Creep-rupture behavior of a nickel-based single crystal superalloy

This work assesses the effects of the surface recrystallization of the processing of water grit blasting, grit blasting and mechanically polishing on the microstructures and creep rupture properties of DD6 alloy, a low-cost second generation single crystal superalloy. The results demonstrate that the possibility and the depth of the surface recrystallization of DD6 show an increase as the annealing temperature increases from 1050°C to 1250°C. No surface recrystallization happens when the specimens of the alloy have been undergone at 1100°C for 4 hours after water grit blasting, but the surface recrystallization occurs at the annealing temperature above 1200°C for 4 hours after water grit blasting. The test indicates that the increasing pre-deformation decreases the surface recrystallization temperature. The creep rupture life of DD6 alloy without processing is 274.4 hours, 341.1 hours at the conditions of 980°C/250MPa, 1070°C/140MPa respectively. After annealing at 1100°C for 4 hours, the creep rupture life of the alloy with the processing of water grit blasting is equivalent to that of the alloy without processing. The surface recrystallization of the alloy happens with the processing of grit blasting after the annealing at 1100°C for 4 hours, and there is a reduction of the creep rupture life at the conditions as mentioned above. The creep properties of DD6 alloy meet the needs of blades and vanes of single crystal for advanced aeroengines when the surface recrystallization of the alloy occurs during manufacturing and processing.

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Effect of Squareness of Initial γ′ Precipitates on Creep-Rupture Life of a Ni-Base Single Crystal Superalloy at 760/982 °C

Metallurgical and Materials Transactions A ◽

10.1007/s11661-018-4635-y ◽

2018 ◽

Vol 49 (7) ◽

pp. 2929-2939

Author(s):

Zhenbin Shi ◽

Zhifang Peng ◽

Yushi Luo ◽

Hongji Xie ◽

Haipeng Jin ◽

...

Keyword(s):

Single Crystal ◽

Rupture Life ◽

Creep Rupture ◽

Single Crystal Superalloy

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New configuration of a [001] superdislocation formed during high-temperature creep in the γ′ phase of a single-crystal superalloy TMS-138

Journal of Materials Research ◽

10.1557/jmr.2006.0085 ◽

2006 ◽

Vol 21 (3) ◽

pp. 647-654 ◽

Cited By ~ 13

Author(s):

J.X. Zhang ◽

H. Harada ◽

Y. Koizumi

Keyword(s):

High Temperature ◽

Tensile Test ◽

Single Crystal ◽

Creep Rupture ◽

Single Crystal Superalloy ◽

Fourth Generation ◽

High Temperature Creep ◽

Burgers Vector ◽

Temperature Creep ◽

Interfacial Dislocations

A new configuration of a superdislocation in the γ′ phase of a fourth-generation single-crystal TMS-138 superalloy was found after creep rupture in a [001] tensile test at 1150 °C and 137 MPa. The segments of the superdislocation lie in four directions, i.e., [110], [110], [100], and [010], strictly on a (001) plane with a Burgers vectorb= [001]. This superdislocation is pure edge in character and does not dissociate into superpartials. Microstructural evidence shows that this kind of superdislocation is formed by combination of two interfacial dislocations with different Burgers vectors, i.e., 1/2[011] + 1/2[011] → [001].

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