In-Service Mechanical Property Degradation of Cocraiy Coatings in Land-Based Gas Turbine Blades

1998 ◽  
Author(s):  
J. Kameda ◽  
T.E. Bloomer ◽  
S. Sakurai
Keyword(s):  
Gas Turbine ◽  
Degradation Mechanism ◽  
Turbine Blades ◽  
Significant Loss ◽  
Nickel Titanium ◽  
Near Surface ◽  
Gas Turbine Blades ◽  
Surface And Interface ◽  
Service Degradation ◽  
Plasma Sprayed

Abstract This paper describes variations in the microstructure/composition and mechanical properties in plasma sprayed CoCrAlY coatings and a modified Rene 80 substrate of gas turbine blades operated for 21000 h under liquefied natural gas fuels. Substantial oxidation/carbonization occurred in near surface coatings of concave blades but not in convex coatings. Aluminum and nickel/titanium rich nitrides formed in concave coatings and substrates adjacent to the interface, respectively. Small punch (SP) specimens were prepared in order that the specimen surface would be located in the near surface and interface regions of the concave and convex coatings. In SP tests, brittle cracks in the near surface and interface coatings of the concave blade initiated at low strains up to 950 °C. The convex coatings had higher ductility than the concave coatings and substrate and showed a rapid increase in the ductility above 800 °C. Thus it is apparent that the oxidation/carbonization and nitridation in the concave coatings produced a significant loss of the ductility. The in-service degradation mechanism of the CoCrAlY coatings is discussed in light of the operating temperature distribution and compared to that of CoNiCrAIY coatings induced by grain boundary sulfidation/oxidation.

A204 In-Service Degradation of Refurbished Gas Turbine Blades

2008 ◽  
Vol 2008.13 (0) ◽  
pp. 289-290
Author(s):  
Akihiro ITO ◽  
Yukio KAGIYA ◽  
Hideyuki ISHIGAMI ◽  
Tomoaki ANDO ◽  
Daizo SAITO ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Turbine Blades ◽  
Gas Turbine Blades ◽  
Service Degradation

Ductility Loss in Aluminized CoCrAlY Coatings Exposed to In-Service Environment

2001 ◽  
Author(s):  
N. Shinohara ◽  
A. Ito ◽  
K. Sugiyama ◽  
Y. Sugita ◽  
J. Kameda ◽  
...  
Keyword(s):  
Gas Turbines ◽  
Degradation Mechanism ◽  
Turbine Blades ◽  
Leading Edge ◽  
Testing Temperature ◽  
Thermal Ageing ◽  
Near Surface ◽  
Ductility Loss ◽  
Service Operation ◽  
Service Degradation

By applying a small punch testing technique, it has been previously shown that near-surface aluminized CoCrAlY coatings of unused advanced gas turbine blades had very low ductility due to the formation of Al and Cr rich phases, compared to internal and near-interface regions. Thus, it is important to examine how in-service operation affects the mechanical properties of the internal, near-interface coatings and substrates to maintain the integrity of gas turbines. This study attempts to compare the effects of in-service operation for 20,000 h under combustion of liquefied natural gas and thermal ageing in air. The in-service operation led to a larger ductility loss in concave coatings near the tailing edge, although the ductility slightly improved above testing temperature at 950 °C. Substrate used in-service had lower ductility at 950 °C than the used concave coatings. The ductility of used internal coatings depended on the blade location. In convex coatings near the leading edge, in-service degradation was not significant and the ductility was about two-fold greater than in the thermally aged blade. The in-service degradation mechanism of the aluminized CoCrAlY coatings is discussed in light of the operating temperature distribution and microstructural evolution.

scholarly journals In-Service Degradation of Metallurgical and Mechanical Properties of Aluminized Coatings and Substrates in Gas Turbine Blades

2002 ◽  
Vol 43 (1) ◽  
pp. 11-18 ◽  
Author(s):  
Akihiro Ito ◽  
Kazuhiro Sugiyama ◽  
Nobuo Shinohara ◽  
Yuji Sugita ◽  
Shigeo Sakurai ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Gas Turbine ◽  
Turbine Blades ◽  
Gas Turbine Blades ◽  
Service Degradation

Thermal Analysis & Studies on Low Pressure Gas Turbine Blades Coated with Yitria Stabilized Zirconia (YSZ)

2012 ◽  
Vol 622-623 ◽  
pp. 1596-1600
Author(s):  
N. Rajasekar ◽  
P.M. Shivraj ◽  
C.J. Thomas Renald ◽  
K. Karthick ◽  
M.P. Tamizhmani
Keyword(s):  
Gas Turbine ◽  
Turbine Blades ◽  
Thermal Barrier ◽  
Stabilized Zirconia ◽  
Turbine Engine ◽  
Gas Turbine Blades ◽  
Barrier Coating ◽  
Potential Applications ◽  
Plasma Sprayed ◽  
Engine Components

The thermal barrier coatings have many potential applications in the protection of gas turbine engine components, essentially the turbine blades.In this study micro analysis was carried out on Yitria Stabilized Zirconia(YSZ) coated turbine blades and the results are compared with the uncoated blades.We have used the atmosphere plasma sprayed thermal barrier coating with a thickness of 0.25mm to withstand the high temperature of about 2000 C.We observed that by increasing the thermal coating thickness of about 0.25mm cause to increase 50% of the surface temperature of the turbine blade,which in turn increased the aero engine thrust.

UDIMET L-605

Alloy Digest ◽  
2004 ◽  
Vol 53 (12) ◽  
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Gas Turbine ◽  
Oxidation Resistance ◽  
Turbine Blades ◽  
Heat Treating ◽  
Gas Turbine Blades ◽  
Temperature Performance

Abstract Udimet L-605 is a high-temperature aerospace alloy with excellent strength and oxidation resistance. It is used in applications such as gas turbine blades and combustion area parts. This datasheet provides information on composition, physical properties, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, and joining. Filing Code: CO-109. Producer or source: Special Metals Corporation.

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