Development of New PM Superalloys for High Temperature Applications

Locq, Didier; Marty, M.; Walder, A.; Caron, Pierre

doi:10.1002/3527607285.ch9

Cited by 14 publications

(12 citation statements)

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“…NR3 alloy is a superalloy developed at ONERA for high temperature disk applications (ONERA-SNECMA patent) [7]. Its chemistry (Table I) was defined in order to avoid the precipitation of harmful intergranular and intragranular topologically closepacked (TCP) phase particles which can occur during long-term exposures at high temperatures.…”

Section: Methodsmentioning

confidence: 99%

On the Role of Tertiary γ' Precipitates in the Creep Behaviour at 700�C of a PM Disk Superalloy

Locq¹,

Caron²,

Raujol³

et al. 2004

Superalloys 2004 (Tenth International Symposium)

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The creep behaviour of the PM NR3 nickel-based superalloy has been studied at 700°C in a wide stress range as a function of its microstructure. It was first confirmed that at this critical temperature a coarse-grained microstructure was preferable to a fine-grained one to obtain the highest creep resistance. The role of the tertiary γ ′ phase precipitates in the creep behaviour of coarsegrained NR3 was investigated at two stress levels typical of both low stress and high stress creep regimes. Careful identification of dislocation mechanisms by transmission electron microscopy was performed in creep strained specimens in order to correlate the macroscopic behaviour with the creep controlling mechanisms. Prior elimination of the tertiary γ ′ precipitates using an adequate overageing heat treatment promotes easy glide of a/2<110> perfect matrix dislocations between the secondary γ ′ precipitates and therefore confers to the alloy a poor creep resistance. On the contrary the presence of fine tertiary γ ′ particles impedes propagation of the perfect matrix dislocations which are forced to cut the γ ′ precipitates through two different modes of dissociation depending on the local precipitate distribution. Reduction of the γ phase channel width promotes the decorrelation in the matrix of the two a/6<112> partial dislocations constituting an a/2<110> perfect dislocation. This mechanism which leads to stacking fault configurations extending through both γ and γ ′ phases evidences the strong resistance of the microstructure against creep deformation. Coupled analysis of the creep behaviour and of the dislocation structures in the low stress creep regime indicates a growing involvement of the grain boundary areas in the macroscopic creep deformation.

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Section: Methodsmentioning

confidence: 99%

On the Role of Tertiary γ' Precipitates in the Creep Behaviour at 700�C of a PM Disk Superalloy

Locq¹,

Caron²,

Raujol³

et al. 2004

Superalloys 2004 (Tenth International Symposium)

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“…This phase gives the superalloy a principal yield strength which increases with a temperature rise. They may have equiaxed or columnar grain structures without exhibiting high-angle grain boundaries, which at high temperatures are sites for damage accumulation [20]. According to Graybill, Li [21], Superalloy's strengthening mechanism includes dispersion strengthening, solid solution and precipitation strengthening [22].…”

Section: Super Alloysmentioning

confidence: 99%

Recent Advances of High Entropy Alloys: High Entropy Superalloys

Dada¹,

Popoola²,

Mathe³

et al. 2021

Advances in High-Entropy Alloys - Materials Research, Exotic Properties and Applications

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“…), and piping for heat exchangers [ 1 , 2 ]. Of particular relevance is their use in components high temperature applications such as disks and the blades of aeronautic engines and gas turbines [ 3 , 4 , 5 , 6 , 7 ]. Their microstructure mainly consists of particles of the L12 ordered Ni 3 (Al,Ti) γ’ phase embedded in the disordered γ phase matrix [ 8 ].…”

Section: Introductionmentioning

confidence: 99%

Electron Beam Welding of IN792 DS: Effects of Pass Speed and PWHT on Microstructure and Hardness

et al. 2017

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Electron Beam (EB) welding has been used to realize seams on 2 mm-thick plates of directionally solidified (DS) IN792 superalloy. The first part of this work evidenced the importance of pre-heating the workpiece to avoid the formation of long cracks in the seam. The comparison of different pre-heating temperatures (PHT) and pass speeds (v) allowed the identification of optimal process parameters, namely PHT = 300 • C and v = 2.5 m/min. The microstructural features of the melted zone (MZ); the heat affected zone (HAZ), and base material (BM) were investigated by optical microscopy (OM), scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS), electron back-scattered diffraction (EBSD), X-ray diffraction (XRD), and micro-hardness tests. In the as-welded condition; the structure of directionally oriented grains was completely lost in MZ. The γ' phase in MZ consisted of small (20-40 nm) round shaped particles and its total amount depended on both PHT and welding pass speed, whereas in HAZ, it was the same BM. Even if the amount of γ' phase in MZ was lower than that of the as-received material, the nanometric size of the particles induced an increase in hardness. EDS examinations did not show relevant composition changes in the γ' and γ phases. Post-welding heat treatments (PWHT) at 700 and 750 • C for two hours were performed on the best samples. After PWHTs, the amount of the ordered phase increased, and the effect was more pronounced at 750 • C, while the size of γ' particles in MZ remained almost the same. The hardness profiles measured across the joints showed an upward shift, but peak-valley height was a little lower, indicating more homogeneous features in the different zones.

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Development of New PM Superalloys for High Temperature Applications

Cited by 14 publications

References 0 publications

On the Role of Tertiary γ' Precipitates in the Creep Behaviour at 700�C of a PM Disk Superalloy

On the Role of Tertiary γ' Precipitates in the Creep Behaviour at 700�C of a PM Disk Superalloy

Recent Advances of High Entropy Alloys: High Entropy Superalloys

Electron Beam Welding of IN792 DS: Effects of Pass Speed and PWHT on Microstructure and Hardness

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Development of New PM Superalloys for High Temperature Applications

Cited by 14 publications

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On the Role of Tertiary &#947;' Precipitates in the Creep Behaviour at 700�C of a PM Disk Superalloy

On the Role of Tertiary &#947;' Precipitates in the Creep Behaviour at 700�C of a PM Disk Superalloy

Recent Advances of High Entropy Alloys: High Entropy Superalloys

Electron Beam Welding of IN792 DS: Effects of Pass Speed and PWHT on Microstructure and Hardness

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Product

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On the Role of Tertiary γ' Precipitates in the Creep Behaviour at 700�C of a PM Disk Superalloy

On the Role of Tertiary γ' Precipitates in the Creep Behaviour at 700�C of a PM Disk Superalloy