wrought Ni‐Based Superalloys with Boron, Carbon, and Zirconium Microalloying Additions

High cycle fatigue and fracture behaviour of a hot isostatically pressed nickel-based superalloy

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