Abnormal Increase of TCP Phase During Heat Treatment in a Ni-Based Single Crystal Superalloy

Taking nickel-based single crystal superalloy DD6 as the research object, different degrees of creep damage were prefabricated by creep interruption tests, and then the creep damage was repaired by the restoration heat treatment system of solid solution heat treatment and two-stage aging heat treatment. The results show that with the creep time increasing, the alloy underwent microstructure evolution including γ′ phase coarsening, N-type rafting and de-rafting. After the restoration heat treatment, the coarse rafted γ′ phase of creep damaged specimens dissolved, precipitated, grew up, and became cubic again. Except for the specimens with creep interruption of 100 h, the γ′ phase can basically achieve the same arrangement as the γ′ phase of the original sample. The comparison of the secondary creep test shows that the steady-state creep stage of the test piece after the restoration heat treatment is relatively increased, and the total creep life can reach the same level as the primary creep life. The high temperature creep properties of the tested alloy are basically recovered, and the restoration heat treatment effect is good.

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Creep Behavior of a 4.5% Re Nickel-Base Single Crystal Superalloy at High Temperature

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.750.139 ◽

2015 ◽

Vol 750 ◽

pp. 139-144 ◽

Cited By ~ 1

Author(s):

De Long Shu ◽

Su Gui Tian ◽

Xin Ding ◽

Jing Wu ◽

Qiu Yang Li ◽

...

Keyword(s):

Heat Treatment ◽

High Temperature ◽

Single Crystal ◽

Deformation Mechanism ◽

Creep Property ◽

Single Crystal Superalloy ◽

Micro Cracks ◽

Initiation And Propagation ◽

Temperature Ranges ◽

Nickel Base

By means of heat treatment and creep property measurement, an investigation has made into the creep behaviors of a containing 4.5% Re nickel-base single crystal superalloy at high temperature. Results show that the elements W, Mo and Re are enriched in the dendrite arm regions, the elements Al, Ta, Cr and Co are enriched in the inter-dendrite region, and the segregation extent of the elements may be obviously reduced by means of heat treatment at high temperature. In the temperature ranges of 1070--1100 °C, the 4.5% Re single crystal nickel-based superallloy displays a better creep resistance and longer creep life. The deformation mechanism of the alloy during steady state creep is dislocations slipping in the γ matrix and climbing over the rafted γ′ phase. In the later stage of creep, the deformation mechanism of alloy is dislocations slipping in the γ matrix, and shearing into the rafted γ′ phase, which may promote the initiation and propagation of the micro-cracks at the interfaces of γ/γ′ phases up to the occurrence of creep fracture.

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Research Progress in Nickel Base Single Crystal Superalloys

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.861.113 ◽

2020 ◽

Vol 861 ◽

pp. 113-121

Author(s):

Zhao Jun Jiang ◽

Jun Wang ◽

Dong Mei Cao

Keyword(s):

Heat Treatment ◽

Single Crystal ◽

New Technologies ◽

Single Crystal Superalloy ◽

Research Progress ◽

Market Demand ◽

Theoretical Simulation ◽

Characterization Methods ◽

Composition Design ◽

Nickel Base

Nickel base single crystal superalloy is widely used in hot end parts of aeroengine because of its excellent creep, fatigue and oxidation resistance. In the face of strong market demand and the emergence of new technologies and methods, in 2019, nickel-based single crystal superalloys have made remarkable achievements in preparation and heat treatment processes, repair techniques, test methods, characterization methods, theoretical simulation analysis and composition design, which continuously promotes the development of nickel base single crystal superalloy to the direction of high performance and low cost. The present work reviews the progresses from preparation and heat treatment process, repair technology of service alloy structure, service evaluation of alloy, high flux composition design. The progress in the design, preparation and engineering application of superalloy materials will eventually promote the development of a new generation of aeroengine.

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Effect of grit blasting and subsequent heat treatment on stress rupture property of a Ni-based single-crystal superalloy SGX3

Acta Metallurgica Sinica (English Letters) ◽

10.1007/s40195-020-01051-x ◽

2020 ◽

Vol 33 (12) ◽

pp. 1681-1688

Author(s):

Jinshan He ◽

Zhengrong Yu ◽

Longfei Li ◽

Xitao Wang ◽

Qiang Feng

Keyword(s):

Heat Treatment ◽

Single Crystal ◽

Stress Rupture ◽

Subsequent Heat Treatment ◽

Single Crystal Superalloy ◽

Stress Rupture Property ◽

Grit Blasting

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The Microstructure Evolution of a Nickel-Base Single Crystal Superalloy after Long-Term Aging

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1088.217 ◽

2015 ◽

Vol 1088 ◽

pp. 217-220 ◽

Cited By ~ 1

Author(s):

Yu Xian Jia

Keyword(s):

Single Crystal ◽

Exposure Time ◽

Microstructure Evolution ◽

Ageing Time ◽

Thermal Exposure ◽

Single Crystal Superalloy ◽

Phase Precipitation ◽

Tcp Phase ◽

Nickel Base

Microstructure evolution of a nickel-base single crystal superalloy during thermal exposure at 982°C was investigated. The SEM studies revealed that the size of γ' phase increased and some of which linked together with the elongation of the exposure time. There is acicular phase precipitation after the long-term ageing treatment. The TCP phase is not increased by the increment of ageing time after reaching a certain amount. There are skeleton shape carbides precipitate after 100h and 300h. The amount of precipitated carbides decreases by the elongation of ageing time.

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