Influence of precipitate morphology on tensile creep of a single crystal nickel-base superalloy

2007 ◽  
Vol 454-455 ◽  
pp. 461-466 ◽  
Author(s):  
Li Shui ◽  
Tao Jin ◽  
Sugui Tian ◽  
Zhuangqi Hu
Keyword(s):  
Single Crystal ◽  
Tensile Creep ◽  
Nickel Base Superalloy ◽  
Precipitate Morphology ◽  
Nickel Base ◽  
Base Superalloy

Microstructure Evolution and Strain Features of a Single Crystal Nickel Base Superalloy during Tensile/Compression Creep

2007 ◽  
Vol 546-549 ◽  
pp. 1225-1228
Author(s):  
Fan Lai Meng ◽  
Su Gui Tian ◽  
Ming Gang Wang ◽  
Xing Fu Yu ◽  
Hong Qiang Du ◽  
...  
Keyword(s):  
Single Crystal ◽  
Microstructure Evolution ◽  
Tensile Creep ◽  
Stress Axis ◽  
Nickel Base Superalloy ◽  
Direction Parallel ◽  
Compression Creep ◽  
Nickel Base ◽  
P Type ◽  
Base Superalloy

By means of tensile and compression creep testing and SEM, TEM observation, an investigation has been made into the microstructure evolution of a single crystal nickel base superalloy during tensile / compression creep. Results show that the cubic γ′ phase in the superalloy is transformed into the N-type meshlike structure along the direction vertical to stress axis during tensile creep. The cubic γ′ phase is transformed into the P-type structure along the direction parallel to stress axis during compression creep. An obvious asymmetry strain of the alloy occurs during tensile and compression creep, the formation of the needle-like γ′ rafts during compression creep is a main reason of the alloy displaying a smaller strain. During compressive creep, the deformation feature of the alloy is the <110> and (1/3) <112> super dislocations shearing into the γ′ rafts. The deformation mechanism of the alloy, in the stage state of tensile creep, is dislocation climb over the γ′ rafts.

Microstructural Evolution during Tensile Creep of a Single-Crystal Nickel-Base Superalloy

2007 ◽  
Vol 353-358 ◽  
pp. 511-514
Author(s):  
Ying Li ◽  
Hui Chen Yu ◽  
Xue Ren Wu ◽  
Xiao Guang Yang ◽  
Duo Qi Shi
Keyword(s):  
Electron Microscope ◽  
Single Crystal ◽  
Microstructural Evolution ◽  
Tensile Creep ◽  
Creep Process ◽  
Nickel Base Superalloy ◽  
Creep Tests ◽  
Transmission Electron ◽  
Nickel Base ◽  
Base Superalloy

Tensile creep tests were conducted at 980°C under a constant stress on a single crystal nickel base superalloy. Some tests were interrupted at different stages during the creep process. The strain-time curves indicated that this alloy exhibited conventional primary, steady-state and tertiary stages at this temperature. The transmission electron microscope (TEM) observations of foils taken from the gauge sections of specimens were made to interpret the microstructural evolution that occurred during the creep process. It was found that the γ′ particles were rafted in the direction perpendicular to the applied stress. The acceleration of the creep rate was related to the change of the dislocation density.

Microstructure evolution of a [011] orientation single crystal nickel-base superalloy during tensile creep

2011 ◽  
Vol 104 (2) ◽  
pp. 643-647 ◽  
Author(s):  
Sugui Tian ◽  
Yong Su ◽  
Lili Yu ◽  
Huichen Yu ◽  
Shu Zhang ◽  
...  
Keyword(s):  
Single Crystal ◽  
Microstructure Evolution ◽  
Tensile Creep ◽  
Nickel Base Superalloy ◽  
Nickel Base ◽  
Base Superalloy

Characterization of Coherent, Ordered Precipitates in Nickel-Base Alloys

1973 ◽  
Vol 31 ◽  
pp. 144-145
Author(s):  
B. H. Kear ◽  
J. M. Oblak
Keyword(s):  
Stable Phase ◽  
Nickel Base Superalloy ◽  
Alloy 718 ◽  
Commercial Alloy ◽  
Precipitate Morphology ◽  
Continuous Precipitation ◽  
Nickel Base ◽  
Base Superalloy ◽  
Strengthening Precipitate

A nickel-base superalloy is essentially a Ni/Cr solid solution hardened by additions of Al (Ti, Nb, etc.) to precipitate a coherent, ordered phase. In most commercial alloy systems, e.g. B-1900, IN-100 and Mar-M200, the stable precipitate is Ni3 (Al,Ti) γ′, with an LI2structure. In A lloy 901 the normal precipitate is metastable Nis Ti3 γ′ ; the stable phase is a hexagonal Do2 4 structure. In Alloy 718 the strengthening precipitate is metastable γ″, which has a body-centered tetragonal D022 structure.Precipitate MorphologyIn most systems the ordered γ′ phase forms by a continuous precipitation re-action, which gives rise to a uniform intragranular dispersion of precipitate particles. For zero γ/γ′ misfit, the γ′ precipitates assume a spheroidal.

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