Coarsening Kinetics of Grain Boundary in a Cast Nickel Base Superalloy during Long Term Aging

PRICM ◽  
2013 ◽  
pp. 317-325
Author(s):  
Qiang Zeng ◽  
Minghan Zhao ◽  
Ping Yan ◽  
Juntao Li ◽  
Jingchen Zhao ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Nickel Base Superalloy ◽  
Coarsening Kinetics ◽  
Nickel Base ◽  
Kinetics Of ◽  
Base Superalloy

Coarsening kinetics of γ′ precipitates in the commercial nickel base Superalloy René 88 DT

2009 ◽  
Vol 57 (8) ◽  
pp. 2538-2549 ◽  
Author(s):  
J. Tiley ◽  
G.B. Viswanathan ◽  
R. Srinivasan ◽  
R. Banerjee ◽  
D.M. Dimiduk ◽  
...  
Keyword(s):  
Nickel Base Superalloy ◽  
Coarsening Kinetics ◽  
Nickel Base ◽  
Kinetics Of ◽  
Base Superalloy

Dependence of Intergranular Fracture on Boundary Topography and Cohesion

1973 ◽  
Vol 31 ◽  
pp. 150-151
Author(s):  
J. E. Doherty ◽  
A. F. Giamei ◽  
B. H. Kear ◽  
C. W. Steinke
Keyword(s):  
Grain Boundary ◽  
Room Temperature ◽  
Nickel Base Superalloy ◽  
Boundary Shear ◽  
Room Temperature Ductility ◽  
Solid Solution Matrix ◽  
Nickel Base ◽  
Solution Matrix ◽  
Different Levels ◽  
Base Superalloy

Recently we have been investigating a class of nickel-base superalloys which possess substantial room temperature ductility. This improvement in ductility is directly related to improvements in grain boundary strength due to increased boundary cohesion through control of detrimental impurities and improved boundary shear strength by controlled grain boundary micros true tures.For these investigations an experimental nickel-base superalloy was doped with different levels of sulphur impurity. The micros tructure after a heat treatment of 1360°C for 2 hr, 1200°C for 16 hr consists of coherent precipitates of γ’ Ni3(Al,X) in a nickel solid solution matrix.

Effect of Pre-Weld Heat Treatment Temperatures on TIG Welded Microstructures on Nickel Base Superalloy, GTD-111

2015 ◽  
Vol 658 ◽  
pp. 14-18
Author(s):  
Tanaporn Rojhirunsakool ◽  
Duangkwan Thongpian ◽  
Nutthita Chuankrerkkul ◽  
Panyawat Wangyao
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Heat Treatment Temperature ◽  
Treatment Temperature ◽  
Tig Welding ◽  
Nickel Base Superalloy ◽  
Nickel Base ◽  
Base Superalloy ◽  
Weld Heat

Nickel-base superalloys have been used as high temperature materials in land-base gas turbine application. When subjected to long term, high temperature service, large crack propagation was observed. Typical refurbishment method of these turbines is carried out by using TIG welding followed by post-weld standard heat treatment. However, new crack initiation is found in the heat-affected zone after TIG welding. Pre-weld heat treatment has been discovered to improves final γ + γ’ microstructure. This study focuses on the effect of pre-weld heat treatment temperature on final γ + γ’ microstructure. Seven different conditions of pre-weld heat treatment temperature were investigated. Scanning electron microscopy studies were carried out after pre-weld and post-weld heat treatments to compare the γ + γ’ microstructure and capture microcracks. The best pre-weld heat treatment temperature produces uniform distribution of finely dispersed γ’ precipitates in the γ matrix without post-weld crack.

Influence of Etchants on Phase Morphology of Casting Ni-Based Superalloy

2014 ◽  
Vol 887-888 ◽  
pp. 366-369
Author(s):  
Juan Juan Li ◽  
Shu Jun Zang ◽  
Jian Bin Zhang
Keyword(s):  
Grain Boundary ◽  
Phase Morphology ◽  
Nickel Base Superalloy ◽  
Mixed Solution ◽  
Dendrite Structure ◽  
Etching Solution ◽  
Metallic Compounds ◽  
Nickel Base ◽  
Base Superalloy

K4169 is the Nickel-base superalloy that is the most widely used in the turbine components. The article selects three kinds of etching solution to corrode, in order to achieve the purpose that studies on its morphology. Etchant1 is the mixed solution of 15mlHCl, 10mlAcetic acid, 5mlHNO3and 2drop glycerin. Etchant2 is the mixed solution of 3ml glycerin, 3mlHCl, 1ml HNO3. Etchant 3 is the mixed solution of 20mlHNO3, 60mlHCl. The results showed that we can mainly observe strengthened phase γ'' (Ni3(Ti, Al)) and matrix γ (Fe-Ni-Cr) phase with etchant1 to corrode. Using the etchant2 to corrode, we can clearly see its dendrite structure. Using the etchant3 to corrode, we can obverse its grain boundary that includes white inter-metallic compounds. We also respectively discussed the K4169 morphology when magnifications are 200times and 500times.

The Kinetics of Precipitate Dissolution in a Nickel-Base Superalloy

2017 ◽  
Vol 48 (11) ◽  
pp. 5567-5578 ◽  
Author(s):  
S. L. Semiatin ◽  
N. C. Levkulich ◽  
A. E. Saurber ◽  
D. W. Mahaffey ◽  
E. J. Payton ◽  
...  
Keyword(s):  
Nickel Base Superalloy ◽  
Precipitate Dissolution ◽  
Nickel Base ◽  
Kinetics Of ◽  
Base Superalloy

Effect of Precipitation Aging Temperatures on Reheat Treated Microstructures and its Phase Stability after Long-Term Exposure in Cast Nickel Base Superalloy, Grade Inconel 738

2017 ◽  
Vol 891 ◽  
pp. 433-437 ◽  
Author(s):  
Nattapol Kontikame ◽  
Sureerat Polsilapa ◽  
Panyawat Wangyao
Keyword(s):  
Phase Stability ◽  
Power Plants ◽  
Turbine Blades ◽  
Research Work ◽  
Nickel Base Superalloy ◽  
Gamma Prime ◽  
Treatment Conditions ◽  
Nickel Base ◽  
Base Superalloy

This research work has an aim to investigate the effect of precipitation aging temperatures of 845°C, 865°C, 885°C and 905°C for 24 hours after solutioning treatment at temperature of 1145°C for 4 hours on final microstructure of cast nickel base superalloy, grade Inconel 738, which is used as a material for turbine blades in land base gas turbine engines to generate electricity in power plants. Further interesting is also extended to study and evaluate the phase stability of precipitated gamma prime particles after long-term heating at tempeatures of 900°C and 1000°C for 200 hours of all received final microstructures after various reheat treatment conditions. From all obtained results, it was found that the higher precipitation aging temperatures provided the more coarsening size of both coarse and fine gamma prime particles. Furthermore, after long-term exposure at high temperatures, this resulted in an increasing of both area density and size of gamma prime particles.

Long-Term Gamma Prime Phase Stability after Various Heat Treatment Conditions with Temperature Dropping during Solution Treatment in Cast Nickel Base Superalloy, Grade Inconel-738

2017 ◽  
Vol 891 ◽  
pp. 420-425
Author(s):  
Sureerat Polsilapa ◽  
Aimamorn Promboopha ◽  
Panyawat Wangyao
Keyword(s):  
Heat Treatment ◽  
Turbine Blades ◽  
Solution Treatment ◽  
Nickel Base Superalloy ◽  
Gamma Prime ◽  
Nickel Based Superalloy ◽  
Treatment Conditions ◽  
Nickel Base ◽  
Base Superalloy

Cast nickel based superalloy, Grade Inconel 738, is a material for turbine blades. Its rejuvenation heat treatment usually consist of solution treatment condition with temperature range of 1125-1205 oC for 2-6 hours. Then it is following with double aging process including primary aging at 1055oC for 1 hour and secondary aging at 845oC for 24 hours. However, the various selected temperature dropping program were performed during solution treatment to simulate the possible error of heating furnace. The maximum number of temperature dropping during solution treatment is varied from 1-3 times From all obtained results, the various temperature dropping during solution treatment conditions showed extremely the significant effect on the final rejuvenated microstructures and long-term gamma prime stability after heating at temperature of 900oC for 200 hours.

Effect of Long-Term Aging on Microstructural Restoration in Cast Nickel Base Superalloy, GTD-111

2017 ◽  
Vol 891 ◽  
pp. 426-432 ◽  
Author(s):  
Chuleeporn Paa-Rai ◽  
J. Norachan ◽  
Panyawat Wangyao ◽  
Sureerat Polsilapa ◽  
Gobboon Lothongkum
Keyword(s):  
Aging Time ◽  
Research Study ◽  
Volume Fraction ◽  
Area Fraction ◽  
Nickel Base Superalloy ◽  
Final Microstructure ◽  
Reheat Treatment ◽  
Nickel Base ◽  
Base Superalloy

In this research study, the effect of long-term aging after various solutioning temperatures on final microstructure was investigated. The cast nickel base superalloy, GTD-111, usually has standard reheat treatment as follows: solutioning treatment at 1448 - 1478 K for 7.2 ‑ 21.6 ks and aging at 1118 K for 86.4 ks. However, from previous research works, the density of γ՛ phase was not reached the optimum value. Therefore, extension of aging time was performed in the study from 90 to 180, 270, 360, 720, 1080 and 1440 ks in order to increase density or volume fraction of precipitating γ՛ particles. From the results, it was found that longer aging time provided higher values of both area fraction and size of γ՛ particles. However, increase in aging time resulted in the hardness decrease.

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